Arrow-right Camera

Spokane

Gardening: Earthworms play key role in soil health

Wed., March 15, 2017

Several common garden worms chew their way through some tasty compost getting it ready for the tomato crop in this file photo. (Pat Munts / The Spokesman-Review)
Several common garden worms chew their way through some tasty compost getting it ready for the tomato crop in this file photo. (Pat Munts / The Spokesman-Review)

At my house, the melting snow has grudgingly given back only one area where I can start on my spring chores. It’s a small woodpile that needs sawing up. Even then, many of the logs are still frozen to the ground which means the project is going to take a while.

In the process of pulling frozen branches and wood off the ground to get ready to cut I turned over an old piece of lumber, and lo and behold, up comes a red wiggler worm very much alive and well, wiggling. I was totally amazed.

The fact that the earthworms are already out working is a testament to their importance in the soil food web. This is the integrated web of soil bacteria, fungi, insects, larvae, worms and animals that convert organic matter into humus, plant nutrients and mix it into the sand, silt and clay that we garden in.

This time of year, most earthworms are deep in the soil below the frost line hanging out until the soil begins to warm up. As it does, they will begin moving back up to the soil surface, bringing with them minerals and nutrients from the deep soil layers up to the surface where they will be available to the plants. At the same time, their tunneling creates passages that allow air and water to move down into the soil. Once back at the surface, they will spend the summer converting leaf and organic detritus into readily available plant nutrients and humus.

Research has found there can be between 500,000 to 1 million worms in an acre of soil, depending on the soil’s quality. Each worm can eat its weight each day as it moves through the soil. Given a little rough calculation, if a million worms in an acre of soil could make 700 pounds of worm castings each day, they would create 255,500 pounds a year with a rough value of $306,600. That’s serious fertility.

So how do you create a healthy habitat where the worms can thrive. First, reduce or eliminate soil tilling. Rototillers pulverize the soil and in the process, destroy worms and their tunnel systems. Instead of tilling every spring, consider going to tilling every other year and using mulch and cover crops in between. To plant under this system, use a shovel to dig only where you will plant your seeds. The mulch will help keep the weeds down and moisture in the soil. The mulch becomes food for the worms and helps hold soil moisture in.

Eliminate the use of synthetic fertilizers and chemicals in favor of organics. Synthetic fertilizers create conditions that the worms find irritating. As a result, they will move elsewhere.

It is not necessary to buy worms. Given good habitat, they will show up. If you want to hurry the process a bit, visit your farm friends for a few dozen horse or cow pies. They will come with free worms.



Click here to comment on this story »