By Victoria Lee Blackstone Updated May 28, 2020
Although many types of earthworms are beneficial in vegetable gardens, the best worms for gardens aren’t the biggest ones, such as night crawlers. Smaller red wigglers are indefatigable workers in the garden that condition the soil and fertilize plants. Adding worms to a vegetable garden is a fundamental organic practice that even novice gardeners can master.
Benefits of Worms in Gardens
Just below the soil’s surface is an entire ecosystem that’s teeming with life. As one of the inhabitants of this ecosystem, earthworms provide many benefits to vegetable gardens.
When they eat organic matter, such as fallen leaves as well as soil organic matter, earthworms provide valuable nutrients to plants through the waste they excrete. This excrement also helps bind soil particles together, which helps improve the soil structure. The burrows that earthworms create as they tunnel through the soil provide air pockets that provide oxygen for plant roots.
Nutrient-Rich Worm Castings
Worm castings are the waste product excreted by earthworms, a process explained by the University of Arizona Cooperative Extension. The gizzard of an earthworm, which is similar to a chicken’s gizzard, grinds the soil and food the worms consume. As the material passes through the worm’s digestive tract, intestinal fluids are secreted, which contain enzymes such as sugars, amino acids and other organic matter. This nutrient mixture is then excreted in the form of castings, which bind to the soil and increase the soil’s fertility.
This process is a type of composting called vermicomposting, which differs from traditional composting. Instead of adding organic matter to a pile and waiting for it to decompose into usable compost that you add to your garden, adding worms directly to a vegetable garden bed allows you to provide nutrient-rich vermicompost to your plants on-site without having to turn and otherwise maintain a compost pile.
The University of Hawai’i at Manoa notes that vermicompost increases the yield of plants while also suppressing pests and diseases. The University additionally notes that vermicompost promotes more plant growth than traditionally produced compost. Unlike synthetic fertilizers that contain plant nutrients, which are not always available to plants, vermicompost produces plant-available nutrients, including nitrogen, phosphorus, potassium, calcium, magnesium and micronutrients.
Best Worms for Gardens
The Oklahoma Cooperative Extension Service ranks the best worm for gardens as Eisenia fetida, commonly called red wiggler worms or red tiger worms. Other worm species are also commonly called red wigglers, such as Lumbricus rubellus, which can be invasive pests. When purchasing red wiggler worms from bait shops or worm farms, make sure you release Eisenia fetida into your vegetable garden.
Red Wiggler Worms in Gardens
Although you can add red wiggler worms to any vegetable garden, adding worms to raised beds helps keep them contained. Red wigglers stay in the upper layer of topsoil and do not burrow deeply like other species, such as night crawlers (Lumbricus terrestris), which may dig down as deeply as 6 feet, according to North Carolina State Extension.
Because worms breathe through their skin, which needs to stay moist, keep them from drying out by adding a layer of mulch to keep the soil surface moist after releasing red wigglers in the vegetable garden. Straw, lawn clippings, crumbled brown leaves and shredded newspaper or paper bags serve as mulch as well as food for red wigglers.
With an indoor worm bin, you add vegetable peelings and other kitchen scraps, and adding this material to your vegetable garden may encourage wildlife to feed on the scraps. However, by instead choosing the aforementioned mulch materials and keeping the surface of the soil moist, red wigglers will have food to eat and water to keep them moist. [external_footer]