There are in a healthy soil literally hundreds and hundreds of species of soil bacteria, soil fungi, and many other microscopic soil critters. A single tablespoon of healthy soil might contain over a billion beneficial soil microbes!!! The problem is that most of the soils in the home landscapes of America have a very low population of these valuable and important soil microbes.
It is now possible to replenish your soil with these very valuable plant growth helpers. There are products now available, either in powdered or liquid form, that contain dozens of the most important soil microbes. These magical creatures, when in sufficient numbers, perform very important functions for your landscape plants.
Beneficial Soil Bacteria
Among the hundreds of species of beneficial soil bacteria there are groups that will pull nitrogen out of the air in soil and put it into a liquid form that is available to feed plants. When there are sufficient nitrogen-fixing bacteria in a soil, the need for fertilizer goes way down. Other bacteria will decompose organic matter and even break down pesticide residues if they are in your soil. Soil bacteria will actually reduce soil compaction by improving soil structure creating microscopic spaces or rooms in the soil to hold air or water. Some soil bacteria act as police persons and will suppress soil pathogens that could cause disease in your plants, reducing the need to ever use any fungicides.
Beneficial Soil Fungi
While these root fungi are very valuable, there are dozens of other beneficial soil fungi in a healthy soil performing many important tasks. Some fungi will, along with the bacteria, suppress various plant pathogens. Other fungi will produce various natural growth hormones that help plants grow better and have less stress.
Soil Microbe Products
There are a growing number of products on the market that will help restore many of the beneficial soil microbes lacking in the soil in most home landscapes. Some come in powdered form and can be used in that form or mixed with water to be applied as a foliar spray or as a drench directly into the soil around plants. Others are already in liquid form and are used as a foliar spray or as a drench. In addition, there are now machines designed to produce these liquids containing soil microbes. These liquids are a kind of “tea” created from compost, earthworm castings, or microbial powders.
Soil Microbes Need Ongoing Food
While a poor soil can be turned into a healthy soil over time with the addition of these products, there is one other step that must be taken to gain full value of their magic. You must add organic materials of some kind to your soil all year long, every year, The reason is that these beneficial bacteria, fungi, and other microbes need organic material as food for themselves. They do not survive and multiply if you apply them to a soil lacking much organic material and not getting any new organic material. Organic mulches are the most common method for adding organics to your soils. When you prepare beds or plant plants, you can also add some organic material as part of the planting process.
Unfortunately, most of the companies selling these microbial products do not inform you about this critical need to be adding organic materials at the same time as you use these products.
The Bottom Line
While it is not terribly important for you to understand the technical aspects of these soil microbial products, it is important to understand what kind of “magic” they can create among the plants in your yard. Most of these products perform best when applied to your plants every two or three weeks during the main growing season. In the North that means six to eight applications. In South, you can use these products all year long, maybe once a month.
If you do use any of these products you will see a significant difference in your plants. The foliage will be greener and brighter. The flowers will have deeper color and sometimes will be larger. Over time you will be able to reduce your use of fertilizer and water, and you will have much less trouble with pest insects and plant diseases.
You do not have to use there products every year forever. If you are diligent about providing organic materials to your soil every year, the need for adding these soil microbes will go down enough so that after two or three years, you can add these products maybe just once or twice a season.