Do you know where your earthworms are?

The earthworm is one of nature's top "soil scientists." The earthworm is responsible for a lot of the things that help make our soil good enough to grow healthy plants and provide us food. Worms help to increase the amount of air and water that gets into the soil. They break down organic matter, like leaves and grass into things that plants can use. When they eat, they leave behind castings that are a very valuable type of fertilizer.

Earthworms are like free farm help. They help to "turn" the soil—bringing down organic matter from the top and mixing it with the soil below. Another interesting job that the worm has is that of making fertilizer. If there are 500,000 worms living in an acre of soil, they could make 50 tons of castings. That's like lining up 100,000 one pound coffee cans filled with castings. These same 500,000 worms burrowing into an acre of soil can create a drainage system equal to 2,000 feet of 6-inch pipe. Pretty amazing for just a little old worm, don't you think?

Having worms around in your garden is a real good sign that you have a healthy soil.  So how do you create an environment that supports all those earthworms?

Earthworms need plenty of organic matter to survive.  Keep your garden soil covered with organic mulch.  You can use grass clippings, shredded leaves or compost.  Mulch works like a blanket for the ground.  It keeps the soil cool and moist in the summer and warm in the winter.  These are ideal conditions for garden worms!

Of course, some of the best ways of increasing earthworm populations is by not harming them.  The overuse of chemical fertilizers or fungicides (including copper-based ones) can be detrimental to earthworm numbers.  Frequent deep tillage will not only expose earthworms to an unwelcoming dry environment and hungry birds, but it reduces their food source by increasing decomposition of ground cover.  Zero-till soils have been shown to have four times as many worms as cultivated soils.  One of the many great things about no-till gardening is that it protects and promotes earthworm populations.

Next time you head to your garden, take a shovelful of soil and count the worms.  If you measure 12"x12"x7"deep, the optimum number of worms should be approximately 60.  If you have 10 or less, your soil does not have a healthy community of the necessary microorganisms.  The number of worms is the best indication of your soil health.