Abundant earthworms a sign of healthy soil

I love making compost as much as I love actually putting it in my garden. Last week found me turning my bin of cooking compost. The process of putting the pitchfork in, bending my knees and swinging my torso to drop the load into a new pile reminds me of Tai Chi. I find that practicing fluid, unhurried movements – fork to pile, swing to the new pile, dump the detritus onto the new pile, and then swinging back for another fork load, becomes a spiritual exercise as well as a physical one.

In my mind’s eye, I see a complete ecosystem of organisms, from the tiniest bacteria to the fat earthworms that wriggle in and out of the decaying vegetation. There is a certain thrill to the fact that I am part of the process of this cycle of life…and death.

I can’t see the microscopic bacteria, amoebas, mites and protozoans, but I can see their handiwork as they consume nitrogen and sugars from the green and brown materials I have mixed together in this nature cake. I can see the smoke rise and feel the heat as their billions multiply, die and are consumed by larger, but still microscopic  predators – themselves destined for the same fate by even larger organisms. Composting is one of the most “mindful” activities I can think of. I’m not going to belabor the Zen thing, but you get the idea.

Earthworms begin to populate the pile when it cools. I pick out worm every tenth load or so and throw it into a bucket…not for fishing (although I do like to fish), but to add to the worm population in my vegetable garden. I throw in some rotting vegetation for the worms to eat and hide in while I finish turning the pile.

I turn my pile every week or two, until I’ve got good, rich, dark humus, letting it heat up as bacteria begin to multiply again. I could go on about mesophilic and thermophilic bacteria species that alternately heat and cool the pile, but I’m going to spare you the agony. Just know that as the pile heats up, the worms head for cooler pastures, only to return when the pile cools off again.

Earthworms are fascinating creatures. They eat decaying, green vegetation, apple cores and even coffee grounds. That goes through the enzymes and bacteria in their gut and comes out in rich worm castings, which is a euphemism for… well…you know. The castings are also filled with beneficial bacteria which continues to inoculate the soil long after it has left the worm.

A good population of earthworms in an acre-foot of soil can turn eight tons of soil per year. That’s over 1,613 cubic yards. My small pickup can carry about one cubic yard of soil, so that gives you an idea of how much earthworms work.

I’ve always said that if you have earthworms in your soil, you have good soil. Some experts argue that good soil attracts earthworms, while others say that earthworms make good soil. Either way works for me.

Many of the earthworms found here are not indigenous to North America. Instead, they came from Europe. Early colonists – the Jamestown settlers, the Spanish conquistadores, the French, Dutch and German farmers – unknowingly brought native European worms over in plant soil. Once having breached the ocean, the annelids (that’s a generic name for them) didn’t need human assistance to spread themselves across the continent. In some cases they replaced populations of native worms. In other cases they took over areas that had no worms. In Canada and the Upper Midwest, where glaciers scraped the soil from the rock 10,000 years ago, European worms exploited this niche successfully.

Here in Southeast Texas, scientists tell me that we have abundant populations of European species, as well about a 100 native species. Believe me, I can’t tell the difference, although I have no doubt the worms can.

Charles Darwin was one of the first contributors to the study of earthworms. In fact, he published The Formation of Vegetable Mould through the Action of Worms, with Observations of their Habits, the compilation of years of studying the lowly creature. In fact, the book actually outsold his previous book, On the Origin of Species. Read more about Darwin  and his worm studies here.

Photograph by Cliff Roe Photography
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