I think that you might find this article interesting as well. As it comes from Brent, I consider it true to the last comma! LOL Anyway, this should help you. Read under the section "How Plants acquire fertilizer."
http://evergreengardenworks.com/fertiliz.htm
BTW I have never heard that plants mainly acquire nutrients from the leaves. But I, and others, could be wrong as well.
Like everything we do in bonsai it is subject to change. As new and better ideas about how to maximize the results of fertlizing, even this article will become dated as John Naka's book did 15 years later. Of course now we find out that loam is a very benificial part of a bonsai soils makeup, but oh how to get it in there.
The second part of my soil article has to do with fertilizer. The two, soil and fertilizer work hand in hand and is the reason I am combining the two here. Many think that fertilizer is a step that can be taken haphazardly during the year without much emphasis, but keeping fertilizer front and center throughout the years is more important than anything else we do in bonsai.
First lets take a stroll down memory lane and bonsai in its early years. Many of the bonsai books written in English in the last fifty years have alluded to "loam" in the soil. What is loam?
Loam is composted organic matter i.e.; garden loam. Farmers will plant silage crops in between cash crops to plow into the soil to help renew it by composting in the organic matter. Home gardeners have also benefited by adding composted garbage from dinner as well as grass clipping and yearly leaves. Huge amounts of money are spent on home composting devices that will compost leaves in weeks rather than months. Back when I was young, my father would drive to the foothills where the oak trees grew. He would park the pickup near a cattle crossing, a sort of open grate device that allowed cars to pass over but would keep cattle from passing over. The oak leaves would collect under the grate device and compost over many years. My father would shovel this thick black almost spongy material into the back of the truck. Upon arriving home, it would be placed in the home garden and tilled into the earth to help nourish our vegetable garden. Unbelievable material the “oak leaf mold” as my father used to call it. This was something his father did while my dad grew up in Ohio. He brought it out here and I have never known anyone that has ever collected the black gold.
Why was loam important?
Because loam offered the composted organic matter to the soil mix. This was the catalyst that enabled other organic matter to become colonized with beneficial bacteria to breakdown organic fertilizers (mostly used back then) into useable compounds that the roots could use. Without these organics, fertilizer would become unusable and wash out of the pot before being used by the plant. At this point all the organics in the pot used to help breakdown the fertilizer would clog up the pot causing the roots to rot due to being submerged in a pool of water captured in the pot. This anaerobic atmosphere is fast death for a colony of healthy roots. (More on captured water later)
In time, it was believed that a more porous soil mix with inorganic components would keep the soil from clogging up. We were right, it did. The soil is fast draining and water will never pool on the surface even if the water source is left to rain on the surface forever. It continues to run straight thru. The addition of decomposed granite; larger sand particles, lava, haydite, expanded shale, and pumice have gone a long ways towards helping keep the soil friable and fast draining.
One thing was missing
The missing link in the whole soil chemistry was humates. In our zeal to remove the soil clogging organics in our bonsai soil and substitute inorganic last forever particles we lost the ability for the soil to harbor bacteria, and chemicals beneficial to the plant for thriving conditions. These composted materials help to efficiently break down the organic fertilizers into useable compounds, and make them useable for the roots to absorb.
The trick is to get back to a soil medium that is fast draining, yet contains the organic material useful for the tree. At this point, most people have decided that they like the inorganic soils and have spent many years developing recipes that work on specific species and geographical regions.
The secret catalyst
I was introduced to humic acid about four years ago. I came by it in a more sinister way than I really feel comfortable sharing. Lets just say I came by it by accident in my work while investigating a basement that had flooded. Upon finally gaining access, I found that some amazing “farming” was going on behind closed doors. As I gained acceptance and he figured out that I didn’t really care how he made his living, he would go on to share what he was doing to get super human plants fast. Lets face it when growing cash crops time is money…so to speak.
Humic acid was everywhere within the lab. It was used for every step in the process. From making cuttings to forcing buds. The humates were used in conjunction with the specific NPK values to increase yield in whatever step was needed. The problem with this newfound information was that I did not know how to get the humic acid. It wasn’t as if I could go down to the neighborhood pot store and buy the stuff. (I would later find out I was wrong).
I began to look for information about humic acid on the Internet and did indeed find out that this was a very miracle type material. What I found out was that humates are used in farming locations that have very poor soils, especially clay type soils. Clay soil is very poor at holding and releasing nutrients. It has a very low cation exchange capacity (CEC) With the addition of humates to the soil it allows the soil to repolarize thereby allowing the fertilizer ion to bond with the clay soil. A byproduct of the catylistic exchange is that the soil can now hold more fertilizer while also allowing a faster bacteria bed to break down the organic compounds faster and make them more available to the plants roots. Less fertilizer is needed because the clay now holds the fertilizer and the soil does not allow the soil to wash out the fertilizer as it did before.
Nevertheless, I don’t want to add compost to my new draining soil
Humic acid is available in many ways. The easiest way to introduce it is by adding pure humates in the form of leonardite to the soil surface. Leonardite is a mineral mined in a few places around the world. It was laid down during the carboniferous period nearly 350 million years ago. It is black and considered soft coal being nearly 40 percent pure carbon. It can contain as little as 5 percent humic acid to upwards of 80 percent humic acid depending on where it was mined. I have experimented with 40 percent humic so far but have never seen stronger percentages in the USA. The larger percentages seem to be mined in China. The humic acid can also be chemically extracted and sold in liquid form for dilution and used as a soil drench or applied with liquid fertilizer either by soil uptake of applied on the foliage.
University experiments bear out the fact that liquid fertilizers applied with humic acid did improve the plants ability to take in the fertilizer by folier feeding to the point of even surpassing root uptake. An important side note is in a past issue of Bonsai Today, it was noted the poor CEC of Japanese akadama. I am a firm believer in the miracle red balls from Japan but never really understood the reason the soil acted differently with my trees. Further research has shown that Japanese volcanic soil (akadama, kanuma, and huuyga) all contain percentages of humic acid.
Humic acid is not fertilizer. It is just an additive that makes fertilizer work easier, faster and better. Humic acid will still require a full compliment of fertilizers to work properly. I have found that small percentages of humic acid premixed in a good fertilizer to work best. Two of the products I use now are Gro-Power. A fertilizer fully endorsed by Ted Matson. I also use Gro-Power planting tabs. A simple tablet that will sit on the soil like any Japanese fertilizer cake. The bonus is they do not smell and are looked over by pets and rodents. Both of the products are distributed by Kellogg’s fertilizer company, which carries a full list of fertilizer containing differing percentages of humic acid.
Why haven’t we heard about this before?
If you read Bonsai Today many years ago you probably did, you just didn’t know it. In 1997, Michael Persiano along side Chase Rosade wrote an article for Bonsai Today (issue 47) about “super feeding”. The article explains a myriad of fertilizers and concoctions for this super feeding program. The super feeding fertilizer cake recipe contains a product called Roots 2. In the first article, Michael used the dry form powder for his cakes and would go on in a later article to use Roots 2 liquid with iron, Killing two birds with one product. Many people would go on the use that recipe for making cakes thinking they were super feeding not knowing that if they didn’t include the Roots 2 (which was/is hard to find) they were not adding the humic acid part of the formula. Michaels article and subsequent follow up article neglected each time to tell us of the miracle properties of the Roots 2 formula with humic acid. I suspect that all the additional components that were used to add to this chemical cocktail were probably not needed and the Roots 2 alone would have done just as well.
I can’t find this humic acid stuff?
For those of you that can’t find humic acid which can be found in most cities that have a hydroponic store (the place all the pot growers hang out) look to the internet. There are many companies out there that have fertilizers that list humic acid in the contents right on the box. Even Home Depot and Lowe’s will carry at least one product that lists humic acid. Humic acid is really coming on strong in the fertilizer trade and will continue to grow as more is learned and results gathered. For those out there still not finding it you can make it yourself. Garden composters can be made to throw grass clippings and leaves as well as dinner scraps and stuff like banana peels and coffee grounds. This will have to be composted down. I mean really composted, to the point that a hundred pounds of raw material will be only about 20 pounds when done. It will be black and will smell good, like mushrooms. If it smells bad and is really smelling like rotten garbage than it is not composted enough. At the point of decomposition it will have enough humic acid in it to be used for trees. It can be placed in a bucket with water and made into tea which can be used as a soil drench. Remember you still need fertilizer, this is just the humic acid.
Remember that oak leaf mold my dad used to collect? That stuff would be very good to make tea from. Not something you would want to add to your soil mix (although many probably did many years ago) but the tea will do amazing things.
Like many new things that are introduced to bonsai, they are slow to catch on. Many think this is just the new Super-thrive or HB-101 but after 4 years I have had huge success with the products I have been using. It is very inexpensive to try this for yourself. I hope you can and you might thank me for the heads up.
Al