Asked February 16, 2015, 4:00 PM EST
My name is KC from Kellner greenhouses in Milwaukee WI. We sell organic plants for gardening and we are always looking for new products for our customers to use in there gardens for fertilizer and amendments. Do you have any suggestions on what organic amendment perhaps with live microbes to use in ones garden. We currently use one product but are looking for more to sell in our retail area for customers to add to there garden beds. We currently suggest for them to use there own compost, worm casting, bone meal, etc........
thanks for your time,
Milwaukee County Wisconsin
Thank you for contacting us. This is a bit awkward for me, because I am a Master Gardener and cannot recommend products, per se. So I will give you the information I have. If you would like a response from another writer, let me know and I will pass your question on.
Mycorrhizae are essential, however they are also ubiquitous. Compost and healthy soils naturally contain mycorrhizae. There are many different kinds (2000 or more), and many are plant-specific. Those which are introduced to a soil environment that does not provide the proper plant associations and other requirements will simply die out. The best explanation I have found is here: http://www.uaf.edu/files/ces/publications-db/catalog/anr/HGA-00026.pdf) This article indicates that it would be very difficult to harvest and distribute mycorrhizae that are beneficial to herbaceous plants or vegetables. It may be somewhat easier for trees and shrubs.
While not scientific, here is another article that provides a good, but less technical, explanation: http://www.lawn-care-academy.com/microorganisms-in-soil.html.
In my opinion, the best product is a balanced and mature compost. With the possible exception of creating a new bed, compost is best applied on the surface of the soil rather than tilling it in. (This is because the decomposer organisms use nitrogen, and may cause a temporary shortage of nitrogen at the level of plant roots.)
I hope this information is useful. Again, if you wish to have another response, please let me know.