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Things I am learning from working in a greenhouse

posted by: mr_subjunctive on 09.07.2007 at 10:32 am in House Plants Forum

So it's been almost a month now, and I'm kind of settling in. Hated it for a few weeks there, mostly because it was still super hot. I'm getting fonder of it now. So. Submitted for your comment:

-Everybody wants Calatheas except the people who have the right conditions to grow them. Seriously. The *one* (one!) person I've talked to who had the right conditions for Calatheas (a bright, moist bathroom) who was looking for suggestions, when I show her the Calatheas, acted like I'd suggested that she strangle puppies or something. She visibly *recoiled*. I think she wound up leaving with a monkey-puzzle (Araucaria bidwillii) instead, which is just perverse.

-A lot more repotting goes on than I would ever have suspected. I come very close to spending entire days just repotting things.

-People like peace lilies (Spathiphyllum) and jade plants (Crassula) a lot more than I do.

-Venus flytraps (Dionaea) are not cost-effective. We throw away more of them than we sell, and people can't keep them alive at home either, so why bother?

-There should be a law against asking someone else to repot cacti for you. Even if you're paying them to do it.

-If I suggest that a particular plant would be good for someone's conditions, I have just about guaranteed that they are not going to buy one. I have so far steered people clear of untold numbers of Aglaonemas, Ficus binnendijkii, lemon-lime Dracaenas, Philodendrons, and rabbit's-foot ferns.

-Though people will also decline to buy stuff if I tell them that it won't do well where they're wanting to put it, which has saved many ferns, Calatheas, and Stromanthes from untimely deaths.

-I should really figure out how to talk to people about plants in a way that makes them *more* likely, not *less* likely, to buy them.

-Spider mites are an unfortunate fact of life. We don't sell them to you on purpose, and in fact do everything we reasonably can not to sell them to you at all, but even if we succeeded in wiping them out in the greenhouse entirely, we'd just get more of them with the next shipment of new plants and have to start over again. So CHECK YOUR PLANTS CAREFULLY. Though we'll tell you if we see any on something you're buying.

-Agaves and Pachypodiums (Madagscar palm) are bad influences on one another. If you put them side by side, they will plot against you. ("Okay, here's the plan: I'll stab him lightly from one side, and then you get him when he jerks his hand away from me.")

-If you hit them with enough force, Pachypodium thorns will break off in your skin and fester for days.

-Far, far too many people out there water on a schedule.

-Everybody wants to know what living stones (Lithops) are; nobody actually goes so far as to buy one.

-It is sometimes possible to find really cool plants (holly ferns, strawberry begonias) happily growing on the greenhouse floor in a quarter-inch layer of dirt. In which case they're free.

-We will attempt (non-guaranteed) plant rescues, for a fee. (I did not know this before I started working there.)

-Somebody could make a killing calling Dracaena sanderiana "variegated Lucky Bamboo" and selling it in water, but for some reason nobody does. (Is the Lucky Bamboo thing over yet?)

-People are sometimes ridiculously specific about what they want. I've been snapped at for not having chrysanthemums in the right shade of orange. ("The sign says 'bronze.' I don't see any 'bronze' here, do you?") Which, okay, been there myself, but holy crap, people -- if we don't have it, we don't have it, and I can't make it appear out of thin air for you so just go someplace else already, if that's what you're going to do, but leave me out of it. Chrysanthemums aren't even my department.

-When people ask questions about pest problems, they are so inarticulate that you have to pull and pull to get any information out of them. ("Uh-huh. And how big are they? Well what do you consider 'not that big?' Can you give me a measurement, maybe? Or a comparison to something? Fingernail? Grain of rice? Grain of salt? Uh-huh. And where are they located on the plant? No, I mean, are they on the top of the leaf, the bottom of the leaf, along the midribs, at the axils . . . oh. Okay. And what do the leaves look like? You know, like, spotty, curly, burnt, dusty, lacey . . . Okay.")

-They're very free with the information that is completely irrelevant, though. ("Oh, you got the plant from your daughter-in-law? And she went to the University here? Well that is -- Accounting degree, you say? Well, so the leaves are kind of curled under -- cum laude? No kidding. Well that *is* impressive. And she gave you the plant six years ago next Tuesday? Fabulous. But so, about these bugs you say you're having . . . Well, but even if you didn't want your son to marry her, they got married anyway, right? Oh, they're getting divorced. Well. That's, uh, too bad? Or wonderful? I guess?")

-If someone comes in who doesn't really seem to have any strong feelings about what they want to buy, but they feel like they should buy something, they'll get either a peace lily or a Dracaena marginata. 9 times out of 10.

-Whether from watering or sweating, I will be soaking, wringing wet basically all day long.

-More people think they can grow Hibiscus than actually can.

-Large bags of slightly wet sand are heavy.

-So are large bags of soil.

-And large clay pots.

-If I don't force myself to take breaks fairly often, I will develop heat exhaustion, and then either faint or vomit.

-Nobody is interested in any form of Swedish ivy (we have: shiny green, dull green, gray fuzzy, white-edged), or wandering Jew (purple heart, purple/silver, pink/green/white, green fuzzy, green shiny) right now.

-Odds are that if you ask an employee, you can have all kinds of cuttings, offsets, greenhouse-floor plants, etc., for free or at least for very cheap. If you just take stuff without asking and we find out, though, don't come back.

-I do not know enough about orchids, cactus, or ferns.

-What people really want to buy is something that will grow in a closet, get six feet tall in a year without being watered or fed and then not grow any further, has attractive, glossy foliage, will produce huge (think: Hibiscus/poinsettia), sweet-smelling (think: jasmine/Hoya) flowers in every color of the rainbow (except green) year-round, and is completely impervious to pests of any kind.

-We don't actually carry anything like that.


The funniest gardening post I've ever had the pleasure of reading!
clipped on: 09.07.2007 at 01:19 pm    last updated on: 09.07.2007 at 01:20 pm

RE: Does citrus require a 'dark' period every day? (Follow-Up #4)

posted by: tapla on 10.13.2006 at 04:36 pm in Citrus Forum

Toni Toni Toni - Please consider what you're saying before you're so free with instruction? "Nope, citrus does not require a number of dark hours. In fact, they need all the light they can get." This kind of stuff can have a real effect on the satisfaction people get from certain aspects of the growth cycle.

Actually, plants have the capacity to "count" the number of hours of light that strikes photosynthesizing surfaces, and leaves are responsible for doing the counting. They contain a protein pigment that's sensitive to light (phytochrome). This pigment occurs in a form sensitive to visible red light and another sensitive to far-red light. Molecules of this pigment convert from one form to the other, depending on the type of light it absorbs. However, during the dark phase, the form sensitive to far-red light gradually reverts to the other form, so the length of dark period, determines the ratio of the two forms. This is how plants "count" the number of hours of darkness, and it is because of phytochrome's conversion from one form to another that the plant is able to detect the end of the dark period.

The meat of the issue is: Only when a plant's darkness requirement is met will the leaves release certain plant growth regulators which travel from the leaves through various tissues to buds, stimulating some of the buds to switch from leaf to flower production. So Toni, if you want flowers/fruit (the aspects of the growth cycle alluded to above), don't forget to turn out the lights ...



clipped on: 10.17.2006 at 06:47 am    last updated on: 10.17.2006 at 06:48 am

RE: Best Soil Mix For 'Sans'? (Follow-Up #1)

posted by: Russ_FLA on 11.17.2003 at 11:48 am in Sansevieria Forum

Hi Lavonn. Actually I find most Sans will grow successfully in almost any kind of mix as long as it drains
well and has some aeration. You can take most anything and
add coarse perlite to it to make it 'crunchy' enough. I'm
mixing Fafard 3 mix with perlite and Turface in about a
2-1-1 ratio. Fafard 3 mix is peat based, with some composted pine bark, little perlite, and a wetting agent.
Turface is a fairly new product that was originally invented
for conditioning baseball diamonds. It's fired calcined
clay, some folks think it's the same as kitty litter, but it
absolutely is not. But looks similar tho. In the past I
have used a crushed brick product with pieces about 1/4 inch
and smaller, mixed with an organic like composed pine bark
or one of the peat based mixes, and some perlite. I've also
used large grained sand before, which works OK. Fine sand
should not be used. If one has access to pumice, available
only in some parts of the west coast, it is ideal mixed with
an organic of some kind. I like to throw in some bone meal when I'm putting a mix together.


clipped on: 09.01.2006 at 10:38 pm    last updated on: 09.01.2006 at 10:38 pm

RE: Whats this Sans? (Follow-Up #1)

posted by: birdsnestsoup on 12.02.2003 at 04:28 pm in Sansevieria Forum

The cylindricas you have already got are probably S. cylindrica v patula which has long leaves that tend to arch outwards rather than stand upright. There is S. cylindrica v cylindrica which stands erect but it is not so common in the trade. My guess (without seeing a picture - hint, hint) is that you may have S. stuckyi which is almost cylindrical but has a slight channel running along the length of the leaf. Its the only other cylindrical leaf Sans I can think of at the moment which attains such a height. Others such as S. schweinfurthii & S. canaliculata are quite cylindrical but do not grow as big.

Hope this is of some help. Anyone else?


clipped on: 09.01.2006 at 10:36 pm    last updated on: 09.01.2006 at 10:36 pm

RE: 'climbing pole for Philo' (Follow-Up #1)

posted by: PlantladyOtt on 08.31.2005 at 03:53 pm in House Plants Forum

Hi Ken,

Wow that pole sounds real nice! UNfortunately I've never seen anything like it nor do I know who would sell one. However,I've used fine 1/4" square wire mesh to make philo poles. You can use two 4" or 6" nursery pots as a template for the diameter. Buy your length of wire at a builder's hardware store, then roll it into a long tube. You can either cut and bend each tiny wire to keep it closed or use some eletrical wire to 'sew' it shut. Then stuff it with peat moss or sphagnum moss and make sure there's enough room at the top to stick the 4" or 6" green nursery pot inside after you've stuffed it. This is so you can pour water down inside to keep the moss moist as the roots will be more prone to grab on there.

HOpe this helps?



clipped on: 08.27.2006 at 08:32 pm    last updated on: 08.27.2006 at 08:33 pm

RE: Superthrive (Follow-Up #6)

posted by: tapla on 01.10.2006 at 08:17 pm in House Plants Forum

I'd heard so much for and against the product that I decided to investigate for myself. Some folks think it great, others find it worthless. I'm in the middle, but haven't seen anything to convince me there are miracles in every bottle. I've posted this before, so apologies for the repeat.

Superthrive or Superjive

The question of the value of Superthrive as a miracle tonic for plants is often bandied about in horticultural circles. Several years ago, after reading claims that range from "I put it on and my plant, which had never bloomed, was in full bloom the next day" to "It was dead - I put Superthrive on it and the next day it was alive and beautiful, growing better than it ever had before", I decided to find out for myself. If you look for information on the net, youll find the manufacturers claims and anecdotal observations, totally lacking in anything that resembles anything like a control. In my experiments, I tried to keep some loose controls in place so that I could make a fair judgment of its value, based my own observations. Here is what I did, what I found, and the conclusions I made about the use of Superthrive:

On four separate occasions, I took multiple cuttings from the same plant. The plant materials I used were: Ficus benjamina, (a tropical weeping fig) Luna apiculata (Peruvian myrtle), Chaenorrhinum minus (a dwarf snapdragon), and an unknown variety of Coleus. In each instance, I prepared cuttings from the same plant and inserted them in a very fast, sterile soil. Half of the cuttings were soaked in a Superthrive solution of approximately 1/2 tsp per gallon of water. The other half of the cuttings were watered in with water. In subsequent waterings, I would water the "Superthrive batch" of cuttings with a solution of 10 drops per gallon and the others with water. The same fertilizer regimen was followed on both groups of cuttings. In all four instances, the cuttings that I used Superthrive on rooted first. For this reason, it follows that they would naturally exhibit better development, though I could see no difference in vitality, once rooted. I can also say that a slightly higher percentage f cuttings rooted that were treated to the Superthrive treatment. I suspect that is directly related to the effects of the auxin in Superthrive hastening root initiation before potential vascular connections were destroyed by rot causing organisms.

In particular, something I looked for because of my affinity for compact branching in plants was branch (stem) extension. Though the cuttings treated with Superthrive rooted sooner, they exhibited the same amount of branch extension. In other words, internode length was approximately equal.

As a second part to each of my "experiments", I divided the group of cuttings that had not been treated with Superthrive into two groups. One of the groups remained on the water only program, while the other group was treated to a 10 drop per gallon solution of Superthrive. Again, the fertilizer regimen was the same for both groups. By summers end, I could detect no difference in bio-mass or vitality between the two groups of plants.

Since I replicated the above in four different trials, using four different plant materials, Im confident in drawing some conclusions as they apply to me and my growing habits or abilities. First, based on my observations, I have concluded that Superthrive holds value for me as a rooting aid, or stimulant if you prefer. I regularly soak the soil, usually overnight, of my newly root-pruned and usually bare-rooted repots in a solution of 1/2 tsp Superthrive per gallon of water. Second, and also based on my observations, I dont bother with its use at any time other than at repotting. No evidence was accumulated through the 4 trials to convince me that Superthrive was of any value as a "tonic" for plants with roots that were beyond the initiation or recovery stage.

The first ingredient listed as beneficial on the Superthrive label is vitamin B-1 (or thiamine). Growing plants are able to synthesize their own vitamin B-1 as do many of the fungi and bacteria having relationships with plant roots, so it's extremely doubtful that vitamin B-1 could be deficient in soils or that a growing plant could exhibit a vitamin B-1 deficiency.

Some will note that I used more of the product than suggested on the container. I wanted to see if any unwanted effects surfaced as well as trying to be sure there was ample opportunity for clear delineation between the groups. I suspect that if a more dilute solution was used, the difference between groups would have been less clear.

It might be worth noting that since the product contains the growth regulator (hormone) auxin, its overuse can cause defoliation, at least in dicots. The broad-leaf weed killer Weed-B-Gone and the infamous defoliant, Agent Orange, that saw widespread use in Viet Nam, are little more than synthetic auxin.

Al Fassezke


clipped on: 06.26.2006 at 11:01 pm    last updated on: 06.26.2006 at 11:01 pm

Container soils and water in containers (long post)

posted by: tapla on 03.19.2005 at 03:57 pm in Container Gardening Forum

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, waters 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 natures 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.



clipped on: 06.26.2006 at 11:00 pm    last updated on: 06.26.2006 at 11:00 pm

What are you potting in?

posted by: JoyR on 12.22.2005 at 01:10 am in House Plants Forum

Hi everyone,

This is an offshoot of another post I had about hard potting soil. Many of you mentioned that you make your own potting mixture and I would like to know what receipies and ratios everyone has. I am going to try making my own in the spring.


clipped on: 06.26.2006 at 10:50 pm    last updated on: 06.26.2006 at 10:51 pm

About Neem Oil

posted by: tapla on 11.07.2005 at 05:33 pm in House Plants Forum

For any that might be interested, I wrote this as an article for our bonsai club newsletter, but it applies to houseplants as well.

Neem extract as an insecticide

In India mainly, but also Asia and Africa, grows a tree all bonsai enthusiasts should be aware of: Azadirachta indica. You are probably already wondering if it makes a good subject for bonsai. Well, yes and no. I don't know enough about the tree's culture to say it makes a good bonsai medium, but it makes a very good bonsai subject. I'll explain: Azadirachta indica is commonly known as the "neem" tree. Extracts from the tree contain azadirachtin, a relatively safe and effective naturally occurring insecticide. Let me preface the following comments by reminding you that the terms "naturally occurring and/ or organic" do not universally mean safe. Pyrethrums, rotenone, and even the very dangerous nicotine are all organics that should be handled with great caution.
Neem extracts, on the other hand are used in a wide variety of cosmetics, as a topical treatment for minor wounds, to treat stomach ailments, as an insecticide in grain storage containers, bins, and bags, and a whole host of other applications. I'll limit this discussion to its use as an insecticide.
Neem works in many ways. It is effective both as a topical and a systemic. It is an antifeedant, an oviposition deterrent (anti-egg laying), a growth inhibitor, a mating disrupter, and a chemosterilizer. Azadirachtin closely mimics the hormone ecdysone which is necessary for reproduction in insects. When present, it takes the place of the real hormone and thus disrupts not only the feeding process, but the metamorphic transition as well. It interferes with the formation of chitin (insect "skin") and stops pupation in larvae, thus short-circuiting the insect life cycle. Tests have shown that azadirachtin is effective in some cases at concentrations as low as 1 ppm.
Neem oil or extract is most often used in an aqueous (water) suspension as a foliar spray or soil drench. Commonly, it is diluted to about a .05% solution, but the suggested ratio for use in bonsai culture is 1 tsp. per quart of warm water. A drop or two of dish soap (not detergent) helps keep the oil emulsified. The mixture is then applied as a mist to all leaf and bark surfaces and as a soil drench to the tree's root system. It should not be applied as a foliar spray on hot days or in bright sun as leaf burn may occur. Remember to agitate the container frequently as you apply and do not mix anymore than you will use in one day. Neem breaks down rapidly in water and/ or sunlight. (Since writing this, I have discovered that a 50/50 mix of water/rubbing alcohol works very well as the vehicle)
Some users of insecticide need to be able to observe the instant results of their efforts in order to be convinced of the effectiveness of their choice.The application of neem derivatives does not provide this immediate gratification. There is virtually no knockdown (instant death) factor associated with its use. Insects ingesting neem usually take about 3 - 14 days to die. Its greatest benefit; however, is in preventing the occurrence of future generations. It is also interesting to note that in studies it was found that when doses were given, purposefully insufficient to cause death or complete disruption of the metamorphic cycle, up to 30 surviving generations showed virtually no resistance/immunity to normal lethal doses.
I have been using neem oil for about 7 years as both a preventative and fixative and have had no insect problems on my bonsai. It is said to be effective for mites, whitefly, aphids, thrips, fungus gnats, caterpillars, beetles, mealy bugs, leaf miners, g-moth, and others. It seems to be fairly specific in attacking insects with piercing or rasping mouth parts. Since these are the pests that feed on plant tissues, they are our main target species. Unless beneficials like spiders, lady beetles, certain wasps, etc. come in direct contact with spray, it does little to diminish their numbers.
Neem oil does have an odor that might be described as similar to that of an old onion, so you may wish to test it first, if you intend to use it indoors. I've found the odor dissipates in a day or two. As always, read and follow label instructions carefully.
Neem oil can be purchased from many of your favorite bonsai suppliers or via the net.


clipped on: 06.26.2006 at 10:30 pm    last updated on: 06.26.2006 at 10:30 pm