I had someone ask me about this and I gave my long winded answer about photosynthesis, beneficial microorganisms, blah, blah, blah, blah After several minutes I noticed dead air on the other end, I said are you following me and the answer was NO! "I am not a soil biologist and don't understand what you are really saying can you bring it down to a level I can understand and I can explain it to my customers" So I wrote this, (I'm no soil biologist either) lets see if we can beat it up and try to fine tune it so it is really simple. Since this is the organic lawn care section it is tailored to folks using organic methods. Nutrient cycling Grass plants need sun, water and nutrients in the soil to thrive. The sun’s rays provide the means for the plant to turn the sun’s energy into sugars, proteins and carbohydrate (photosynthesis) and store this food in the root. Up to 40% of the food stored in the root is pushed out through openings that feed the good guys in the soil that live there, beneficial microorganisms. Organic matter has a complete line of macro/micro nutrients but they are in forms that are not available to the plant for immediate uptake. These forms of nutrients are non-leechable and do not wash away with rain but are held in the soil until needed. The good guys in the soil love to eat organic matter and through a process called nutrient cycling make these nutrients available to the plant. This process of applying organic matter and supporting the good guys in the soil increases soil fertility which, in turn, increases soil porosity, disease resistance, drought resistance and makes healthy green turf. We support and increase the good guys in the soil by applying compost teas. These compost teas do not contain any animal waste (this is not always true), but are a rich mix of organic nutrients with dense populations of the good guys that live in the soil. The beneficial microorganisms in compost teas populate the root, shoot and soil of the turf and begin a process termed “the soil food web”. The soil food web describes in scientific terms the symbiotic relationship between plants and beneficial microorganisms in the soil. Clay soils have 1000’s of years of nutrients in them, it just that the nutrients are not in plant available forms. By initiating the process of adding organic matter and supporting the good guys in the rhizosphere, the root tips begin to reach deep into the soil increasing the soil tilth and root mass and tapping sources of nutrients that have until now been unavailable to the plant. Synthetic or non organic nutrients The application of synthetic fertilizers to the soil discourages root growth and drought resistance. Think of it this way, if someone was to feed you all of your nutrients needs, eggs, steaks, french fries, etc. in the same place every day why would you ever go somewhere else? Well, OK you have a car but plant roots don’t. As we apply these, immediately plant available, nutrients to the soil, they melt and drop into the top one, maybe two inches of soil. If you ever dig in your yard you will notice that the roots really do not go down that far. Why would they? All of the nutrients are in the top 2 inches of soil. During times of low moisture and high heat, which is known around here as SUMMER, the roots do not penetrate far enough into the soil to be able to reach cooler wetter soils and suffer the consequences. If we begin a program that encourages increased root mass and penetration into the soil we dramatically increase drought resistance and health in turf.