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Closed terrariums

posted by: DianaMay on 09.08.2003 at 01:03 pm in Terrariums Forum

In the past, I built many closed-system landscaped terrariums, and I thought you might find my methods informative. I had one terrarium in my home that lasted for 30 years (After I retired and moved to Texas, my son told me the dog had knocked it over. Ah well, life goes on.)

CLOSED TERRARIUM PLANTING AND CARE

Soil mixture

Do not fill the terrarium half-way up. Use as little mix as possible to give the effect you want. Styrofoam or other inert materials can be used under the mix to give height. The more mix you use, the more moisture it holds and the greater the chance of rot .

Use a mix that holds water and air, keeps plants firm, and discourages bacteria and mold. (Vermiculite holds water and air. Perlite holds air. Sand holds plants up). Use moderately coarse vermiculite alone, or a mixture of vermiculite and builder's sand or bird cage gravel. Or one third each of vermiculite, perlite and sand works well. Handle vermiculite carefully and wash hands well after use. When you water (see below), vermiculite will settle around the roots to hold a plant in place.

Keep as little of the plant�s soil as possible without breaking off too many roots. The small amount that is left will supply the plant with food for several years if the plants are kept within bounds. Do not use peat moss. It becomes waterproof when dry and requires too much water to rewet.

Do not press the mix down. Just firm material around plant enough to hold it up. Moist air needs to circulate through it.

Watering.

When starting your terrarium, water lightly around individual plants. Water will spread throughout mix by itself. Nature equalizes wet and dry. Once the humidity is properly distributed, roots will grow in the air and on the glass. Err on the side of too little rather than too much water. The terrarium should then be covered tightly with a transparent material such as Saran Wrap or glass. Wait at least one week to see if a condensation cycle starts.

If no condensation forms on the coolest side of the terrarium, during the day in very good light, add a few tablespoons of water a day until it does. Check to see that plants are getting enough light. (Inadequate light will prevent life cycles from starting.) If condensation forms on more than 1/3 of the glass, wipe it off with a paper towel and seal the top again. Do not leave it open to dry it. Plants that like high humidity will suffer. If excess condensation continues, repeat daily until only 1/3 condenses. When it is right, seal tightly, under the cover, with moistened Saran Wrap, and leave it in good light. A terrarium may go for a year or more without additional water if the proper balance of water and light have been reached, provided that it is properly sealed. You will need to open it only for housekeeping and trimming.

Mold and decay

Various molds may grow on dead material in the terrarium. Black thin little fibers with tiny spore heads may grow on dead leaves that are moist. If it does not appear to be spreading, leave it. This is often the fore-runner of moss, but may also mean the terrarium is too wet. White furry mold should be rubbed gently with a finger to disturb it as soon as it is noticed. Usually it will not persist if you rub it down a few times. Dead leaves should be left unless they are rotting against the glass. This will leave etched marks on glass that is hard to remove. If a lot of leaves are dying, give more light and wipe condensation out to make it dryer. The larger and taller the terrarium, the less likely there is to be trouble.

Insect pests

If you use materials from the wild, you may or may not want to prevent anything from hatching. (I love seeing what grows). Do not use collected wood (termites). When using wild moss (no soil), you may want to spray the back of it with a diluted liquid systemic insecticide (one that is absorbed by the plant roots). Use it sparingly and handle carefully. However, most things that hatch are easy to eliminate without chemicals.

Pests that come in on bought plants are harder to deal with, so examine all plant materials. You can use the systemic mixture on any soil around each plant if you think it is needed, but be sure to wipe out extra condensation that forms from the additional moisture. If plants are badly infected with mealybug or whitefly, it is best to snip off all leaves on the infected plant, wipe out most of the condensation in the terrarium, and wait for a healthy new crop of leaves. The result is usually satisfactory. Springtails are tiny white insects that jump around on the top of the soil when you water a plant. They are harmless and live on decaying matter so don't bother battling them.

Light

Light is the food of plants. "Plant food" is the equivalent of our minerals and vitamins. Without a good source of light, plants will gradually perish. A small terrarium cannot take sunlight because heat builds up too quickly in it. In a tall terrarium with a lot of air space this problem does not usually arise, and the sun can shine for up to three hours in the morning or late afternoon, and in winter at other times. (Moss, however, does its best in a very low, broad space like a punch bowl, with no sun.)

Do not move your plants around to follow the sun or to avoid it. Plants are oriented to the light and do not thrive if they have to repeatedly re-orient themselves. Do turn the terrarium gradually, over a period of time, if the plants are all growing to one side, or else tip the terrarium up to give the plants more even light.

Most flowering plants need sunlight to bloom, or at least to initiate bloom. Orchids and miniature sinningias and other gesneraids (members of the African violet family) can bloom easily if kept in a large enough terrarium. Keep gesneriads in small CLAY pots. They will not bloom if their roots are allowed to spread out. Use fish-tank pebbles or bird gravel to bury the little pots at an angle tipped towards the light so they will grow evenly. They need a bit of sunlight to start blooming, but usually keep it up for a long time afterwards. They will need occasional plant food and water if their pots dry out, but be sure to wipe out an equal amount of condensation.

Artificial light

Daylight in combination of fluorescent light is great. With fluorescent light alone, have the lights not more than 6 or 8 inches from top of terrarium. Incandescent light may add more of the red spectrum needed for bloom, but their red is hot. Keep the lights on up to 16 hours a day, preferably on a timer. Plants like regularity. On a fluorescent bulb, the 10 inches at either end gives inadequate light for many plants, so a set of 24" tubes alone does not have much good light. Under a 48" or 72" set of 4 bulbs, you can grow plants with high light requirements in the center, lower light at the ends. Judge adequacy by degree of etiolation (stretching). There are many new lighting systems on the market that provide much higher light and make growing under lights much more satisfying.

Diana

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clipped on: 06.26.2014 at 09:20 pm    last updated on: 06.26.2014 at 09:20 pm

RE: Blueberries - Drainage, 5-1-1 Mix and Fertilizer Q's (Follow-Up #1)

posted by: edweather on 05.03.2014 at 12:03 am in Container Gardening Forum

Sounds like you are on the right track. In my experience, I'd probably start with something like 5-2-1, or 4-2-1. I just mixed up some yesterday, and went with 4-2-1 for additional water retention. With blueberries the extra water retention is needed. As far as the drain holes, more is not better. The same amount will drain through 5 holes as 10. Just put as many as you are comfortable with. Fertilizing, you will probably get many suggestions. Personally, I'd save the organics for the ground where it will break down properly. A controlled release chemical fertilizer like Miracle Gro shake and feed for vegetables is a good addition to the mix at the start. It has the micronutrients and calcium. I'd add 1 teaspoon per gallon of mix. Blueberries don't need much fertilizing. What size/how old are the plants and how big are your containers? A lot of us fertilize with ammonium sulfate as they begin to take off. You'll probably get more suggestions. Just my .02 for now. There are many many threads on growing blueberries in containers here and over on the fruits forum. Where are you?. Adding you Zone to your profile is helpful.

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clipped on: 06.14.2014 at 09:34 pm    last updated on: 06.14.2014 at 09:35 pm

Fertilizer Program for Containerized Plants II

posted by: tapla on 03.11.2009 at 11:13 pm in Container Gardening Forum

This subject has been discussed frequently, but usually in piecemeal fashion on the Container Gardening forum and other forums related. Prompted originally by a question about fertilizers in another's post, I decided to collect a few thoughts & present a personal overview.

Fertilizer Program - Containerized Plants II

Let me begin with a brief and hopefully not too technical explanation of how plants absorb water from the soil and how they obtain the nutrients/solutes that are dissolved in that water. Most of us remember from our biology classes that cells have membranes that are semi-permeable. That is, they allow some things to pass through the walls, like water and select elements in ionic form dissolved in the water, while excluding other materials like large organic molecules. Osmosis is a natural phenomenon that is nature�s attempt at creating a balance (isotonicity) in the concentration of solutes in water inside and outside of cells. Water and ionic solutes will pass in and out of cell walls until an equilibrium is reached and the level of solutes in the water surrounding the cell is the same as the level of solutes in the cell.

This process begins when the finest roots absorb water molecule by molecule at the cellular level from the surface of soil particles and transport it, along with its nutrient load, throughout the plant. I want to keep this simple, so I�ll just say that the best water absorption occurs when the level of solutes in soil water is lowest, and in the presence of good amounts of oxygen (this is where I get to plug a well-aerated and free-draining soil), ;o). Deionized (distilled) water contains no solutes, and is easiest for plants to absorb. Of course, since distilled water contains no nutrients, using it alone practically guarantees deficiencies of multiple nutrients as the plant is shorted the building materials (nutrients) it needs to manufacture food, keep its systems orderly, and keep its metabolism running smoothly.

We already learned that if the dissolved solutes in soil water are low, the plant may be well-hydrated, but starving; however, if they are too high, the plant may have a large store of nutrients in the soil, but because of osmotic pressure, the plant may be unable to absorb the water and could die of thirst in a sea of plenty. When this condition occurs, and is severe enough (high concentrations of solutes in soil water), it causes fertilizer burn (plasmolysis), a condition seen when plasma is torn from cell walls as the water inside the cell exits to maintain solute equilibrium with the water surrounding the cell.

Our job, because you cannot depend on an adequate supply of nutrients from the organic component of a container soil, is to provide a solution of dissolved nutrients in a concentration high enough to supply nutrients in the adequate to luxury range, yet still low enough that it remains easy for the plant to take up enough water to be well-hydrated and free of drought stress. Electrical conductivity (EC) of, and the level of TDS (total dissolved solids) in the soil solution is a reliable way to judge the adequacy of solutes and the plant�s ability to take up water. There are meters that measure these concentrations, and for most plants the ideal range of conductivity is from 1.5 - 3.5 mS, with some, like tomatoes, being as high as 4.5 mS. This is more technical than I wanted to be, but I added it in case someone wanted to search "mS" or "EC". Most of us, including me, will have to be satisfied with simply guessing at concentrations, but understanding how plants take up water and fertilizer, as well as the effects of solute concentrations in soil water is an important piece of the fertilizing puzzle.

Now, some disconcerting news - you have listened to all this talk about nutrient concentrations, but what do we supply, when, and how do we supply them? We have to decide what nutrients are appropriate to add to our supplementation program, but how? Most of us are just hobby growers and cannot do tissue analysis to determine what is lacking. We can be observant and learn the symptoms of various nutrient deficiencies though - and we CAN make some surprising generalizations.

What if I said that the nutritional needs of all plants is basically the same and that one fertilizer could suit almost all the plants we grow in containers - that by increasing/decreasing the dosage as we water, we could even manipulate plants to bloom and fruit more abundantly? It�s really quite logical, so please let me explain.

Tissue analysis of plants will nearly always show NPK to be in the ratio of approximately 10:1.5:7. If we assign N the constant of 100, P and K will range from 13-19 and 45-70 respectively. (I�ll try to remember to make a chart showing the relative ratios of all the other 13 essential nutrients that don�t come from the air at the end of what I write.) All we need to do is supply nutrients in approximately the same ratio as plants use them, and in adequate amounts to keep them in the adequate to luxury range at all times.

Remember that we can maximize water uptake by keeping the concentrations of solutes low, so a continual supply of a weak solution is best. Nutrients don�t often just suddenly appear in large quantities in nature, so the low and continual dose method most closely mimics the nutritional supply Mother Nature offers. If you decide to adopt a "fertilize every time you water" approach, most liquid fertilizers can be applied at � to 1 tsp per gallon for best results. If you decide that�s too much work, try halving the dose recommended & cutting the interval in half. You can work out the math for granular soluble fertilizers and apply at a similar rate.

The system is rather self regulating if fertilizer is applied in low concentrations each time you water, even with houseplants in winter. As the plant�s growth slows, so does its need for both water and nutrients. Larger plants and plants that are growing robustly will need more water and nutrients, so linking nutrient supply to the water supply is a win/win situation all around.

Another advantage to supplying a continual low concentration of fertilizer is it eliminates the tendency of plants to show symptoms of nutrient deficiencies after they have received high doses of fertilizer and then been allowed to return to a more favorable level of soil solute concentrations. Even at perfectly acceptable concentrations of nutrients in the soil, plants previously exposed to high concentrations of fertilizer readily display these symptoms.

You will still need to guard against watering in sips, and that habit�s accompanying tendency to allow solute (salt) accumulation in soils. Remember that as salts accumulate, both water and nutrient uptake is made more difficult and finally impaired or made impossible in severe cases. Your soils should always allow you to water so that at least 10-15% of the total volume of water applied passes through the soil and out the drain hole to be discarded. This flushes the soil and carries accumulating solutes out the drain hole.

I have recently switched to a liquid fertilizer with micronutrients in a 12:4:8 NPK ratio. Note how closely this fit�s the average ratio of NPK content in plant tissues, noted above (10:1.5:7). If the P looks a little high at 4, consider that in container soils, P begins to be more tightly held as pH goes from 6.5 to below 6.0, which is on the high side of most container soil�s pH, so the manufacturer probably gave this some careful consideration. Also, P and K percentages shown on fertilizer packages are not the actual amount of P or K in the blend. The percentage of P on the package is the percentage of P2O5 (phosphorous pentoxide) and you need to multiply the percentage shown by .43 to get the actual amount of P in the fertilizer. Similarly, the K level percentage shown is actually the level of K2O ( potassium oxide) and must be multiplied by .83 to arrive at the actual amount of K supplied.

To answer the inevitable questions about specialty fertilizers and "special" plant nutritional requirements, let me repeat that plants need nutrients in roughly the same ratio. Ratio is an entirely a separate consideration from dosage. You�ll need to adjust the dosage to fit the plant and perhaps strike a happy medium in containers that have a diversity of material.

If nutrient availability is unbalanced - if plants are getting more than they need of certain nutrients, but less than they need of others, the nutrient they need the most will be the one that limits growth. There are 6 factors that affect plant growth and yield; they are: air water light temperature soil or media nutrients. Liebig's Law of Limiting Factors states the most deficient factor limits plant growth and increasing the supply of non-limiting factors will not increase plant growth. Only by increasing most deficient nutrient will the plant growth increase. There is also an optimum combination?ratio of the nutrients and increasing them, individually or in various combinations, can lead to toxicities.

When individual nutrients are available in excess, it not only unnecessarily contributes to the total volume of solutes in the soil solution, which makes it more difficult for the plant to absorb water and nutrients, it also often creates an antagonistic deficiency of other nutrients as toxicity levels block a plant's ability to take up other nutrients. E.g., too much Fe (iron) can cause a Mn (manganese) deficiency, with the converse also true, Too much Ca (calcium) can cause a Mg (magnesium) deficiency. Too much P (phosphorous) can cause an insoluble precipitate with Fe and make Fe unavailable. It also interferes with the uptake of several other micro-nutrients. You can see why it�s advantageous to supply nutrients in as close to the same ratio in which plants use them and at levels not so high that they interfere with water uptake. I know I�m repeating myself here, but this is an important point.

What about the high-P "Bloom Booster" fertilizers you might ask? To induce more prolific flowering, a reduced N supply will have more and better effect than the high P bloom formulas. When N is reduced, it slows vegetative growth without reducing photosynthesis. Since vegetative growth is limited by a lack of N, and the photosynthetic machinery continues to turn out food, it leaves an expendable surplus for the plant to spend on flowers and fruit. Plants use about 6 times more N than P, so fertilizers that supply more P than N are wasteful and more likely to inhibit blooms (remember that too much P inhibits uptake of Fe and many micro-nutrients - it raises pH unnecessarily as well, which could also be problematic). Popular "bloom-booster" fertilizers like 10-52-10 actually supply about 32x more P than your plant could ever use (in relationship to how much N it uses) and has the potential to wreak all kinds of havoc with your plants.

The fact that different species of plants grow in different types of soil where they are naturally found, does not mean that one needs more of a certain nutrient than the other. It just means that the plants have developed strategies to adapt to certain conditions, like excesses and deficiencies of particular nutrients.

Plants that "love" acid soils, e.g., have simply developed strategies to cope with those soils. Their calcium needs are still the same as any other plant and no different from the nutrient requirements of plants that thrive in alkaline soils. The problem for acid-loving plants is that they are unable to adequately limit their calcium uptake, and will absorb too much of it when available, resulting in cellular pH-values that are too high. Some acid-loving plants also have difficulties absorbing Fe, Mn, Cu, or Zn, which is more tightly held in alkaline soils, another reason why they thrive in low pH (acid) soils.

So, If you select a fertilizer that is close in ratio to the concentration of major elements in plant tissues, you�re going to be in good shape. Whether the fertilizer is furnished in chemical or organic form matters not a whit to the plant. Ions are ions, but there is one major consideration. Chemical fertilizers are available for immediate uptake while organic fertilizers must be acted on by passing through the gut of micro-organisms to break them down into usable elemental form. Since microorganism populations are affected by cultural conditions like moisture/air levels in the soil, soil pH, fertility levels, temperature, etc., they tend to follow a boom/bust cycle in container culture, which has an impact on the reliability and timing of delivery of nutrients supplied in organic form. Nutrients locked in hydrocarbon chains cannot be relied upon to be available when the plant needs them. This is particularly an issue with the immobile nutrients that must be present in the nutrient stream at all times for the plant to grow normally.

What is my approach? I have been very happy with Miracle-Gro 12-4-8 all purpose liquid fertilizer, or 24-8-16 Miracle-Gro granular all-purpose fertilizer - both are completely soluble. I incorporate a granular micro-nutrient supplement in my soils when I make them (Micromax) or use a soluble micro-nutrient blend (STEM). I would encourage you to make sure your plants are getting all the micro-nutrients. More readily available than the supplements I use is Earth Juice�s �Microblast�. Last year, I discovered a fertilizer by Dyna-Gro called Foliage-Pro 9-3-6. It is a 3:1:2 ratio like I like and has ALL the primary macro-nutrients, secondary macro-nutrients (Ca, Mg, S) and all the micro-nutrients. It performed very well for me.

When plants are growing robustly, I try to fertilize my plants weakly (pun intended) with a half recommended dose of the concentrate at half the suggested intervals. When plants are growing slowly, I fertilize more often with very weak doses. It�s important to realize your soil must drain freely and you must water so a fair amount of water drains from your container each time you water to fertilize this way. This year my display containers performed better than they ever have in years past & they were still all looking amazingly attractive at the beginning of Oct when I finally decided to dismantle them because of imminent cold weather. I attribute results primarily to a good soil and a healthy nutrient supplementation program.

What would I recommend to someone who asked what to use as an all-purpose fertilizer for nearly all their container plantings? If you can find it, a 3:1:2 ratio soluble liquid fertilizer (24-8-16, 12-4-8, 9-3-6 are all 3:1:2 ratio fertilizers) that contains all the minor elements would great.

How plants use nutrients - the chart I promised:

I gave Nitrogen, because it's the largest nutrient component, the value of 100. Other nutrients are listed as a weight percentage of N.
N 100
P 13-19 (16) 1/6
K 45-80 (62) 3/5
S 6-9 (8) 1/12
Mg 5-15 (10) 1/10
Ca 5-15 (10) 1/10
Fe 0.7
Mn 0.4
B(oron) 0.2
Zn 0.06
Cu 0.03
Cl 0.03
M(olybden) 0.003
To read the chart: P - plants use 13-19 parts of P or an average of about 16 parts for every 100 parts of N, or 6 times more N than P. Plants use about 45-80 parts of K or an average of about 62 parts for every 100 parts of N, or about 3/5 as much K as N, and so on.

If you're still awake - thanks for reading. It makes me feel like the effort was worth it. ;o) Let me know what you think - please.
Al

Here is a link to the first posting of A Fertilizer Program for Containers

Another link to information about Container Soils- Water Movement and Retention

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clipped on: 06.12.2014 at 09:26 pm    last updated on: 06.12.2014 at 09:26 pm

RE: Gritty Mix + Citrus Plants + Foilage Pro - Questions (Follow-Up #20)

posted by: tapla on 02.20.2011 at 12:20 pm in Container Gardening Forum

Redshirt - you must have misunderstood about the Ca:Mg ratio of FP 9-3-6. It is perfect insofar as the Ca:Mg ratio goes, AND it is also perfect relative to the % of N supplied. The most important considerations for fertilizer from the plant's perspective is what is available and when, and how much of each nutrient is present in relation to other nutrients. I can see there was a lot of thought that went into developing the fertilizer because the 3:1:2 ratio is about as close as you can get to what plants actually use (a decided advantage when it comes to our trying to keep EC/TDS levels low and still not have our plants suffering deficiencies), and because all 12 nutrients plants take from the soil are present in a favorable ratio to each other.

The rule of thumb: Use dolomitic (garden) lime in the 5:1:1 soil except under unique & specific circumstances that are prolly not worth mentioning now. For the gritty mix, use gypsum as a Ca source IF your fertilizer does not contain Ca. Most soluble fertilizers do not, because they use urea as their N source. Ca nitrate is the only suitable soluble source of Ca and it is much more expensive than urea. Plus, most container soils are pH adjusted with dolomitic lime, which acts as a Ca source. The gritty mix would be too high in pH to be optimal if we added lime, so we limit the Ca source to something that is pH neutral - gypsum. Foliage pro does have Ca, and all the plants I've grown so far show no signs of Ca deficiencies if I use 9-3-6 and leave the gypsum out, but you DO need it if you're using MG, Schultz, Peter's ...

IF you use gypsum and your fertilizer does NOT have Mg, you need to supplement the Mg by adding Epsom salts each time you fertilize. Do this by including 1/8 - 1/4 tsp of Epsom salts per gallon of water each time you fertilize.

FP sometimes shows a tendency for the Ca to precipitate out of solution at times - especially when it gets cold. Warming the fertilizer before using it, and diluting it 1:1 with water before using it in your injector system will ensure the Ca stays in solution. It will also ensure the added MgSO4 (Epsom salts) you add to your fertilizer solution will dissolve properly and not cause additional Ca to precipitate out of solution.

I really need to get an injector system to both acidify my irrigation water (mine comes in at a pH of about 8.5-8.8) and to speed the fertilizing process. I actually fertilize 300+ containers in the summer by hand (2-1/2 gallon watering can) on pretty much a weekly basis. It's a drag ..... but a good thing I love being outdoors. I could probably spend the 3+ hours it takes to fertilize every weekend doing something not so tedious. Note: I could easily take the easier road & fertilize at a higher, instead of at a reduced rate, & extend the interval to 2 weeks instead of weekly, but the plants keep telling me they like the more frequent low doses (especially when it's rather hot or quite cool), so .....

Al

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clipped on: 06.11.2014 at 09:15 am    last updated on: 06.11.2014 at 09:15 am

RE: Gritty Mix + Citrus Plants + Foilage Pro - Questions (Follow-Up #3)

posted by: tapla on 02.16.2011 at 11:24 am in Container Gardening Forum

MgSO4 and CaSO4 are essentially pH neutral, so please don't think about using either to either raise or lower pH. It will be fruitless.

Get a test kit and determine how much white vinegar or citric acid (where they sell wine making supplies) it takes to lower your tap water to a pH of 5.0-5.5. Make a note & water with the treated water each time you water or fertigate.

* Don't let the roots dry out - ever. Keep them wet all the while you're working on them. I put some soil inn the pot, then situate the plant, PARTIALLLY covering the roots a little at a time - working the soil into the roots. If I think there is any danger of the roots drying out, I'll spritz. You'll only need to do this at first because your progress will be slower that it will after you get proficient.

IF your fertilizer doesn't contain Ca, add 1 tbsp of gypsum per gallon of soil. If it does contain Ca (like FP), no gypsum required. The same with Mg/Epsom salts. Ask if this isn't clear.

Plants form partnerships with lots of soil life. I often find certain types of fungi growing in the gritty mix when conditions are favorable, but I rely on the fact that all the essential nutrients will be in the soil solution and readily available for uptake at all times. Try to think of growing in the gritty mix as one step closer to hydroponics than growing in sludgy soils, which are already well-removed from growing in the ground. If you can grow perfectly healthy plants hydroponically w/o fungal symbiosis, you can do the same in container culture with a good nutrition supplementation program (right pH and fertilizer).

Fertilizer ions anions are held on colloidal surfaces at attachment sites. (look up CEC or Cation Exchange Capacity) A LOT of people think that because you water more often & the water runs through the soil that you are flushing the soil of all fertilizer, but it doesn't work that way to the degree most think it does. You can fertilize however you like. Weak doses each time you water - weakly weekly - every 2-3 weeks. I fertilize every time I water in the winter (houseplants/bonsai) - even the plants in weak light. Water use is determined largely by growth & transpiration rates, so fertilizer rates that are tied to the water supply are pretty much self-regulating - another fact that many fail to grasp. This only works with soils that allow you to flush the soil when you water. Sludgy soils that are watered in sips virtually assure a steady increase in the level of solubles in the soil solution,. unless you make the concerted effort to remove them regularly by flushing; but then you have the excess water retention to deal with .....

Turface is baked clay - dirt. It id fired to the melting point so it expands & fuses. It's inert, so there is nothing in Turface you wouldn't find in clay soils.

After reading what everyone offered - if you still have questions, don't hesitate .....

Good luck!!!

Al


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clipped on: 06.11.2014 at 09:01 am    last updated on: 06.11.2014 at 09:01 am

RE: succulent soil mix (Follow-Up #2)

posted by: tapla on 11.02.2007 at 04:10 pm in Container Gardening Forum

Below, you'll find a few thumbnails to click on if you're interested. Sorry that I didn't take much time to take especially pretty photos. ;o) Just wanted you to see what I grow houseplants and succulents in. If you look past the hail damage, you can see the plants are very pleased with what their feet are in.













I always have a mix of equal parts of Turface, crushed granite (grower/turkey grit), and fir bark on hand because it's my basic bonsai soil mix. I add some very coarse sand, and vermiculite, along with a little gypsum & dolomitic lime to it to round things out. Here's the formula:
3 parts Turface
3 parts crushed granite (farm feed store)
3 parts pine or fir bark (see photo for size)
1 part coarse silica sand (masonry supply company)
1 part vermiculite
CRF (18-4-9 is what I use, but anything with a high first # or close to a 3-1-2 ratio works well)
Dolomitic lime & gypsum
Micronutrient granules

********************************************************************** ************************

The Turface or a similar product is important.

Notice the lack of a large variance in particle size.

You could eliminate either the granite or sand by varying ratios or with a similar product.

The CRF is not necessary if you're diligent about your nutrient supplementation program.

I can help you determine how much dolomite & gypsum to add when I know your batch size.

You don't need peat in your mix, and the mix you're looking at is approx 75% mineral/inorganic. I grow some plants with a 0% organic component, so don't let that bother you. This soil is extremely consistent in how it performs over time and very structurally stable.

Al

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clipped on: 06.11.2014 at 08:48 am    last updated on: 06.11.2014 at 08:48 am

RE: Pine Bark Fines Substitute? (Follow-Up #31)

posted by: tapla on 04.15.2011 at 01:53 pm in Container Gardening Forum

Rises4 - I think I would skip the Scott's Premium Topsoil, just because topsoil and/or a high % of pine particulates are not such a good choices for inclusion in container media. From The Scott's web page about this product, under the tab Details and Usage:

Where to Use
For use in lawn and gardens.

Where Not to Use
Not for container planting.

Margo - we start with the large bark particles to ensure we get great aeration, then we add enough fine particles (peat) to make sure we get enough water retention w/o destroying aeration. You want somewhere around 80% of the particles to be larger than 1/8", and the rest to be fine, so use that as a guide. If your bark has a LOT of fines and is generally small in size, you prolly don't need any peat; but if it's large, with few fines, you might need a little more peat. You basically want as much aeration as you can get w/o creating watering problems for yourself. One of the great things about making your own soils is you can adjust the water retention to whatever you feel you need/want.

Al

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clipped on: 06.11.2014 at 08:45 am    last updated on: 06.11.2014 at 08:45 am

RE: Pine Bark Fines Substitute? (Follow-Up #6)

posted by: tapla on 11.22.2010 at 08:35 am in Container Gardening Forum

Fines are ...... well, ..... fines. The best sizes for the 5:1:1 mix are dust to 3/8". The gritty mix works best with bark sized 1/8 - 1/4".

Al

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clipped on: 06.11.2014 at 08:36 am    last updated on: 06.11.2014 at 08:36 am

RE: 100% Synthetic Potting Mix? (Follow-Up #7)

posted by: Jay-Part-Shade on 06.03.2014 at 11:34 pm in Container Gardening Forum

Hey Nil,

Great info! Exactly what I'm looking for, and good points about inorganic.

Other than cost and convenience, is there a reason more people don't replace the bark/peat with pumice/lava/turface? The big issue with the 5-1-1 I've found is there's a bell curve of when the mix is best suited for the plants after it's brewed for a few months and before it decomposes into mush. I think I've seen some of your plants before - what do you use?

Below is a chart from Growstones about water/air retention. I'd be great to include pumice/lava/turface/etc. so we know where they stand. I'm having a hard time finding this info. If anyone has it, I'll make another chart.

And funny enough, if you're in Mt. Washington, I'm probably 5 mins from you in Atwater.

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clipped on: 06.10.2014 at 10:15 pm    last updated on: 06.10.2014 at 10:15 pm

RE: Lava rock in gritty mix (Follow-Up #4)

posted by: Joe1980 on 06.03.2014 at 12:00 pm in Container Gardening Forum

So basically, lava rock is right between grit and turface. That would lead me to believe that if used to replace any fraction of grit, it will add moisture, and if used to replace any fraction of turface, it would reduce moisture. So, if I were to use 1:1:1 of all three, it would pretty much hold the same moisture as my current 1:1 turface/grit combo.

Good news is, even up here in Wisconsin, I've found a source of red lava pebbles either in bulk or in 60# bags. The size they claim is 3/8" and under, which seems good to me. I will obviously sift out the fines like I do turface, but what size should I sift on the upper end?

Joe

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clipped on: 06.10.2014 at 10:10 pm    last updated on: 06.10.2014 at 10:10 pm

Container Soils - Water Movement and Retention XIX

posted by: tapla on 04.29.2014 at 06:37 pm in Container Gardening Forum

I guess I wasn't paying close enough attention to the last thread. I like to leave a link at the end of the previous to the new thread, which would be this one.

Container Soils - Water Movement and Retention XIX
I first posted this thread back in March of '05. So far, it has reached the maximum number of posts GW allows to a single thread eighteen times, which is much more attention than I ever imagined it would garner. I have reposted it in no small part because it has been great fun, and a wonderful catalyst in the forging of new friendships and in increasing my list of acquaintances with similar growing interests. The forum and email exchanges that stem so often from the subject are in themselves enough to make me hope the subject continues to pique interest, and the exchanges provide helpful information. Most of the motivation for posting this thread another time comes from the reinforcement of hundreds of participants over the years that strongly suggests the information provided in good-spirited collective exchange has made a significant difference in the quality of their growing experience. I'll provide links to some of the more recent of the previous dozen threads and nearly 2,500 posts at the end of what I have written - just in case you have interest in reviewing them. Thank you for taking the time to examine this topic - I hope that any/all who read it take at least something interesting and helpful from it. I know it's long. My hope is that you find it worth the read, and the time you invest results in a significantly improved growing experience.
Since there are many questions about soils appropriate for use in containers, I'll post basic mix recipes later, in case any would like to try the soil. It will follow the information.

Before we get started, I'd like to mention that I wrote a reply and posted it to a thread recently, and I think it is well worth considering. It not only sets a minimum standard for what constitutes a 'GOOD' soil, but also points to the fact that not all growers look at container soils from the same perspective, which is why growers so often disagree on what makes a 'good' soil. I hope you find it thought provoking:

Is Soil X a 'Good' Soil?

I think any discussion on this topic must largely center around the word "GOOD", and we can broaden the term 'good' so it also includes 'quality' or 'suitable', as in "Is soil X a quality or suitable soil?"

How do we determine if soil A or soil B is a good soil? and before we do that, we'd better decide if we are going to look at it from the plant's perspective or from the grower's perspective, because often there is a considerable amount of conflict to be found in the overlap - so much so that one can often be mutually exclusive of the other.

We can imagine that grower A might not be happy or satisfied unless knows he is squeezing every bit of potential from his plants, and grower Z might not be happy or content unless he can water his plants before leaving on a 2-week jaunt, and still have a weeks worth of not having to water when he returns. Everyone else is somewhere between A and Z; with B, D, F, H, J, L, N, P, R, T, V, X, and Y either unaware of how much difference soil choice can make, or they understand but don't care.

I said all that to illustrate the large measure of futility in trying to establish any sort of standard as to what makes a good soil from the individual grower's perspective; but let's change our focus from the pointless to the possible.

We're only interested in the comparative degrees of 'good' and 'better' here. It would be presumptive to label any soil "best". 'Best I've found' or 'best I've used' CAN sometimes be useful for comparative purposes, but that's a very subjective judgment. Let's tackle 'good', then move on to 'better', and finally see what we can do about qualifying these descriptors so they can apply to all growers.

I would like to think that everyone would prefer to use a soil that can be described as 'good' from the plant's perspective. How do we determine what a plant wants? Surprisingly, we can use %s established by truly scientific studies that are widely accepted in the greenhouse and nursery trades to determine if a soil is good or not good - from the plant's perspective, that is. Rather than use confusing numbers that mean nothing to the hobby grower, I can suggest that our standard for a good soil should be, at a minimum, that you can water that soil properly. That means, that at any time during the growth cycle, you can water your plantings to beyond the point of saturation (so excess water is draining from the pot) without the fear of root rot or compromised root function or metabolism due to (take your pick) too much water or too little air in the root zone.

I think it's very reasonable to withhold the comparative basic descriptor, 'GOOD', from soils that can't be watered properly without compromising root function, or worse, suffering one of the fungaluglies that cause root rot. I also think anyone wishing to make the case from the plant's perspective that a soil that can't be watered to beyond saturation w/o compromising root health can be called 'good', is fighting on the UP side logic hill.

So I contend that 'good' soils are soils we can water correctly; that is, we can flush the soil when we water without concern for compromising root health/function/metabolism. If you ask yourself, "Can I water correctly if I use this soil?" and the answer is 'NO' ... it's not a good soil ... for the reasons stated above.

Can you water correctly using most of the bagged soils readily available? 'NO', I don't think I need to point to a conclusion.

What about 'BETTER'? Can we determine what might make a better soil? Yes, we can. If we start with a soil that meets the minimum standard of 'good', and improve either the physical and/or chemical properties of that soil, or make it last longer, then we have 'better'. Even if we cannot agree on how low we wish to set the bar for what constitutes 'good', we should be able to agree that any soil that reduces excess water retention, increases aeration, ensures increased potential for optimal root health, and lasts longer than soils that only meet some one's individual and arbitrary standard of 'good', is a 'better' soil.

All the plants we grow, unless grown from seed, have the genetic potential to be beautiful specimens. It's easy to say, and easy to see the absolute truth in the idea that if you give a plant everything it wants it will flourish and grow; after all, plants are programmed to grow just that way. Our growing skills are defined by our ability to give plants what they want. The better we are at it, the better our plants will grow. But we all know it's not that easy. Lifetimes are spent in careful study, trying to determine just exactly what it is that plants want and need to make them grow best.

Since this is a soil discussion, let's see what the plant wants from its soil. The plant wants a soil in which we have endeavored to provide in available form, all the essential nutrients, in the ratio in at which the plant uses them, and at a concentration high enough to prevent deficiencies yet low enough to make it easy to take up water (and the nutrients dissolved in the water). First and foremost, though, the plant wants a container soil that is evenly damp, never wet or soggy. Giving a plant what it wants, to flourish and grow, doesn't include a soil that is half saturated for a week before aeration returns to the entire soil mass, even if you only water in small sips. Plants might do 'ok' in some soils, but to actually flourish, like they are genetically programmed to do, they would need to be unencumbered by wet, soggy soils.

We become better growers by improving our ability to reduce the effects of limiting factors, or by eliminating those limiting factors entirely; in other words, by clearing out those influences that stand in the way of the plant reaching its genetic potential. Even if we are able to make every other factor that influences plant growth/vitality absolutely perfect, it could not make up for a substandard soil. For a plant to grow to its genetic potential, every factor has to be perfect, including the soil. Of course, we'll never manage to get to that point, but the good news is that as we get closer and closer, our plants get better and better; and hopefully, we'll get more from our growing experience.

In my travels, I've discovered it almost always ends up being that one little factor that we willingly or unwittingly overlooked that limits us in our abilities, and our plants in their potential.

Food for thought:
A 2-bit plant in a $10 soil has a future full of potential, where a $10 plant in a 2-bit soil has only a future filled with limitations. ~ Al

Container Soils - Water Movement & Retention

As container gardeners, our first priority should be to ensure the soils we use are adequately aerated for the life of the planting, or in the case of perennial material (trees, shrubs, garden perennials), from repot to repot. Soil aeration/drainage is the most important consideration in any container planting. Soils are the foundation that all container plantings are built on, and aeration is the very cornerstone of that foundation. Since aeration and drainage are inversely linked to soil particle size, it makes good sense to try to find and use soils or primary components with particles larger than peat/compost/coir. Durability and stability of soil components so they contribute to the retention of soil structure for extended periods is also extremely important. Pine and some other types of conifer bark fit the bill nicely, but I'll talk more about various components later.

What I will write also hits pretty hard against the futility in using a drainage layer of coarse materials in attempt to improve drainage. It just doesn't work. All it does is reduce the total volume of soil available for root colonization. A wick can be employed to remove water from the saturated layer of soil at the container bottom, but a drainage layer is not effective. A wick can be made to work in reverse of the self-watering pots widely being discussed on this forum now.

Consider this if you will:

Container soils are all about structure, and particle size plays the primary role in determining whether a soil is suited or unsuited to the application. Soil fills only a few needs in container culture. Among them are: Anchorage - a place for roots to extend, securing the plant and preventing it from toppling. Nutrient Retention - it must retain a nutrient supply in available form sufficient to sustain plant systems. Gas Exchange - it must be amply porous to allow air to move through the root system and gasses that are the by-product of decomposition to escape. Water - it must retain water enough in liquid and/or vapor form to sustain plants between waterings. Air - it must contain a volume of air sufficient to ensure that root function/metabolism/growth is not impaired. This is extremely important and the primary reason that heavy, water-retentive soils are so limiting in their affect. Most plants can be grown without soil as long as we can provide air, nutrients, and water, (witness hydroponics). Here, I will concentrate primarily on the movement and retention of water in container soil(s).

There are two forces that cause water to move through soil - one is gravity, the other capillary action. Gravity needs little explanation, but for this writing I would like to note: Gravitational flow potential (GFP) is greater for water at the top of the container than it is for water at the bottom. I'll return to that later.

Capillarity is a function of the natural forces of adhesion and cohesion. Adhesion is water's tendency to stick to solid objects like soil particles and the sides of the pot. Cohesion is the tendency for water to stick to itself. Cohesion is why we often find water in droplet form - because cohesion is at times stronger than adhesion; in other words, water's bond to itself can be stronger than the bond to the object it might be in contact with; cohesion is what makes water form drops. Capillary action is in evidence when we dip a paper towel in water. The water will soak into the towel and rise several inches above the surface of the water. It will not drain back into the source, and it will stop rising when the GFP equals the capillary attraction of the fibers in the paper.

There will be a naturally occurring "perched water table" (PWT) in containers when soil particulate size is under about .100 (just under 1/8) inch. Perched water is water that occupies a layer of soil at the bottom of containers or above coarse drainage layers that tends to remain saturated & will not drain from the portion of the pot it occupies. It can evaporate or be used by the plant, but physical forces will not allow it to drain. It is there because the capillary pull of the soil at some point will surpass the GFP; therefore, the water does not drain, it is said to be 'perched'. The smaller the size of the particles in a soil, the greater the height of the PWT. Perched water can be tightly held in heavy (comprised of small particles) soils where it perches (think of a bird on a perch) just above the container bottom where it will not drain; or, it can perch in a layer of heavy soil on top of a coarse drainage layer, where it will not drain.

Imagine that we have five cylinders of varying heights, shapes, and diameters, each with drain holes. If we fill them all with the same soil mix, then saturate the soil, the PWT will be exactly the same height in each container. This saturated area of the container is where roots initially seldom penetrate & where root problems frequently begin due to a lack of aeration and the production of noxious gasses. Water and nutrient uptake are also compromised by lack of air in the root zone. Keeping in mind the fact that the PWT height is dependent on soil particle size and has nothing to do with height or shape of the container, we can draw the conclusion that: If using a soil that supports perched water, tall growing containers will always have a higher percentage of unsaturated soil than squat containers when using the same soil mix. The reason: The level of the PWT will be the same in each container, with the taller container providing more usable, air holding soil above the PWT. From this, we could make a good case that taller containers are easier to grow in.

A given volume of large soil particles has less overall surface area when compared to the same volume of small particles and therefore less overall adhesive attraction to water. So, in soils with large particles, GFP more readily overcomes capillary attraction. They simply drain better and hold more air. We all know this, but the reason, often unclear, is that the height of the PWT is lower in coarse soils than in fine soils. The key to good drainage is size and uniformity of soil particles. Mixing large particles with small is often very ineffective because the smaller particles fit between the large, increasing surface area which increases the capillary attraction and thus the water holding potential. An illustrative question: How much perlite do we need to add to pudding to make it drain well?

I already stated I hold as true that the grower's soil choice when establishing a planting for the long term is the most important decision he/she will make. There is no question that the roots are the heart of the plant, and plant vitality is inextricably linked in a hard lock-up with root vitality. In order to get the best from your plants, you absolutely must have happy roots.

If you start with a water-retentive medium, you cannot effectively amend it to improve aeration or drainage characteristics by adding larger particulates. Sand, perlite, Turface, calcined DE ...... none of them will work effectively. To visualize why sand and perlite can't change drainage/aeration, think of how well a pot full of BBs would drain (perlite); then think of how poorly a pot full of pudding would drain (bagged soil). Even mixing the pudding and perlite/BBs together 1:1 in a third pot yields a mix that retains the drainage characteristics and PWT height of the pudding. It's only after the perlite become the largest fraction of the mix (60-75%) that drainage & PWT height begins to improve. At that point, you're growing in perlite amended with a little potting soil.

You cannot add coarse material to fine material and improve drainage or the ht of the PWT. Use the same example as above & replace the pudding with play sand or peat moss or a peat-based potting soil - same results. The benefit in adding perlite to heavy soils doesn't come from the fact that they drain better. The fine peat or pudding particles simply 'fill in' around the perlite, so drainage & the ht of the PWT remains the same. All perlite does in heavy soils is occupy space that would otherwise be full of water. Perlite simply reduces the amount of water a soil is capable of holding because it is not internally porous. IOW - all it does is take up space. That can be a considerable benefit, but it makes more sense to approach the problem from an angle that also allows us to increase the aeration AND durability of the soil. That is where Pine bark comes in, and I will get to that soon.

If you want to profit from a soil that offers superior drainage and aeration, you need to start with an ingredient as the basis for your soils that already HAVE those properties, by ensuring that the soil is primarily comprised of particles much larger than those in peat/compost/coir/sand/topsoil, which is why the recipes I suggest as starting points all direct readers to START with the foremost fraction of the soil being large particles, to ensure excellent aeration. From there, if you choose, you can add an appropriate volume of finer particles to increase water retention. You do not have that option with a soil that is already extremely water-retentive right out of the bag.

I fully understand that many are happy with the results they get when using commercially prepared soils, and I'm not trying to get anyone to change anything. My intent is to make sure that those who are having trouble with issues related to soil, understand why the issues occur, that there are options, and what they are.

We have seen that adding a coarse drainage layer at the container bottom does not improve drainage. It does though, reduce the volume of soil required to fill a container, making the container lighter. When we employ a drainage layer in an attempt to improve drainage, what we are actually doing is moving the level of the PWT higher in the pot. This simply reduces the volume of soil available for roots to colonize. Containers with uniform soil particle size from top of container to bottom will yield better and more uniform drainage and have a lower PWT than containers using the same soil with added drainage layers.

The coarser the drainage layer, the more detrimental to drainage it is because water is more (for lack of a better scientific word) reluctant to make the downward transition because the capillary pull of the soil above the drainage layer is stronger than the GFP. The reason for this is there is far more surface area on soil particles for water to be attracted to in the soil above the drainage layer than there is in the drainage layer, so the water perches. I know this goes against what most have thought to be true, but the principle is scientifically sound, and experiments have shown it as so. Many nurserymen employ the pot-in-pot or the pot-in-trench method of growing to capitalize on the science.

If you discover you need to increase drainage, you can simply insert an absorbent wick into a drainage hole & allow it to extend from the saturated soil in the container to a few inches below the bottom of the pot, or allow it to contact soil below the container where the earth acts as a giant wick and will absorb all or most of the perched water in the container, in most cases. Eliminating the PWT has much the same effect as providing your plants much more soil to grow in, as well as allowing more, much needed air in the root zone.

In simple terms: Plants that expire because of drainage problems either die of thirst because the roots have rotted and can no longer take up water, or they suffer/die because there is insufficient air at the root zone to insure normal root function, so water/nutrient uptake and root metabolism become seriously impaired.

To confirm the existence of the PWT and how effective a wick is at removing it, try this experiment: Fill a soft drink cup nearly full of garden soil. Add enough water to fill to the top, being sure all soil is saturated. Punch a drain hole in the bottom of the cup and allow the water to drain. When drainage has stopped, insert a wick into the drain hole . Take note of how much additional water drains. Even touching the soil with a toothpick through the drain hole will cause substantial additional water to drain. The water that drains is water that occupied the PWT. A greatly simplified explanation of what occurs is: The wick or toothpick "fools" the water into thinking the pot is deeper than it is, so water begins to move downward seeking the "new" bottom of the pot, pulling the rest of the water in the PWT along with it. If there is interest, there are other simple and interesting experiments you can perform to confirm the existence of a PWT in container soils. I can expand later in the thread.

I always remain cognizant of these physical principles whenever I build a soil. I have not used a commercially prepared soil in many years, preferring to build a soil or amend one of my 2 basic mixes to suit individual plantings. I keep many ingredients at the ready for building soils, but the basic building process usually starts with conifer bark and perlite. Sphagnum peat plays a secondary role in my container soils because it breaks down too quickly to suit me, and when it does, it impedes drainage and reduces aeration. Size matters. Partially composted conifer bark fines (pine is easiest to find and least expensive) works best in the following recipes, followed by uncomposted bark in the <3/8" range.

Bark fines of pine, fir or hemlock, are excellent as the primary component of your soils. The lignin contained in bark keeps it rigid and the rigidity provides air-holding pockets in the root zone far longer than peat or compost mixes that too quickly break down to a soup-like consistency. Conifer bark also contains suberin, a lipid sometimes referred to as nature's preservative. Suberin, more scarce as a presence in sapwood products and hardwood bark, dramatically slows the decomposition of conifer bark-based soils. It contains highly varied hydrocarbon chains and the microorganisms that turn peat to soup have great difficulty cleaving these chains - it retains its structure.

Note that there is no sand or compost in the soils I use. Sand, as most of you think of it, can improve drainage in some cases, but it reduces aeration by filling valuable macro-pores in soils. Unless sand particle size is fairly uniform and/or larger than about BB size, I leave it out of soils. Compost is too fine and unstable for me to consider using in soils in any significant volume as well. The small amount of micro-nutrients it supplies can easily be delivered by one or more of a number of chemical or organic sources that do not detract from drainage/aeration.

The basic soils I use ....

The 5:1:1 mix:

5 parts pine bark fines, dust - 3/8 (size is important
1 part sphagnum peat (not reed or sedge peat please)
1-2 parts perlite (coarse, if you can get it)
garden lime (or gypsum in some cases)
controlled release fertilizer (if preferred)

Big batch:
2-3 cu ft pine bark fines
5 gallons peat
5 gallons perlite
2 cups dolomitic (garden) lime (or gypsum in some cases)
2 cups CRF (if preferred)

Small batch:
3 gallons pine bark
1/2 gallon peat
1/2 gallon perlite
4 tbsp lime (or gypsum in some cases)
1/4 cup CRF (if preferred)

I have seen advice that some highly organic (practically speaking - almost all container soils are highly organic) container soils are productive for up to 5 years or more. I disagree and will explain why if there is interest. Even if you were to substitute fir bark for pine bark in this recipe (and this recipe will long outlast any peat based soil) you should only expect a maximum of two to three years life before a repot is in order. Usually perennials, including trees (they're perennials too) should be repotted more frequently to insure they can grow at as close to their genetic potential within the limits of other cultural factors as possible. If a soil is desired that will retain structure for long periods, we need to look more to inorganic components. Some examples are crushed granite, fine stone, VERY coarse sand (see above - usually no smaller than BB size in containers, please), Haydite, lava rock (pumice), Turface, calcined DE, and others.

For long term (especially woody) plantings and houseplants, I use a superb soil that is extremely durable and structurally sound. The basic mix is equal parts of screened pine bark, Turface, and crushed granite.

The gritty mix:

1 part uncomposted screened pine or fir bark (1/8-1/4")
1 part screened Turface
1 part crushed Gran-I-Grit (grower size) or #2 cherrystone
1 Tbsp gypsum per gallon of soil (eliminate if your fertilizer has Ca)
CRF (if desired)

I use 1/8 -1/4 tsp Epsom salts (MgSO4) per gallon of fertilizer solution when I fertilize if the fertilizer does not contain Mg (check your fertilizer - if it is soluble, it is probable it does not contain Ca or Mg. If I am using my currently favored fertilizer (I use it on everything), Dyna-Gro's Foliage-Pro in the 9-3-6 formulation, and I don't use gypsum or Epsom salts in the fertilizer solution.

If there is interest, you'll find some of the more recent continuations of the thread at the links below:

Post XVIII

Post XVII

Post XVI

Post XV

Post XIV

If you feel you were benefited by having read this offering, you might also find this thread about Fertilizing Containerized Plants helpful.

If you do find yourself using soils you feel are too water-retentive, you'll find some Help Dealing with Water Retentive Soils by following this embedded link.

If you happen to be at all curious about How Plant Growth is Limited, just click the embedded link.

Finally, if you are primarily into houseplants, you can find an Overview of the Basics that should provide help in avoiding the most common pitfalls.

As always - best luck. Good growing!! Let me know if you think there is anything I might be able to help you with.

Al

This post was edited by tapla on Tue, Apr 29, 14 at 23:23

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clipped on: 06.07.2014 at 08:23 am    last updated on: 06.09.2014 at 10:16 am

Trees in Containers III

posted by: tapla on 04.06.2011 at 05:33 pm in Container Gardening Forum

This is a continuation of the second thread on the same topic, both having topped out at 150 posts. You can find a link to the previous thread and the helpful information/conversations it contains at the bottom of this post.

Trees in Containers
A discussion about maintaining trees in containers over the long term

It's not much of a secret to many, that a good part of what I've learned about plants and plant-related science has come as an outgrowth of my pursuit of at least some degree of proficiency at bonsai. Please, make no mistake, the principles applied to containerized trees under bonsai culture can, and in most cases SHOULD be applied to all containerized trees grown for the long term. Because of the small volumes of soil and small containers these trees are grown in, you might look at bonsai as a form of container culture taken to another level. Before most of the plants I grow become bonsai, they often undergo many years of preparation and manipulation while still in the same size containers you are growing in, so while I am intimately familiar with growing plants in bonsai culture, it would have been impossible for me to arrive at that familiarity w/o an even more thorough understanding of growing woody plants in larger, pre-bonsai size containers like you grow in. This thread is a continuation of one I previously posted on the same topic.

I grow and manage a wide variety of temperate trees and shrubs, both deciduous and conifers, and 75 or more tropical/subtropical woody plants. I'd like to invite you to join the discussion with questions about your own containerized trees and/or your tree problems. I will try to answer your questions whenever I can.

The timing of certain procedures is closely related to energy management, which gets too little consideration by most growers tending trees in containers. Because repotting and root pruning seem to be most misunderstood on the list of what it takes to maintain trees that will continually grow at close to their genetic potential, I will include some observations about those procedures to open the discussion.

I have spent literally thousands of hours digging around in root-balls of trees (let's allow that trees means any woody plant material with tree-like roots) - tropical/subtropical trees, temperate trees collected from the wild and temperate nursery stock. The wild collected trees are a challenge, usually for their lack of roots close to the trunk, and have stories of their own. The nursery stock is probably the closest examples to what most of your trees are like below the soil line, so I'll offer my thoughts for you to consider or discard as you find fitting.

I've purchased many trees from nurseries that have been containerized for long periods. Our bonsai club, just this summer, invited a visiting artist to conduct a workshop on mugo pines. The nursery (a huge operation) where we have our meetings happened to have purchased several thousand of the mugos somewhere around 10 - 12 years ago and they had been potted-up into continually larger containers ever since. Why relate these uninteresting snippets? In the cases of material that has been progressively potted-up only, large perennial roots occupied nearly the entire volume of the container, plant vitality was in severe decline, and soil in the original root-ball had become so hard that in some cases a chisel was required to remove it.

In plants that are potted-up, rootage becomes entangled. As root diameters increase, portions of roots constrict flow of water and nutrients through other roots, much the same as in the case of girdling or encircling roots on trees grown in-ground. The ratio of fine, feeder roots to more lignified and perennial roots becomes skewed to favor the larger, and practically speaking, useless roots.

Initial symptoms of poor root conditions are progressive diminishing of branch extension and reduced vitality. As rootage becomes continually compressed and restricted, branch extension stops and individual branches might die as water/nutrient translocation is further compromised. Foliage quality may not (important to understand) indicate the tree is struggling until the condition is severe, but if you observe your trees carefully, you will find them increasingly unable to cope with stressful conditions - too much/little water, heat, sun, etc. Trees that are operating under conditions of stress that has progressed to strain, will usually be diagnosed in the end as suffering from attack by insects or other bio-agents while the underlying cause goes unnoticed.

I want to mention that I draw distinct delineation between simply potting up and repotting. Potting up temporarily offers room for fine rootage to grow and do the necessary work of water/nutrient uptake, but these new roots soon lignify, while rootage in the old root mass continues to grow and become increasingly restrictive. The larger and larger containers required for potting-up & the difficulty in handling them also makes us increasingly reluctant to undertake even potting-up, let alone undertake the task of repotting/root-pruning which grows increasingly difficult with each up-potting.

So we are clear on terminology, potting up simply involves moving the plant with its root mass and soil intact, or nearly so, to a larger container and filling in around the root/soil mass with additional soil. Repotting, on the other hand, includes the removal of all or part of the soil and the pruning of roots, with an eye to removing the largest roots, as well as those that would be considered defective. Examples are roots that are dead, those growing back toward the center of the root mass, encircling, girdling or j-hooked roots, and otherwise damaged roots.

I often explain the effects of repotting vs potting up like this:

Let's rate growth/vitality potential on a scale of 1-10, with 10 being the best. We're going to say that trees in containers can only achieve a growth/vitality rating of 9, due to the somewhat limiting effects of container culture. Lets also imagine that for every year a tree goes w/o repotting or potting up, its measure of growth/vitality slips by 1 number, That is to say you pot a tree and the first year it grows at a level of 9, the next year, an 8, the next year a 7. Lets also imagine we're going to go 3 years between repotting or potting up.

Here's what happens to the tree you repot/root prune:
year 1: 9
year 2: 8
year 3: 7
repot
year 1: 9
year 2: 8
year 3: 7
repot
year 1: 9
year 2: 8
year 3: 7
You can see that a full repotting and root pruning returns the plant to its full potential within the limits of other cultural influences for as long as you care to repot/root prune.

Looking now at how woody plants respond to only potting up:
year 1: 9
year 2: 8
year 3: 7
pot up
year 1: 8
year 2: 7
year 3: 6
pot up
year 1: 7
year 2: 6
year 3: 5
pot up
year 1: 6
year 2: 5
year 3: 4
pot up
year 1: 5
year 2: 4
year 3: 3
pot up
year 1: 4
year 2: 3
year 3: 2
pot up
year 1: 3
year 2: 2
year 3: 1

This is a fairly accurate illustration of the influence tight roots have on a woody plant's growth/vitality. You might think of it for a moment in the context of the longevity of bonsai trees vs the life expectancy of most trees grown as houseplants, the difference between 4 years and 400 years, lying primarily in how the roots are treated.

I haven't yet mentioned that the dissimilar characteristics of the old soil as compared to the new soil when potting-up are also a recipe for trouble. With a compacted soil in the old roots and a fresh batch of soil surrounding the roots of a freshly potted-up tree, it is nearly impossible to establish a watering regimen that doesn't keep the differing soils either too wet or too dry, both conditions occurring concurrently being the rule rather than the exception.

Most who read this would have great difficulty showing me a containerized tree that's more than 10 years old and as vigorous as it could be, unless it has been root-pruned at repotting time; yet I can show you hundreds of trees 20 years to 200 years old and older that are in perfect health. All have been root-pruned and given a fresh footing in in new soil at regular and frequent intervals.

Deciduous trees are some of the most forgiving of trees when it comes to root pruning. The process is quite simple and the long term benefits include best opportunities for plants to grow at or near their potential genetic vigor, and stronger plants that are able to resist the day to day perils that bring down weaker plants. Root-pruning is a procedure that might be considered borrowed from bonsai culture, but as noted above, bonsai culture is nothing more than highly refined container culture, and to restrict the practice of root-pruning to bonsai only, is an injustice to those of us who simply enjoy growing trees in containers.

Trees are much like human beings and enjoy each other's company. Only a few love to be alone. ~Jens Jensen

Now that I have made the case for why it is important to regularly perform full repots (not to be confused with potting-up) and prune the roots of your containerized trees regularly, I will offer some direction. Root-pruning is the systematic removal of the largest roots in the container with emphasis on removal of rootage growing directly under the trunk and at the perimeter of the root mass.

Root pruning can start immediately with year-old seedlings by removing the taproot just below the basal flare of dormant material, repotting, and treating the plant as a cutting. This will produce a plant with flat rootage that radiates outward from the base and that will be easy to care for in the future.

Young trees (under 10 yrs old) are nearly all dynamic mass and will tolerate root-pruning well. Most deciduous trees are extremely tolerant of root work. Acer buergerianum (trident maple) is routinely reduced to a main trunk with roots pruned all the way back to the basal flare and responds to the treatment with a fresh growth of fine, fibrous roots and a fresh flush of foliage each spring. The point here is, you don't need to be concerned about the pruning if you follow a few simple guidelines.

First, some generalities: undertake repotting of most deciduous material while the plant is quiescent (this is the period after the tree has met its chill requirement and has been released from dormancy, but has not begun to grow yet because of low soil temps). Most conifers are best repotted soon after the onset of spring growth. Most tropical and subtropical trees are best repotted in the month prior to their most robust growth period (summer). Citrus are probably best repotted in spring, but they can also be repotted successfully immediately after a push of top growth.

For most plants that have not been root-pruned before: With a pruning saw, saw off the bottom 1/3 of the root ball. With a hand-rake (like you use for scratching in the garden soil) and/or a wooden chopstick and/or the aid of water under high pressure from a garden hose, remove all the loose soil. Using a jet of water from the hose and the chopstick, remove the remaining soil - ALL of it. The exception here would be those plants that form dense mats of fine roots (citrus, bougainvillea, rhododendron ...). This should be done out of sun and wind to prevent the fine roots from drying. 5 minutes in the sun or wind can kill fine roots & set the tree back a week or more, so keep roots moist by misting very frequently or dipping the roots in a tub of water as you work. After the soil is removed, remove up to another 1/3 of the remaining mass of roots with a sharp pruning tool, taking the largest roots, and those roots growing directly under the trunk. Stop your pruning cuts just beyond where a smaller root branches toward the outside of the root you are pruning. Be sure to remove any J-hooked roots, encircling/girdling roots or others exhibiting abnormal growth.

Before you begin the pruning operation, be sure you have the soil & new container ready to go (drain screens in place, etc). The tree should fit loosely inside the walls of the container. Fill the container with soil to the desired ht, mounded in the center, & place tree on the mound. Add soil to cover roots & with a chopstick/skewer, or sharpened wood dowel, work soil into all voids in the roots, eliminating the air pockets and adding soil to the bottom of the basal root-flare. Temporarily securing the tree to the container with twine or small rope, even staking, against movement from wind or being jostled will fractionalize recovery time by helping to prevent breakage of newly-formed fine rootage. Place the tree in shade & out of wind until it leafs out and re-establishes in the container.

The first time you root-prune a tree will be the most difficult & will likely take up to an hour from start to finish, unless the tree is in larger than a 5 gallon container. When you're satisfied with the work, repot into a soil that you are certain will retain its structure until the next root-pruning/repot. Tree (genetic) vigor will dictate the length of time between repots. The slow growing, less vigorous species, and older trees will likely go 5 years between repots. For these slow growing trees, it is extremely important that soils retain aeration. For these trees, a soil of 2/3 inorganic parts and 1/3 organic (I prefer pine or fir bark) is a good choice. The more vigorous plants that will only go 2 years between repots can be planted in a soil with a higher organic component if you wish, but would still benefit from the 2/3 inorganic mix.

Most trees treated this way will fully recover within about 4 weeks after the repot By the end of 8 weeks, they will normally have caught & passed, in both development and in vitality, a similar root-bound plant that was only potted up

When root-pruning a quiescent plant, you needn't worry much about "balancing" top growth with rootage removed. The plant will tend to only "activate" the buds it can supply with water. It is, however, the optimum time to undertake any pruning you may wish to attend to.

This is how I treat most of my trees. Though I have many growing in bonsai pots, more of my plants are in nursery containers or terra-cotta and look very much like your trees, as they await the beginning of intensive training. With a little effort at developing a soil from what's available to you and some knowledge and application of root-pruning and repotting techniques, I'm absolutely sure that a good % of those nurturing trees in containers could look forward to results they can be very pleased with. This is the repotting technique described that allows bonsai trees to live for hundreds of years & be passed from generation to generation while other containerized trees that have not had their roots tended to, and have only been potted-up, are likely to be in severe decline, or compost, well before they're old enough to vote. ;o)

I hope you're bold enough to make it a part of your containerized tree maintenance, and I hope what I've written so far makes sense. Thank you so much for your interest.

Al

Knowing grass, I understand the meaning of persistence.
Knowing trees, I understand the meaning of perseverance.
Knowing bonsai I understand the meaning of patience. ~ Al

If interested, follow the embedded link to the previous discussion about trees in containers.

NOTES:

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clipped on: 06.07.2014 at 11:01 pm    last updated on: 06.07.2014 at 11:01 pm