EARTHWORMS IN YOUR GARDEN
When you add nitrogen-rich compost to your soil, you help worms thrive. However, adding synthetic nitrogen fertilizers may repel earthworms. Worms are very sensitive to physical and chemical changes and will flee the salty conditions that result from an application of chemical fertilizer, so stick to organic fertilizers.
As an earthworm feeds, organic matter passes through its body and is excreted as granular dark castings. You may see these small casting piles in your garden. An earthworm produces its weight in castings daily. Worm castings are a wonderful fertilizer, rich in nutrients otherwise unavailable to plants, which is why you want to encourage earthworms to thrive in your garden.
In cold weather, a soil search will turn up mature and young earthworms as well as eggs. By late spring, most worms are mature. As temperatures rise, activity slows; many lay eggs and then die. By midsummer, most worms are very young or protected by egg capsules. As the weather cools, young worms emerge. With wet weather, they grow active, making new burrows and eating extra food, resulting in more worm castings. Egg laying occurs again. Activity will continue as long as soil stays damp.
After a heavy rain, earthworms often appear aboveground. They haven’t drowned. Fresh water doesn’t disturb earthworms—they need ongoing skin moisture to breathe—but stagnant or contaminated water forces them from their burrows. Earthworms can survive in soil that freezes gradually, but sudden freezing can kill them. Protect earthworms against sudden freezes with mulch or a cover crop, both of which also provide worms with food.
COMMERCIAL WORM BIN SYSTEMS
You can raise earthworms yourself using purchased redworms—a process called vermiculture or earthworm composting. Kept in a cool, dark place, such as a basement, a worm bin provides a composting system for kitchen scraps and a source of rich, fertile worm castings for the garden.
Commercially available bins are typically made from durable black plastic or other materials, with trays that fit on top of a base. The trays have mesh bottoms for drainage, and the base catches “worm tea” and dispenses it from a spigot so you can use it to water your plants. A top keeps light out and worms from escaping. You fill the lowest tray with a moist filler material, usually a soaked coir fiber brick or shredded paper, with a little compost or garden soil mixed in to provide beneficial organisms.