Split discussion from this thread: Pawpaw (Asimina triloba) - #15 by malterod
Bio-inoculants seem like one of those garden myths that are spread especially by people who have something to sell. Linda Chalker-Scott has done several reviews of the science and sums up some of it in this paper.
It seems like just about everybody has something to sell, even if it is in the realm of ideas. Im not at all talking about pre packaged bio-inoculants here. I agree that those are mostly a waste of time and money. What I am talking about is IMO’s found in our immediate environments, which could help pre-program whatever seeds we want to plant. In this case my inspirations are coming from people such as John Kempf, Dan Kittredge, Dr. James White, Dr. Christine Jones, and others.
As for someone having something to sell, I think of that in the literal sense. Many scientists have their passions and they defend their ideas sometimes at the cost of seeing the truth. Hence why great studies have guard rails against those kind of biases - controlled samples, blinded experimenters, and lots of reproduction of those studies. When I look at a lot of the popular names in the regenerative agriculture movement (of which I think of myself as part of), I see people who sell books, courses, consultations and sometimes even products to add to your soils. When I hear claims on soil science, microbiology and plant physiology that clashes with mainstream science, my internal warning bell starts ringing.
The understanding I have gotten from Chalker-Scott’s review is that inoculating soils clashes with a lot of what we know about microbes. For example, most of them are literally everywhere: fungal spores, bacteria etc. The limiting factor is not whether they are present or not, but whether the environment furthers their growth. I hear the same thing from people who want to grow mykorrhizal fungi in their garden - they try to inoculate their soil with cep or chantarelle mycelium. I never hear the most respected mycologists doing that kind of stuff. They know the space is not vacant and has already been taken up by other fungi and microbes. I realize this discussion probably merits its own thread and I have a responsibility in derailing here. If you want certain microbes in your soil, the science seems to recommend changing the environment - e.g. with mykorrhiza you can allow more mulching and disturb the soil less.
There’s one exception where it does make sense to inoculate and that is containers with sterile growing mediums - Mycorrhizae! Myco what?? – The Garden Professors™