Earthworms in the Garden

August 27, 2007

By Francis Kilkelly

Notice the lowly earthworm, squirming away, going about its everyday business. Simple creatures you may think but they have quite an important use in the garden. Did you know the earthworms are nature’s first gardeners? They don’t exist just for kids to eat and fishermen to use as bait. 

Some Basic Earthworm Facts

Earthworms are present in almost every type of soil but the healthier the soil the greater the numbers. A healthy soil permits lots of air and moisture, both of which are needed by the earthworm for a continued existence. Earthworms have no lungs like you or me but instead breathe through their skin. Their whole skin absorbs oxygen and releases carbon dioxide. They also need moisture to assist them in respiration but too much moisture is not good for them. There are four types of earthworm that you may run into:

Nightcrawlers: 8 to 10 inches long and the fisherman’s favourite.

Garden Worms: 5 to 7 inches long and found commonly in damp soils.

Manure Worms: 4 to 5 inches long and found in manure rich soils.

Red Worms: 3 to 4 inches long and the most commercially available.

Why Earthworms in the Garden?

A garden without earthworms would miss out on all of the great benefits that they bring to it. Their first job is to till the soil by tunneling through it. Tunnels created allow air and moisture to pass easily through the soil, creating a healthy environment for plants. Tunnels retain water that the plants can take up and also hold air to help bacteria break down organic matter within the soil. After digestion earthworms produce excrement about the size of a pin head. This excrement is called “castings” or “vermicompost” and is an excellent soil conditioning material. It improves properties of the soil such as porosity and moisture retention, aids plant growth and helps in the fight against pests and diseases.

Increasing Earthworm Population in the Garden

How does one go about increasing the number of earthworms in their garden soil? Well the best way to do so is to add more organic matter to the soil. Earthworms cannot get enough of the stuff and will seek it out wherever they can find it.

Finally…The earthworm is just as important to the garden as the gardener that maintains it because they till the soil and add a soil conditioner in the form of castings. They are as much a gardener as you are. The next time you see one wiggling on the ground in front of you bend down and say “got any good gardening tips?” You never know it may answer.

I will leave the final word to a one Charles Darwin who once had this to say about the earthworm: “The plow is one of the most ancient and most valuable of man’s inventions; but long before he existed, the land was in fact regularly plowed and still continues to be thus plowed by earthworms. It may be doubted whether there are many other animals which have played so important a part in the history of the world, as have these lowly organized creatures.”

Francis Kilkelly runs a popular home and gardening community at GardenStew.com, containing gardening forums and gardening blogs.