As a young child, I watched and learned from my father as he researched and started a new and unusual hobby about every two years. His interests became mine, and I always wanted to help him or do things myself. As a parent, I now realize his next project always started because I had taken over the hobby at hand and was in his way.
In Michigan, we often had several spring days in a row of gloom and rain that soaked the ground to the point of saturation. On one such squishy night, my father handed me a bucket and flashlight and said, “Go to the park and fill this with earthworms.”
I couldn’t believe what I saw at the park. The ground looked like a scene from the movie Night of the Living Dead. Earthworms were squirming out of the ground everywhere. When I got home, my dad threw a few handfuls of worms over the yard then continued to dump the rest onto his new compost pile.
My dad’s interest in composting became my worm farm. I fed the worms on a daily basis with our kitchen scraps until they grew so big I sold a dozen night crawlers to my principal for a dollar.
But the question remained: Why did my dad throw worms onto the lawn?
Observing earthworms or their castings (the small rounded piles of pulverized dirt mixed with organic matter that have passed through a worm's digestive tube deposited on the lawns surface) on your yard are great indicators that your lawn has a healthy soil food web beneath it.
Go out to your yard after a soaking rain and look. See any signs of worms? Worms visit the surface of your lawn bringing subsoil to the surface, then pull lawn debris into their burrow, ingest it, and grind it up in their gizzards into an organic rich slurry of microorganisms and nutrients.
As worms move through the soil, they deposit castings in their underground burrows. Grass roots easily obtain the benefits of what worms do best - soil conditioning.
Having numerous worms wriggling in your soil is equivalent to owning your own aerator to reduce soil compaction. Their slime even contains nitrogen, the first ingredient listed in fertilizers that stimulates grass to grow.
Remember though, worm castings are only as rich in organic matter as your soil is. Worms will move out of your lawn if certain conditions don’t exist, such as the availability of organic matter, moisture, and other microorganisms in the soil food web.
Top-dressing provides the worms with the organic matter they seek on the surface to pull down into the soil each night.
I’ve top-dressed my lawn two springs in a row with composted fertile soil (Planter Mix) from Green Valley Turf Company. Following the night of a recent rain, I asked myself what I would expect to find if I compared my top-dressed lawn to my neighbor’s fertilized yard?
I predicted if top dressing builds a healthy soil food web, then there would be an abundance of worms or castings on my property and not his. What I discovered, were 25 worms on my sidewalk escaping the saturated soil and only one worm on my neighbor’s.
To wit: A healthy lawn is only as healthy as the soil beneath it.
Worms love great soil. Great soil invites worms to condition the soil beneath the grass. Unfortunately, Colorado soil is poor in organics and rich in clay. But, by adding fertile soil over several seasons to an existing lawn, it's possible to create a thriving worm population that will work for you and your lawn.