Commonly, each species of plant has a general range of cold-hardiness. Within species and cultivar, cold-hardiness is genetically determined. That is to say that a plant that is propagated from cuttings or tissue culture will have the same ability to resist cold as the parent plant. Plants cannot "develop" a greater degree of cold-hardiness by repeated or prolonged exposure to cold, even after 100 years (trees).

If we pick any plant at random, it may or may not be able to withstand freezing temperatures. The determining factor is the plants ability to prevent freezing of bound water. Bound water is the water inside of cells.

There are actually three kinds of water to consider when we discuss "freezing". The water held in soil - When this water freezes, and it can freeze the soil mass solid, it doesn't necessarily kill the plant or tissues. Then there is free or unbound water, also called inter-cellular water. This is water that is found in plant tissues, but is outside of living cells cells. This water can also freeze solid and not kill the plant. The final type of water is bound water or intra-cellular water. If temperatures drop low enough to freeze this water, the cell/tissue/plant dies. This is the freeze damage that kills plants.

Fortunately, nature has an antifreeze. Even though temperatures drop well below freezing, all plants don't die. In hardy plants, physiological changes occur as temperatures drop. The plant moves solutes (sugars, salts, starches) into cells and moves water out of cells to inter-cellular spaces in tissues. These solutes act as antifreeze, allowing water in cells to remain liquid to sometimes extremely low temperatures. The above is a description of super-cooling in plants. Some plants even take advantage of another process to withstand very low temps called intra-cellular dehydration.

The roots of your trees can stay frozen for extended periods or go through multiple freeze/thaw cycles w/o damage, so long as the temperature does not fall below that required to freeze intra-cellular water. If roots remain frozen, but temperatures remain above killing lows, dessication is the primary concern. If the tree is able to take up water, but temperatures are too low for the tree to grow and make food, stored energy becomes the critical issue. Dormant and quiescent trees are still using energy from their reserves (like a drain on a battery). If those reserves are depleted before the tree can produce photosynthesizing mass, the organism dies.

There are a number of factors that have some affect on the cold-hardiness of individual plants, some of which are length of exposure to seasonal cold, water availability (drought stressed plants are more cold tolerant), how recently planted/repotted, etc

No one can give a definitive answer that even comes close to accurately assessing the temperature at which bound water will freeze that covers the whole species. Unbound water is of little concern & will usually freeze somewhere around 28*.
Some material will be able to withstand little cold & roots could freeze/die at (actual) root temperatures as warm as 25-27*. Other plants may tolerate much colder actual root temperatures - as low as 10*. There's just no way of knowing unless you have a feeling for how cold-tolerant the genetic material the plant was derived from might be, and finding out is expensive (from the plant's perspective). ;o) Another example of this genetic variance is that trees found growing and fruiting well closer to the equator need no chill time, while other trees, derived of genetic stock from a more northerly provenance may need a period of chill to grow with optimum vitality in the subsequent growth period/cycle.

It's wise to remember that root death isn't instantaneous at one particular temperature. Roots succumb to cold over a range of chill with cultural conditions affecting the process. The finest roots will die first, and the slightly thicker and more lignified roots will follow, with the last of the roots to succumb being the more perennial and thickest roots.

Since any root death is a setback from an energy allocation perspective, and root regeneration takes valuable time, it's probably best to keep actual root temperatures in the 25-40* range as long as we can when the tree is resting, even though the organism as a whole could tolerate much lower temperatures. Even well established trees become very much like cuttings if all but the roots essential to keep the tree viable are lost to cold. Regeneration of roots is an expensive energy outlay and causes the trees to leaf out later than they normally would and shortens the natural growth period and reduces the potential increase in biomass for the next growth cycle and perhaps beyond.

Al

I use this mix in all my containers, and it works really well for me. I even got a half-dozen kinds of seeds to start outside in it this year (this was a big achievement for me). I don't sift the DE, I just dump it in with the rest and stir, and water my plants with diluted hydroponic fluid sometimes (when I think of it).

I'm sure some of the more experienced gardeners are cringing at all of the things I'm doing wrong, but somehow my plants thrive. :-)

FWIW - I don't remember exactly what I started with in my RBs, but it was probably something like
5 pine bark
2 Michigan (reed/sedge) peat
1 sphagnum peat
2 play sand
2 Turface

I included some micro-nutrient powder and a charge of 27-3-3 fertilizer, too.

The more organic matter you use, the greater the shrinkage. Compost will literally disappear to nothing over 5 years or so, you'll need to keep replenishing it. There are other problems associated with almost all fine organic matter too, so I think you should be thinking in terms of at least a 50-60% mineral fraction (topsoil, sand, Turface ......), unless you use pine bark - then you can use less.

In raised beds, the organic matter promotes lots of soil life, which helps with aeration and guards against compaction. In containers, soil biotic populations are tenuous, and you water far more often than you do in raised beds. Also, if you use the fine particulate matter in containers, it supports high PWTs that kill off the soil organisms, so you don't get the same benefit.

If your container mix is compost and perlite, it will be extremely water retentive, unless the perlite is at least a 60-70% fraction of the mix. That's why I say you can't amend compost to make it drain properly. Once compost is less than 50% of the mix, you're using compost to amend the other ingredient(s).

Finished compost is primarily lignin and some lipids, neither of which decompose all that quickly. The problem with compost in containers isn't necessarily that it breaks down so quickly, it's the small particulate size that supports excess water retention. If you decide to water in small sips to compensate for the water retention issue, you guarantee that soluble salts will accumulate in the soil unless you take regular steps to flush it.

Again, it's not that you CAN'T grow in a soil based on compost, but it's much more difficult, your decisions are much more critical, and the margin for grower error is much narrower than if you were using a durable and well-aerated mix.

Al

Also, it might be good to give the pots a drench for root mealybugs. Lift the plants out of the pots to inspect for small white splotches, also to examine the population of stolons winding around the rim. The latter is where much of the spring growth will originate. These will be the most frost sensitive parts of the plant.

The 'black and blue' and 'blue ensign' are both salvia guaraniticas and you won't find any seed for them. Unlike salvia coccineas like 'lady in red' and 'coral nymph', the guaraniticas don't produce much seed and also tend to not come true from seed. 'Black and blue' plants can often be found at local garden centers and online. 'Blue ensign', which Steve will tell you is an even better hummer attractor than 'black and blue', can be bought online from A World of Salvias. I am likely going to buy a couple of them later this spring.

Anyway, I thought I'd list the flowers that have definitely been visited, and also list the ones that I thought would work, but don't seem to be getting any action. I have other flowers that I won't mention, because I don't think they are known to be attractive to hummingbirds.

THESE ARE GETTING(OR GOT)VISITED:
Bleeding Hearts--Not sure of genus and species, probably just the common one.
Native columbine--Aquilegia canadensis
Scarlet Sage--Salvia coccinea
Bee Balm--Monarda didyma "Gardenview Scarlet" with bad case of mildew
Fuchsia "Billy Green" I'm not sure if they're exploring or actually feeding
Trumpet Vine--Campsis radicans var. "flava"

I must say, the Bee Balm is probably their favorite, with trumpet vine second. I haven't gotten a clear look at the Fuchsia, but I'm pretty sure they're using it. These three flowers are getting visited, even when the feeders are up. As far as I know, the others were visited only when the feeders were inside for cleaning. Of course, I can't be sure I'm not missing visits, but I'm a pretty patient observer, and this is what I've observed.

THESE DO NOT SEEM TO BE GETTING VISITED:
Petunias--bright red ones
Verbenas--annual ones, red with white centers
Verbenas--perennial ones "Homestead Purple"
Lobelia speciosa "Fan blue"
Zinnias--Pom pom ones and cactus-flowered ones
Snapdragons--Mixed colors in planters, traditional shaped blooms
Impatiens--shades of red, magenta, and pink. Don't know species, but they're the regular annuals you see everywhere, not the New Guinea ones
Oriental Lilies--Lilium
Daylilies--Hemerocallis--Orange wild-looking ones
Agastache "Pink Panther," and "Big Bazooka"
Cypress Vine--Ipomoea (?)

I must say, I really thought I'd see them at the Impatiens and also the Agastache, but if they're visiting, I've been missing it. The Cypress Vine so far has had only a few blooms at a time, so maybe it's just not a sufficient draw. In the past, I saw hummingbirds exploring my "Casa Blanca" lilies, but so far haven't seen any action at my pale yellow ones.

TOO SOON TO SAY, HAVEN'T BLOOMED YET:
Hardy Hibiscus "Fireball"
Cardinal Flower-Lobelia cardinalis
Cardinal Climber--Ipomoea x multifida

I have high hopes for these, but will just have to wait and see. All are showing signs that they will soon be blooming.

Can anyone else share their experiences?

I asked my local ornithologist from the Sate Audubon Society about adding sugar and she laughingly said, "Sugar to taste, although I have never personally tasted it, therefore I don't add sugar".

I am 62 yrs old and I have been making suet since I was about 6yrs old, but to be totally honest, I don't think i ever made it the same way twice in all that time. There is no absolute recipe, it is basically just a simple project of using whatever you happen to have on hand at the time.

In its simplest state you can get raw suet from a butcher and hang that. The fat that you trim off beef or ham, whether raw or cooked is also excellent just as it is. In fact, after thanksgiving I took all the thick fat from the turkey roaster and made a suet cake with that and it worked great, not to mention that last week I took the raw fat we trimmed off a chicken before cooking and put that in one of my suet cages and that went big with the Red Belly Woodpeckers.

When making suet from Lard, begin by warming the lard just enough to soften it to the consistency of peanut butter (Do not liquify it). You then add in bird seed, peanuts, peanut butter, oatmeal, corn meal, stale cookies crumbs, crunched up potato chips, (especially crunched up stale Fritos), diced pieces of orange or grapefruit rinds, dried fruit or what ever else you may have at hand, there is no specific recipe and it you don't have all those ingredients, no problem, just use what you have. One thing that i have found that works very well is raw cranberries, both whole and dice up bits.

Some people prefer to mix it with a spoon or spatula while others such as myself just dive right in an mix it with my bare hands. Here again, there is no right or wrong way.

I have about 6 of the little plastic trays that commercial suet cakes are packed in, and i use them as mold to make my own suet cake to fit my cage type suet feeders.

You can also form the suet into a ball or log then hang it in a net bag such as the ones used to pack oranges or onions.

To make a suet log you just select a piece of dead wood with the bark still on it and use a drill with a 3/4" to 1-1/2" spade bit (whatever you have handy) and drill some holes about 1" deep, then pack the holes with your suet mix.

Some people add little dowels as perches but I find that the desirable birds that we like to attract to the suet feeders, I.E, Woodpeckers, Titmice, Nuthatches and Chicadee's are all very adept at hanging on tree bark, whereas the less desirable birds, such as starlings and Blue Jays have a bit of difficulty at hanging on the bark.

You can store excess suet cakes in the freezer but at my house freezer space is at a premium. I simply put then in metal coffee cans and set then on a shelf in my garden shed, Which at this time of year, is every bit as cold as my freezer. (The metal cans prevent mice form getting into them.)

Someone in Minneapolis was able to keep Zone 7 plants in his Zone 5 beds by filling various size plastic bags with shredded leaves, and placing them around the perimeter of his flower beds and in the open spaces between plants after fall trimming. The bed was then covered with a sheet of plastic, completing the insulation and forming an in situ cold frame. The cover and the bags were removed sometime in late winter or early spring, when frost penetration of the soil eased off..

Those are so beautiful by the way!

Mike

I was part of the scientific team that did the research to check if the pollen of Bt corn (genetically engineered corn) was harming monarch butterflies. I am also providing support to the lead USDA team on Colony Collapse Disorder of honey bees. So I look at actual objective, uunbiased research and results, not third hand or more media and special interest reports.

1) Only the pollen of one variety of Bt corn had any significant impact on monarch butterfly catapillars at all. That variety was never more than 3 percent of all Bt corn planted. That variety was withdrawn from the market immediately after our results were peer reviewed.

2) Corn only sheds pollen 10-14 days a year. That time of pollen shed rarely if ever overlaps the time that monarchs are migrating through the same area. It requires both toxicity AND exposure to create a problem, so even the insignificant toxicity of other Bt corn does not have the chance to create much in the way of damage. A scientist at the Smithsonian once said, more monarch butterflies are killed by car windshields every summer than by BT corn.

3) Genetically engineered crops have nothing to do the disappearance of honey bees, if for no other reason than the fact that corn, cotton, and rice, the major genetically engineered crops, are all wind- not insect-pollenated.

4) Scientific literature about honey bees has reported similar syndromes to Colony Collapse Disorder about every forty years going back to about the 1880s. So outbreaks from the 1960s, the 1920s and the 1880s all predate any genetic engineering.

5) And by the way, neither cell phones (despite the stupid study in India just reported (I have a list two pages long of the flaws in that study which looked at all of two hives)), nor crops circles, jet contrails, or aliens have anything to do with disappearing honey bees. There are a number of pathogens that have come to North America in the last two years that are probably involved.

By the way since honey bees are inasive foreign insects to North America, are you in favor of wiping tham out?

I'd be happy to provide scientiifc references for the research for anything I've mentioned above.

I sympathize with you if your life is in chaos right now. I've felt the driving desire to run away and live on a tropical island somewhere, anywhere else. But don't add the burden of something you need not make a big deal out of. Focus on taking tiny steps where you can, where you have any control and tell everyone else, you'll discuss their issue next week.

I'll close with a paraphrase of a Chinese parable (and apologize for getting on my soapbox) but when the large tree died and a wise man was told it would take 100 years to grow another like it, he answered "Well then I'd better hurry and plant another one, shouldn't I."

KimKa

When I do a repot, I just leech the soil out (to remove salt build up). Then I take the used soil and throw it in the compost bin.

I'm still nearly dumbstruck!

Al

Each spring, I use a condiment shaker to lightly sprinkle Micromax on the surface of containers I'm not repotting that year, and then scratch it into the surface soil. You can probably get away with skipping this altogether if you're using a fertilizer with all the minors - like Foliage-Pro 9-3-6.

The 5:1:1 mix is in the middle. The other bark samples are all from different suppliers and what I had on hand when I took the pic. The 3 at 3, 6, and 9 are all suitable, especially the 2 at 6 & 9. The one at the top is fir bark and what I use in the gritty mix.

El - use an old shoelace that isn't cotton, or a strip of 100% rayon (man made chamois) or a strand from a 100% rayon mophead. Almost anything that will wick water upward a couple of inches and won't rot is suitable when used for drainage applications. Fold the wick over the blade of a straight slot screwdriver & use that to push it up through the drain hole and into the soil.

I'm grateful for your mentioning you appreciate the info.

Take care, guys.

Al

You're going to have to open the wallet and go get several trays of bedding plants. I think hot pink petunias give a lot of bang for the buck, and if you mix them in with taller orange or yellow inca-type marigolds you'll have a very bright and cheery garden.

Focus on the sitting areas and place the annuals where people are going to congregate. Add some patio planters with dracaena spikes for height, some cheap ivy spilling over the brim and plant thickly with a kaleidoscope of colors and leaf shapes. Make them big and loud.

The gardens which are furthest away from the seating areas don't really need to be dressed up with flowers--they are the background and will do well if they're just simply and neatly pruned. If you do get plants for these areas stick with soft green tints for foliage and dark blue or purple for flowers.

Hope this helps.

T--who has an 80-something MIL and knows just what you are going through. The requests demands never get easier. Sigh.

The pinkish color of the stems in the upper close up hints that it is Floratam variety of St Augustine. You want to keep that stuff. In the lower close up, the stem shooting out to the right shows some indication of a fungus. That may or may not be a problem. The rest looks healthy enough.

Here's how you take care of St Augustine. If you do this, your lawn will look magnificent by Memorial Day.

1. Water deeply when you water but water infrequently. Deeply means 1 inch at minimum (measure with a tuna can). Infrequently means when the grass needs it. This means the soil surface can dry out and get hard as long as the grass still looks good. Keep track of how long it takes before the grass loses its luster. Then subtract a day and water on that schedule. In the hottest heat of San Antonio's summer, I water once a week.

2. WELD your mower to the highest setting (or the highest setting you and your spouse can agree on...which SHOULD be the highest setting). Why weld it? Because one day some well-meaning relative or neighbor will come along and do you a favor by lower it leaving your lawn scalped. St Augustine never needs to be mowed low for any reason. When it grows up tall it becomes very dense and will choke out most all of your weeds including the dandelions. It does have some limitations on that. Oxalis and a few other broadleaf weeds can intrude. Those should be handled as soon as you see them.

3. Fertilize regularly. If you use chemical fertilizers like Scott's, then fertilize after the second time you mow in the early spring. Fertilize again on Labor Day and Thanksgiving. Water it after you use chemical fertilizer to melt the fertilizer and let it wash into the soil. If you use organic fertilizer, you can apply that any time. I use organics on most of the federal holidays. It does not have to be watered in but will start working sooner if you moisten it.

The only problem with St Augustine is that it cannot tolerate no water for months at a time. As long as you water it regularly, it will dominate.

It will take some time mowing at the highest setting before it looks really good. All the grass has to get up to the same height and then you're there.

St Augustine spreads about 10 feet in all directions in a season. All you need is a little bit of it and it will fill in for you.

Newbies often get suckered into buying weed-n-feed products. Don't. If you want to fertilize, buy a fertilizer. If you want to kill weeds, get a spray type product and an adjustable hose end sprayer. Spray the weeds about 2 weeks after you fertilize. Or the Weed Hound is an excellent tool. I bought one a few months ago. Home Depot was the only place that had them.

Here is a picture of the soil in my raised beds:

It's a very productive soil and abundant with all the tiny denizens that make up soil life. You can see it also has excellent tilth. It drains well yet still holds lots of moisture. The soil is comprised (originally) of approx

5 parts partially composted pine bark fines
2 parts sphagnum peat (could also use 2 parts Michigan or reed/sedge peat, leaving out the sphagnum)
1-3 parts Turface or NAPA floor-dry
1-2 parts builders sand or native topsoil
dolomitic lime

but I could easily have used more sand or topsoil in this soil.

Al

Here's the Earthtainer mix process advised by Ray that I worked on the other day. It's a 3:2:1 mix of potting soil, pine bark fines and perlite. The pine bark chips range in size from a dime to a quarter.

From 032110

From 032110

pine or fir bark in 1/8-1/4" size
Screened Turface (may substitute calcined DE, such as NAPA floor dry)
Gran-I-Grit (crushed granite in grower size or #2 cherrystone)
gypsum

Al

I'll provide links to some of the previous nine threads and nearly 1,700 posts at the end of what I have written - in case you have interest in reviewing them. Thank you for taking the time to look into this subject - I hope that any/all who read it take at least something interesting and helpful from it. I know it's long; my wish is that you find it worth the read.

Container Soils - Water Movement and Retention
A Discussion About Soils

As container gardeners, our first priority should be to insure 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. 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 as an 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.

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 Water Movement information.

Consider this if you will:
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 enough nutrients in available form to sustain plant systems. Gas Exchange - It must be sufficiently porous to allow air to move through the root system and by-product gasses to escape. Water - It must retain water enough in liquid and/or vapor form to sustain plants between waterings. 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 of water in 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; in this condition it forms a drop. 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 .125 (1/8) inch.. This is water that occupies a layer of soil that is always 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 perched. The smaller the size of the particles in a soil, the greater the height of the PWT. This water can be tightly held in heavy (comprised of small particles) soils and ‘perch’ (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, and 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. 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: 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 drain better. 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?

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 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 starve/"suffocate" because there is insufficient air at the root zone to insure normal water/nutrient uptake and root function.

Bark fines of fir, hemlock or pine, 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.

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 haven’t 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.

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 ½ BB size I leave it out of soils. Compost is too unstable for me to consider using in soils. The small amount of micro-nutrients it supplies can easily be delivered by one or more of a number of chemical or organic sources.

My Basic Soils
5 parts pine bark fines (partially composted fines are best)
1 part sphagnum peat (not reed or sedge peat please)
1-2 parts perlite
garden lime (or gypsum in some cases)
controlled release fertilizer (if preferred)
micro-nutrient powder, other continued source of micro-nutrients, or fertilizer with all nutrients - including minors

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)
1/2 cup micro-nutrient powder (or other source of the minors - provided in some fertilizers)

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)
micro-nutrient powder (or other source of the minors)

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 vigor closer to their genetic potential. 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, pea stone, coarse sand (see above - usually no smaller than ½ BB size in containers, please), Haydite, lava rock (pumice), Turface or Schultz soil conditioner, 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 pine bark, Turface, and crushed granite.

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
CRF (if desired)
Source of micro-nutrients or use a fertilizer that contains all essentials

I use 1/8 -1/4 tsp Epsom salts per gallon of fertilizer solution when I fertilize (check your fertilizer - if it is soluble, it is probable it does not contain Ca or Mg.

Thank you for your interest.

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

Posting X
Posting IX
Posting VIII
Posting VII
Posting VI
Posting V
Posting IV

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

Al

Good luck! Have fun! ;o)

Mainegrower asks: "Why would you need both granite and Turface in the gritty mix? Both are inert materials which will not break down readily, so I am puzzled about the need for both." As the inorganic fraction of the soil, all Turface would hold too much water for some plants during parts of the growth cycle. All granite would hold no water internally, so would find you watering more than once per day during periods of active growth. Turface has great water retention and granite has poor water retention. By combining them, we get a soil with good water retention that holds no perched water. If we increase the Turface fraction and decrease the granite, we get more water retention. The converse is also true, so combining the two ingredients offers adjustability for water retention with only 3 primary ingredients in the medium as a whole.

There was a lot of thought that went into selecting what I consider to be ideal ingredients for the gritty mix, but you can alter it however you want. The important lesson has always been to work toward a durable, well-aerated soil that holds a ratio of air:water that is as favorable as you can make it with what you have to work with.

"If you're using bark fines which are largely uncomposted, how do you avoid the problem of nitrogen starvation as this component breaks down? You fertilize. I know it sounds simplistic, but you fertilize frequently in these mixes, and soil biota doesn't suddenly "suck" all the N from the soil solution. More importantly, I explain in the OP why pine/fir bark is a very good choice (probably the best?) as the organic fraction of the soils I talk about.

Bark fines of fir, hemlock or pine, 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.

I realize the microbial activity would be much less in the mix than in the ground, but wouldn't it take place eventually? Yes, it does; but because of the low rate at which bark breaks down and the cultural conditions in these soils are generally inhospitable to large populations of soil biota, it occurs very slowly, which returns full circle to your question about N immobilization.

"A commercial Japanese maple grower uses Premier Pro-Mix BRK exclusively for potting. This is 45% peat, 45% composted bark and 10% perlite. This product is not available to me, but he has suggested adding composted bark and extra perlite or Turface to the widely available Pro-Mix BX. I'd be interested in your reaction to this mix and the concept that a fairly large proportion of peat is needed to provide the acidity for JMs." I think there are several holes in the argument. First, it's fallacy that you need any peat in the mix. I just repotted 5 Jap maples last night. I'm off today & will work through at least another dozen - all perfectly healthy and all in a mix with no peat (gritty mix). To further illustrate my point - all those peat soils are limed to provide Ca/Mg, so the pH rises to something just north of 6.0 anyway. Additionally, when the subject is container media, you'll find widespread references that support the fact that media (soil) pH is MUCH less important in container culture than when gardening and mineral soils are the topic. Container culture is much closer to hydroponics than it is to gardening, and it's the media solution pH that is much more important.

If you want low pH (I never give pH much consideration, other than to take a few steps to keep it from rising too much) simply use a fertilizer with urea as it's base (MG, Peters, Schultz ......) or add a little vinegar to your tapwater to help neutralize alkalinity and stop the normal upward creep in pH of aging media.

Finally, if you start with a peat-based mix like you described and add a large pine bark fraction and some Turface (which would just be a substitute for less expensive perlite) then you would pretty much end up with a slight variation of the 5:1:1 mix described in the OP, so YES - go for it. However, you'll find the gritty mix will work better, and it makes things MUCH easier at repot time if you're properly attending to the roots of your trees - fodder for another discussion. ;o)

Al

CONTAINER SOILS AND WATER IN CONTAINERS
Posted by tapla z5b-6a MI (My Page) on Sat, Mar 19, 05 at 15:57

The following is very long & will be too boring for some to wade through. Two years ago, some of my posts got people curious & they started to e-mail me about soil problems. The "Water Movement" article is an answer I gave in an e-mail. I saved it and adapted it for my bonsai club newsletter & it was subsequently picked up & used by a number of other clubs. I now give talks on container soils and the physics of water movement in containers to area clubs.
I think, as container gardeners, our first priority is to insure aeration for the life of the soil. Since aeration and drainage are inversely linked to soil particle size, it makes good sense to try to find a soil component with particles larger than peat and that will retain its structure for extended periods. Pine bark fits the bill nicely.

The following hits pretty hard against the futility of using a drainage layer in an attempt to improve drainage. It just doesn't work. All it does is reduce the soil available for root colonization. A wick will remove the saturated layer of soil. It works in reverse of the self-watering pots widely being discussed on this forum now. I have no experience with these growing containers, but understand the principle well.

There are potential problems with wick watering that can be alleviated with certain steps. Watch for yellowing leaves with these pots. If they begin to occur, you need to flush the soil well. It is the first sign of chloride damage.

One of the reasons I posted this is because of the number of soil questions I'm getting in my mail. It will be a convenient source for me to link to. I will soon be in the middle of repotting season & my time here will be reduced, unfortunately, for me. I really enjoy all the friends I've made on these forums. ;o)

Since there are many questions about soils appropriate for containers, I'll post by basic mix in case any would like to try it. It will follow the Water Movement info.

Water Movement in Soils

Consider this if you will:

Soil need fill only a few needs in plant culture. Anchorage - A place for roots to extend, securing the plant and preventing it from toppling. Nutrient Sink - It must retain sufficient nutrients to sustain plant systems. Gas Exchange - It must be sufficiently porous to allow air to the root system. And finally, Water - It must retain water enough in liquid and/or vapor form to sustain plants between waterings. Most plants could be grown without soil as long as we can provide air, nutrients, and water, (witness hydroponics). Here, I will concentrate primarily on the movement of water in soil(s).

There are two forces that cause water movement 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 pot than it is for water at the bottom of the pot. 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, water’s bond to itself can be stronger than the bond to the object it might be in contact with; in this condition it forms a drop. 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. It will stop rising when the GFP equals the capillary attraction of the fibers in the paper.

There is, in every pot, what is called a "perched water table" (PWT). This is water that occupies a layer of soil that is always saturated & will not drain at the bottom of the pot. 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 equal the GFP; therefore, the water does not drain, it is "perched". If we fill five cylinders of varying heights and diameters with the same soil mix and provide each cylinder with a drainage hole, the PWT will be exactly the same height in each container. This is the area of the pot where roots seldom penetrate & where root problems begin due to a lack of aeration. From this we can draw the conclusion that: Tall growing containers are a superior choice over 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. Physiology dictates that plants must be able to take in air at the roots in order to complete transpiration and photosynthesis.

A given volume of large soil particles have less overall surface area in comparison 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 drain better. We all know this, but the reason, often unclear, is that the PWT is lower in coarse soils than in fine soils. The key to good drainage is size and uniformity of soil particles. Large particles mixed with small particles will not improve drainage because the smaller particles fit between the large, increasing surface area which increases the capillary attraction and thus the water holding potential. Water and air cannot occupy the same space at the same time. Contrary to what some hold to be true, sand does not improve drainage. Pumice (aka lava rock), or one of the hi-fired clay products like Turface are good additives which help promote drainage and porosity because of their irregular shape.

Now to the main point: When we use a coarse drainage layer under our soil, it does not improve drainage. It does conserve on the volume of soil required to fill a pot and it makes the pot lighter. When we employ this exercise in an attempt to improve drainage, what we are actually doing is moving the level of the PWT higher in the pot. This reduces available soil for roots to colonize, reduces total usable pot space, and limits potential for beneficial gas exchange. Containers with uniform soil particle size from top of container to bottom will yield better drainage and have a lower PWT than containers with 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 in the soil for water to be attracted to than there is in the drainage layer.

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 are now employing 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, insert a wick into the pot & allow it to extend from the PWT to several inches below the bottom of the pot. This will successfully eliminate the PWT & give your plants much more soil to grow in as well as allow more, much needed air to the roots.

Uniform size particles of fir, hemlock or pine bark 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 rapidly break down to a soup-like consistency. Bark also contains suberin, a lipid sometimes referred to as nature’s preservative. Suberin is what slows the decomposition of bark-based soils. It contains highly varied hydrocarbon chains and the microorganisms that turn peat to soup have great difficulty cleaving these chains.

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 starve to death because they cannot obtain sufficient air at the root zone for the respiratory or photosynthetic processes.

To confirm the existence of the PWT and the effectiveness of using a wick to remove 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 & allow to drain. When the drainage stops, insert a wick several inches up into the drain hole . Take note of how much additional water drains. This is water that occupied the PWT before being drained by the wick. A greatly simplified explanation of what occurs is: The wick "fools" the water into thinking the pot is deeper, so water begins to move downward seeking the "new" bottom of the pot, pulling the rest of the PWT along with it.

Having applied these principles in the culture of my containerized plants, both indoors and out, for many years, the methodology I have adopted has shown to be effective and of great benefit to them. I use many amendments when building my soils, but the basic building process starts with screened bark and perlite. Peat usually plays a very minor role in my container soils because it breaks down rapidly and when it does, it impedes drainage.

My Soil

I'll give two recipes. I usually make big batches.

3 parts pine bark fines
1 part sphagnum peat (not reed or sedge peat)
1-2 parts perlite
garden lime
controlled release fertilizer
micro-nutrient powder (substitute: small amount of good, composted manure

Big batch:

3 cu ft pine bark fines (1 big bag)
5 gallons peat
5 gallons perlite
1 cup lime (you can add more to small portion if needed)
2 cups CRF
1/2 cup micro-nutrient powder or 1 gal composted manure

Small batch:

3 gallons pine bark
1/2 gallon peat
1/2 gallon perlite
handful lime (careful)
1/4 cup CRF
1 tsp micro-nutrient powder or a dash of manure ;o)

I have seen advice that some highly organic soils are productive for up to 5 years. I disagree. Even if you were to substitute fir bark for pine bark in this recipe (and this recipe will far outlast any peat based soil) you should only expect a maximum of three years life before a repot is in order. Usually perennials, including trees (they're perennials too, you know ;o)) should be repotted more frequently to insure vigor closer to genetic potential. If a soil is desired that will retain structure for long periods, we need to look to inorganic amendments. Some examples are crushed granite, pea stone, coarse sand (no smaller than BB size in containers, please), Haydite, lava rock, Turface or Schultz soil conditioner.

I hope this starts a good exchange of ideas & opinions so we all can learn.

Al

Here is a link that might be useful: Container soil discussion 1