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Earthworms, Workhorses of the Garden
by Judith Rogers
by Judith Rogers

I am a freelance garden writer with a weekly column ‘The Gardener’s Corner’ in the Innisfil Scope and quarterly articles in the regional magazine Footprints.

I began a blog to journal my home and garden life at Lavender Cottage. The art of afternoon tea has been a pleasure of mine for years and ‘Tea with Friends’ has become a weekly post with ladies I’ve met through blogging.

August 29, 2010

The common earthworm is one of the most easily recognized critters we find in our lawns and gardens but not many people realize just how much work they do.

Worms are cold blooded with their body temperature determined by the surroundings and they have no eyes, ears or teeth but five hearts. They can average 20-25 cm long and live anywhere from four to eight years in the wild.

Worms are hermaphrodites, they have both male and female sex organs but require another worm alongside to produce offspring. Each sexually mature worm has a swollen slime-like tube about one third along the body where eggs are incubated in a small cocoon. The worm will slide backwards to remove and deposit the cocoon in soil where fifteen or so hungry baby worms will hatch after about three weeks. These babies themselves will be mature enough to breed in only three to four months and since some worms can live a long time, large populations in soil are not surprising. Good garden soil will contain from ten to fifty worms per square foot and they will move tons of soil per year in search of food.

From the soil worms eat bacteria, fungi, nematodes and organic matter. As food moves along inside the worm it is ground up by sand in the gizzard which serves the same purpose as teeth in other animals. The waste excreted is 50% richer in organic matter than surrounding soil and contains many desirable minerals which is why vermicastings (worm poop) are so beneficial as a soil amendment.
Despite the fact that earthworms don’t have any bones and are made up of hundreds of ringed segments, they are quite strong to be able to move through the soil. They are even capable of moving aside rocks six times their weight while constructing their burrows that are approximately two metres deep. Leaf litter and other matter is shredded on the surface then some is pulled into the burrows to decompose. When making tunnels, excess soil is deposited on the surface as are piles of worm castings.

Earthworms are constantly breaking down and mixing the organic material in soil which increases its porosity and water-holding capacity. The tunnels and burrows aerate the soil allowing water to move underground for plants to use or store for later absorption. These little workhorses are one of the best clay busters one could hope for.

In the past gardeners were taught to work compost or other soil amendments into the soil but now know that by spreading a thin layer on top that worms and other small organisms will pull down and work these additions in themselves. Turning the soil over destroys the worm burrows and populations as many are cut into pieces that do not, despite the myth, regenerate into whole worms again.

Rainy days bring worms by the hundreds to the surface to make dodging their wriggling bodies quite the adventure. There are two theories as to why they do this and one is that they would drown in their burrows but even though they breathe oxygen through their skin just like us, they can live in water for a couple of weeks. The other is that since the soil and other surfaces are moist during and after rain, this is the ideal time for worms to mosey about with ease in search of a mate.

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Judith has a lovely blog, and she is a tea granny like me! Donna

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