Hello all. I am a newbie to bonsai, but I have experience as a soil fertility consultant. I am a student of Dr. Elaine Ingham and have worked with her for a decade as well as consulting in the agricultural world. I understand that agricultural systems and bonsai horticulture are not the same. Of course when I dove into the bonsai world I kept wondering why no-one talked about the microbiology in plant systems. This was before I discovered and joined Mirai. Watching a video of a pine re-potting with Ryan I was happily surprised to hear him talking about mychorrizal plant association. Then as I wandered down the yamadori path I did take note that folks mostly do recognize this importance, especially in pines. I kept wondering if others have been trying the regenerative methods of Dr Ingham (and others-see Dr. David Johnson’s works as well) in bonsai. I searched “compost extract” and low and behold Dr. Ingham’s appearance on the channel came up as well as the talk with Keisha and Casey of Catalyst Bioammendments. These appearances and associated discussions were around 2019. Since then there has been apparent radio silence in the forum (I admit to not doing an exhaustive search). I noticed in a few comments that Ryan was not very impressed with the results of his compost extract trials (one commentor noted that Ryan used a pretty diluted extract and did not apply often-see comment 4 below). I would like to hear more about this from people who have used or still use compost and compost extracts and teas in their practice. But, before I end I would like to throw out my thoughts on compost and it’s derivatives (teas and extracts) from someone who has made lots and lots and lots of compost (I make small batches for commercial sale):
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Compost shouldn’t be thought of as a fertilizer. There are some soluble nutrients as well as humic and other acids, but not in high levels. It should be thought of more as an inoculum of soil micro-biology. If added in solid form it adds significant organic matter as well.
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all composts are DEFINITELY NOT created equal. In my experience, many commercial composts are worthless as a source of any microbiology other than bacteria. Put a sample of bagged commercial compost under a microscope (a la Dr. Ingham) and all you will see is a ton of bacteria of very little diversity. Put a carefully crafted compost under the same scope and it will be full of a huge diversity of microbiology–nematodes, protozoa, fungi, as well as a diversity of bacteria. The reasons for this are many, but most importantly, are due to (most) commercial compost being a product that attempts to monetize waste-streams from animal agriculture. The materials that comprise these compost usually consist of only two inputs–manure/urine and bedding. The microbiology in any compost comes from the feedstocks you use (as well as some small amount of wind and contact with other materials). When you use only two, one nitrogen and one carbon source, you get very little diversity. Coupled with this is that almost all animal agricultural systems with a waste management problem supplemental feed and this will include mineral supplements which are chemically salts. Often mineral supplements are given at high enough levels that they start showing up in pretty high levels in the manure, and then, their compost. Be very aware of the salt load of any compost you purchase. If you are unsure, send a sample to your local Extension office for testing.
3)There are exceptions to the above description. Keisha and Casey’s operation is one (discalimer-I was a colleague of theirs at Dr. Ingham’s school). I have found that many commercial worm composting facilities produce decent compost. Backyard compost that is made with attention to moisture management and diversity of feedstocks is also usually decent and sometimes really good. If you make your own and are not interested on making sure your compost is hot enough for long enough to kill pathogenic organisms, then you should introduce composting worms into your system–they will take care of the pathogenic organisms. Worms also tend to increase the quality of most composts.
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Experience shows that unless your intent is to build organic matter, compost extracts are the best method of application. It uses far less compost and concentrates the microbes. You can, if possible use it straight. Diluting it only reduces what you are trying to apply. If made well there is nothing toxic in the compost, and it can be applied often.
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Some speculation: Extract use from quality compost in inorganic soils will have minimal effect since the organic matter that is so integral to any microbiological nutrient cycling is absent. Bonsai soils with some organic matter will respond positively. Thoughts? Experiences? Forum discussions I stupidly missed?
Again, I’d love to hear any other’s experience. I personally have had some pretty phenomenal results in my veggie garden with heavy extract applications every two weeks. I have just in-ground planted some Japanese maple, some in grow bags and some in my garden soil with pumice added. I plan to treat half of each with the same method. I am going to do the same with several other varieties when they show up later this spring. We’ll see and I’ll be back with results.