Organic Growing from a Microbial Perspective by Tim Wilson


To come to a rudimentary understanding of how organic or natural growing really works, one must cast off previous miscomprehensions from the chemical model, that when we fertilize or add compost or other organic matter, we are feeding plants. This is not the case. With true organics one is feeding the microorganisms in the soil which convert organic nutrients into a form which can be assimilated by the roots of plants. According to studies, there are only a very few plant species capable of absorbing only a very few organic nutrients. Most plants are only capable of absorbing inorganic nutrients which are made that way by microbes which live at the root to soil interface, the rhizosphere. So the idea which you have, that you are feeding your plants when they appear to need nitrogen and you feed an organic fertilizer deemed high in nitrogen, is bogus. You are feeding the microbes which feed the plants.

Chemical fertilizers, mostly derived from petroleum are inorganic and can be absorbed by the roots of plants, however they are pollutants, which can cause a die off of and population change of soil microbes, build up unused residues which run into the water table and, in my opinion, create harmful tissue changes in the plants which humans consume as food and medicine. In addition, I believe, the use of chemical fertilizers promote the incidence of plant pathogens like powdery mildew, erwinia, fusarium, pythium, etc. The grower can end up in a vicious spiralling downward fall as they use one chemical after another to control the effects brought on by the others.

The plant is no passive player in the natural growing game of survival but is the master conductor of this delicately balanced orchestra. The plant receives energy from above the soil in the form of light. This photosynthesis results in the plant’s internal production of carbon. It utilizes this carbon to create and reinforce tissue as it grows, so it is a very valuable commodity. As we all know the plant also requires a form of nitrogen (N) and other macro and micro-nutrients which it receives through the root system. As already stated this N must be in a form which the plant can directly uptake and use, usually a form of ammonia (N). Research has shown that when a plant needs to uptake N from the soil it sends out some of its precious carbon through it’s root system as a feed for bacteria and *archaea which live in the rhizosphere. [* Archaea are prokaryotes indiscernible from bacteria except through specialized testing; usually DNA] There are more complexities involved, such as, that certain plant types attract certain bacteria/archaea types but that is beyond the scope of this portrayal. When the bacterial/archaea population has increased in response to the carbons excreted by the roots, protozoa and bacterial feeding nematodes are attracted to the region, ‘hatch out’ from cysts and eggs respectively and in the case of protozoa multiply rapidly. Protozoa consist of flagellates, amoebae and ciliates. Some protozoa can multiply (divide) every 2 to 4 hours so their numbers can increase in short order. The protozoa and nematodes consume the bacteria/archaea and release, as waste, the ammonia (N) which the roots can then absorb. The multiplication rate of the bacteria/archaea increases in response to this predation and so on. This has been called the microbial loop. Protozoa are particularly good providers as their ‘digestive system’ only utilizes about 30% of the nutrients consumed meaning that roughly 70% is released as the waste which the roots crave. This factor, combined with their short generational time makes them real feeding machines. Undoubtedly there are micronutrients also processed and absorbed in this cycle. There are still many mysteries which research has yet to unfold or are not yet known to this author.