Over 200 years ago Charles Darwin studied earthworms to determine their effects on soil and plants in the garden. He kept worms in pots and glass tanks filled with earth and spent hours studying their behaviour and habits. His book The Formation of Vegetable Mould through the Action of Worms, published in 1881, outlined his earthworm observations. He concluded that “earthworms have played a more important part in the history of the world than most persons would at first suppose.”
Today, Darwin’s sentiments towards earthworms are shared by gardeners everywhere. Master recyclers, expert soil tillers and delicious morsels for birds and wildlife, earthworms help make your garden grow.
There are approximately 4,500 species of worms in the world and of those, 2,700 are earthworm species. Worms are very sensitive to light and when exposed to the daylight, they’ll look for shelter right away. The worm’s mouth has a small protruding lip called a prostomium. As the worm forages for food, the prostomium is used to sense organic material. When food is found, microorganisms soften the food before it enters the worm’s mouth and then a muscular gizzard grinds food particles and other materials such as sand and topsoil.
To move through the soil, earthworms make a trail of slimly mucus that help them slide through the ground. When it rains, worms can often be seen wiggling their way across sidewalks and patios. A common myth is that they come out of the ground to avoid drowning as their borrows fill with water, but worms don’t breath oxygen like we do. It’s believed that worms surface to find a mate.
The worms in your garden
A healthy garden can boast 100,000 worms. These wiggly creatures help aerate, decompact and mix soil as they travel through the ground. Their tilling action also allows water and oxygen to penetrate the soil, and improves soil conditions for beneficial bacteria and other microorganisms. Earthworms are also a good food source for birds and toads. Red wriggler worms are known as the gardener’s worm because the live close to the surface of the soil. Night crawlers are also beneficial to the garden because they borrow deep into the soil to find a home.