Industrious earthworms perform several important jobs in your garden, says the U.S. Department of Agriculture, including:

  • Aerating soil. Tunneling worms make soil more porous and better able to hold water and oxygen, which are vital to plant health.
  • Facilitating root growth. Worm channels allow roots to penetrate deep layers of nutrient-rich soil more easily.
  • Fertilizing plants. Worm poo (castings) is rich in organic matter, a natural fertilizer for plants. And when worms die, their bodies decompose, adding more plant-loving nutrients to soil.

Healthy gardens have about 10 worms per spade of soil, says Jim Shaw of Uncle Jim’s Worm Farm in Spring Grove, Pa. Composting red worms stay close to the surface, while night crawlers that turn the soil live deeper down.

Healthy worms lay eggs every day or two. So if you want to grow more worms, you’ll have to keep the ones you have happy. That means keeping soil moist and digging in lots of rotting organics, like shredded leaves.

Buying worms

You can buy worms at worm farms; 500 red worms for composting cost about $25; 250 night crawlers will cost about $25.

When your worms arrive:

  • Place them in your compost pile to speed up the process. To keep your worms moist, water the pile and cover it with burlap or old carpet.
  • Dump worms in a heap in your garden, and they will naturally travel around enriching and conditioning soil as they wander. 

“Worms are a proven product,” says Shaw, who has sold them for the past 45 years. “They’ve been around since dirt.”