Earthworms for Your Garden

Have you ever wondered what the best worms are for your garden? There are many benefits to having them, but which ones can give you the most benefits? This article will shed some light on our wriggly little garden friends and help you understand their benefits.

In North America, we have about 180 species of earthworms, and approximately 4,000 species worldwide. They play a critical role in breaking down and decomposing plants and other organic material in our yard, garden, and compost pile. In their wake, they also leave nutrient-dense waste (called “castings”) which is second to none when it comes to improving your soil.

Earthworms can be divided into three groups, each having unique characteristics. Anecic worms play an important role in soil formation and leaf decomposition by pulling leaves into their deep vertical permanent burros. These are also known as nightcrawlers. Endogeic worms build lateral burrows in the soil and have little effect on the surface as they are the only worms that prefer to eat large amounts of soil rich in organic material. They also play a role in the aeration and decomposition of dead plant roots. Epigeic worms, which include the common red wiggler, live on top of the soil eating rotting organic matter, and have a high rate of reproduction. They are also commonly used in vermicomposting systems.

As much as we love earthworms, some problems can arise in their presence. The biggest complaint that homeowners have is that they create lumpy surfaces in grass and other areas that people prefer to keep level (see photo to the left). On a worldwide level, humans can create issues when we introduce worm species to new places and create an imbalance in the local ecosystems. But, generally speaking, the benefits of native earthworms far outweigh their inconveniences.

What are the main benefits to earthworms? To start, worm castings contain concentrated humus and may contain 5 times more nitrogen, 7 times more phosphorus, and 1000 times more beneficial bacteria than the original soil that helps plants thrive. Worms aid in soil aggregation, creating pores for the movement of air, water, nutrients, and roots. Worms can also eat their body weight in food a day.

So, what are some ways to attract and keep worms? In general, it is recommended to disturb the soil as little as possible because we have learned that we can disrupt the soil food web, release precious carbon, and more. Tilling also harms our earthworms. Reducing or eliminating tilling is a great start to keeping earthworms in your yard or garden. Additionally, covering the soil with mulch and organic matter on the surface will help feed the worms as well as reduce the need for tilling and weeding.

Creating a welcoming place for earthworms in your garden, yard, and compost pile has many benefits that you can’t get anywhere else. These little creatures offer big payoffs if you attract and keep them around. Happy worm farming!