I’m no longer able to find an earthworm in my garden, whereas before, they were innumerable. What happened to them? Is there a method for how to increase earthworm population in soil?
Where Did My Earthworms Go?
Earthworms do hibernate, burrowing as much as 6 feet down to escape frozen soil, but if you’re digging in your garden, I’m going to assume it’s not frozen.
Many things can lead to earthworm decline, including ecological degradation, over-tillage, and overuse of chemical fertilizers. But this isn’t the case for most organic gardeners who practice no-till methods.
How often do you add compost? Earthworms are valuable for gardens specifically because they consume this organic material, and their digestive process frees up nutrients so they’re bioavailable to plants. Earthworms also turn the soil and help compost degrade faster so plants can use it sooner. Since you’re not doing anything to actively kill the earthworms, they may have left to find food somewhere else.
How to Increase Earthworm Population in Soil
Several practices, some of which you’re already doing, can protect earthworms and other subterranean life:
Don’t Till Your Garden More Than Necessary
Rototillers are great for breaking up hard clay and chopping organic material for new beds. But once those beds are established, tiller blades can chop through worms and bring mycorrhizal fungi to the surface, where they die. It can also eliminate air pockets, which keep the soil loose, facilitate decomposition, and allow worms to breathe.
Add Mulch to Garden Soil
Exposed soil is dying soil. As the sun dehydrates soil, microbes die. Hot, dry soil can’t sustain earthworms either. Lawns, though they don’t have food value for humans, do provide a thick layer of soil protection — and those earthworms come out at night or when it rains. Keep your garden soil covered by applying organic material around crops. In winter, apply straw or leaf litter, which will decompose while protecting subterranean life.
What to Feed Worms
What to feed worms can be as simple as leaving roots in the ground after crops die. If you need a clean appearance for a homeowners association, cut crops at soil level so roots remain intact, then chop the upper part to apply as compost. Layer on material from compost piles so the worms can come to the surface and grab a bite. Then, in spring, dig some of that material into the earth so it can decompose at root level.
If you continue to add a substantial compost layer and then practice no-till and mulching methods, your worms should be back soon.
Can I Revive My Potatoes?
I’m using a cold frame, or “hot box,” for the first time. My soil temperature is great for potatoes, around 58 degrees Fahrenheit. But the air in the box got too hot, and now all the leaves and stalks are brown and slumped. Can they recover, or do I need to wait until next year for a successful potato harvest?
Potatoes are one of the hardiest garden crops I’ve ever grown. Though their tops are heat-sensitive and frost-sensitive, the roots can handle a lot of abuse. They’re also quick to spring back after damage, as long as the damage isn’t systemic (such as blight).
For assurance, dig down until you find a potato near the surface; if it’s solid, not wrinkled or mushy, your potatoes are just fine. Because your soil temperature is great, keep those potatoes in the ground and vent the hot box, since you most likely still have a great root structure. The potatoes will send up more tops and start over. This will delay your time to harvest, but it’ll be quicker than starting all over.
This concept is similar to how gardeners plant potatoes in mid-March, even though their last frost dates are in late May. Frost might bite back the tops, but the roots will still be going strong.
Marissa Ames is the former editorial director for Ogden Publications and manager of MOTHER EARTH NEWS, Grit, Countryside, Goat Journal, Backyard Beekeeping, and Backyard Poultry magazines. She and her husband, Russ, travel to Africa where they serve as agricultural advisors for the nonprofit I Am Zambia. She spends her free time eating lunch.
Originally published as “Where Did My Earthworms Go?” and “Can I Revive My Potatoes?” in the Ask our Experts column of the October/November 2023 issue of MOTHER EARTH NEWS magazine and regularly vetted for accuracy.
