Extension Educator, Horticulture
Let's face it. Soil is underrated, underappreciated and for the most part "over-ignored" by most people. The foundation of a good garden is good soil; therefore, the main lesson in gardening is getting to know your soil. First, even though we use the terms interchangeably "soil" is not the same as "dirt". Dirt is the stuff in your vacuum cleaner.
Soil is a dynamic substance consisting of minerals, organic matter, insects, fungi, microbes and gazillions of other small creatures. Soils are home to two or more tons of living things per acre. I'm not sure who did the measurements but one fourth of a teaspoon of fertile soil is reported to contain 62,000 algae, 111,000 fungi, 50 nematodes, and 25 million+ bacteria. Soil can sustain an oak tree for hundreds of years. Just try growing an oak tree in your vacuum cleaner bag.
Thanks to glaciers and prairie plants, we gardeners in Central Illinois inherited great soil. Now it's our job not to screw it up. Feed the soil that feeds your plants. So here are some fertile facts about promoting and protecting garden soil.
Add organic matter such as compost or shredded leaves to the soil surface. Organic matter adds and helps retain plant nutrients in the soil. It improves soil structure so air, water and roots can penetrate easily. To loosen high clay content soils or compacted soils, compost is a better option than sand, perlite, peat moss or vermiculite. Organic matter also helps to retain moisture and promotes beneficial microbes and animals. Organic matter is good stuff and local compost is a great source. Add it to your soil with wild abandon.
Limit use of pesticides and fertilizers. Have a reason. "Just in case" is not a reason.
Don't bare your assets. Soil shouldn't be sun bathing in the nude. Naked soil is prone to wind and water erosion. Best dressed gardens wear a cover of compost, straw, grass clippings, a cover crop, pine needles or shredded leaves.
Keep your big feet out of bed. Develop paths and rows that can easily be reached from the path. Don't compact soil by walking on garden areas.
Never till or dig soil when it is too wet. We all try this and regret it later. If wet soil is worked, its structure (how the soil particles are put together) is destroyed. The result will be clods; not good in men or soil. To determine if it is too wet, squeeze a handful of soil then bounce it in your hand. The soil should fall apart. If it stays in a tight ball, then it is too wet.
Think before you rototill. For many gardeners tilling is more habit than necessity. Before tilling, determine the reason. I would venture that existing gardens seldom need to be tilled. A top-dressing of two to three inches of compost in the fall is just fine. If top-dressing with leaves in fall, add a thin layer of soil or compost on top of leaves instead of tilling them in. New flower or vegetable beds may need tilling; however, consider an alternative of lasagna gardening, layering compost and leaves over sodded areas.
Remember tilling brings weed seeds to the surface where they happily germinate competing with your favorite carrots or marigolds. In addition tilling destroys worm burrows and brings subterranean creatures to the surface to die.
If you are having garden problems, a fall soil test may be useful to determine the percent organic matter, pH, and some nutrient levels. Do a quick search for soil testing labs in your area.
"Essentially, all life depends upon the soil ... There can be no life without soil and no soil without life; they have evolved together." --- Charles E. Kellogg, USDA Yearbook of Agriculture, 1938.