Earthworms

Earthworms play a vital role in soil health.

Gardeners eager to revitalize their lawns and gardens may spend hundreds of dollars on tools and products designed to improve soil and growing conditions. Although many of these items can be advantageous, gardeners also may want to look to nature’s best garden helpers: earthworms.

It is believed that nearly 3,000 different types of earthworms inhabit the planet. Worms have been around for hundreds of millions of years.

Worms can be seen as bait dangling on fishing lines or as meals for red-breasted robins. But these subterranean dwellers play their biggest role beneath the soil.

Earthworms move through dirt as they search for food. The worms consume particles in the soil, helping to recycle materials like dead leaves, plant parts, decaying animals, and feces. Through their travels, worms also serve to aerate the soil. Worms bring the subsoil closer to the surface and mix it with the topsoil. Earthworms’ castings also help naturally fertilize the areas in which they reside. The slimy mucus that worms leave behind contains nitrogen, which also helps to amend the soil.

The University of Illinois Extension says most earthworms found, particularly in North America, can only grow so long, even though some worms seem like they stretch forever underneath the ground. Depending on the type of worm and how many segments it has, as well as its age and ability to get nutritious foods, worms typically reach only a few inches in length, offers National Geographic. There are some anomalies, however. The Oregon giant earthworm is one of the largest earthworms found in North America, growing to more than three feet in length.

That worm is very rare, however. In 2016, a 16-inch-long earthworm was discovered in England and became part of the collection at the Natural History Museum in London. Some Australian and South American earthworms are known to grow much larger.