For four years, I’ve written Not Wanted columns in a neutral, objective style. This one is different.
Most gardeners actively love their soil. We celebrate the creatures that help make it fertile. Earthworms are visible partners; whenever I see them a little cheer goes up inside.
This spring I bought several yards of combined compost and yard soil, a dark, moist, fecund mixture, from a reputable local source. For months I joyfully put it to use: double-digging it into the tomato trench; transplanting young shrubs and trees—redbuds, tulip trees and dawn redwoods I grew from seed; building and expanding beds for shrubs, flowers and vegetables; and transplanting thousands of native perennial wildflowers, grown from seed from Prairie Moon Nursery, a great resource for native plants.
Suddenly, there were worms, everywhere. And they were different. Big, vigorous, muscular, with snakelike movements when disturbed. A pale band an inch or two from the head. An iridescent sheen as they wriggled. Just below the leaf mulch surface, in the top couple inches of the soil. And the soil was different. In large areas it had morphed, almost overnight, into a blanket of uniform, crumbly, coffee-ground-like worm castings.
I looked up jumping worms and immediately realized it was a massive infestation. The more I learned, the more my heart sank.
What I learned.
Jumping worms live in the top couple inches of soil, going deeper only briefly to hide. They completely transform those couple of inches. With astonishing speed, they devour much of the organic layer of leaves or mulch and replace it with a homogenous mass of castings—worm poop. Castings are a great organic fertilizer…underground, where plant roots can use them, not on the surface.
Jumping worms eliminate seed banks and the Mycorrhizal (fungal) network that connects plants underground. They leave voids in the soil that destabilize soils, dry out plant roots, increase erosion and leach nutrients.
They only live a year, dying after hard frosts. But in the fall they produce scores of durable poppy seed-size cocoons that overwinter and hatch in the spring. They reproduce so rapidly—50 to 100 per worm per year—that a few worms one year could be an infestation the next.
Jumping worms travel only a few dozen feet a year. But humans move them around further and faster as we transfer cocoon-laden plants, soil and mulch. From their origins in Asia, their numbers have exploded in Connecticut, especially in the last couple of years, partly due to increased demand during the pandemic and our extreme moisture.
There is as yet no chemical or biological cure. A ton of research is being conducted on this new threat and promising strategies are being tested. What we do right now to kill adults before they reproduce is critical. Here’s what I’m doing, based on expert advice, especially from the CT Agricultural Experiment Station. Lots more resources, photos and more are available at granbyinvasiveplants.weebly.com
What to do
1. Search and Destroy. I look for areas where the mulch or leaf layer is thin or replaced by exposed castings. With my hand or a tool I disturb the soil; if jumping worms are present, they are obvious, wriggling vigorously. I grab them (not by the tail because it can break off) and drop in a bucket of water with added dish detergent, which kills them in less than an hour. It doesn’t take long to kill hundreds. It makes me feel better to count; each dead worm is 100 fewer next year. I wear rubber gloves to cut the gross factor. If I wear Crocs, they come to me, passing through the holes and crawling over my toes.
2. Stop the Spread. For potted plants, I take them out of the pot and shake off the dirt into a large container, grabbing any worms that show and dumping into the soapy water. I wash all the soil off the roots in a succession of buckets, each cleaner than the last, to ensure no worms or cocoons. Then I repot using purified soil, or plant in the ground. Spread the wash water on a hot road on a sunny day.
3. Purify the soil. I evenly spread suspect soil, and soil removed from potted plants, on a plastic sheet in the sunny driveway, no more than 6” deep, leaving a border of at least a foot all around, extracting and chucking into the soapy water the worms that show themselves as I shovel. I spread a second sheet of clear plastic on top, with a similar border, roll the borders together and tape it closed all around. Temperatures over 105 degrees for several days—longer as the season progresses —kill the worms and cocoons, yielding purified usable soil. Without the bottom layer and the sealed edges, worms avoid the heat by burrowing into cooler soil. I’ll cook smaller batches in the oven indoors.
4. Confess, Explain, Support. At first, I was so distressed at our infestation that I didn’t want to tell anyone, like it’s a deep, shameful family secret. Then I realized they are everywhere, and everyone needs to know what they can do, right now.
We can all stop the spread.
Look around your property:
• If you find them, focus on them as soon as you can, before they reproduce.
• If you are buying soil or mulch: make sure the seller has heated the material to over 105 degrees for several days with no way for the worms to escape.
• If you are buying or exchanging plants: choose bare-root only, or use the laborious method above to wash all the dirt off and purify it.
• If you fish: don’t buy worms for bait unless you absolutely know they are not jumping worms.
Take care of yourself.
Gardeners, tree planters, farmers, anyone who puts stuff in the ground and helps it get bigger, better, more beautiful, more productive—we all worship at the altar of hope. Whether we think about it a lot, or not at all, we hope if we put seeds or plants together with the essentials—light, water, nutrients—things will grow. Soil is the key, and Granby has glorious soil, the sandy loam holds moisture but drains, is nutrient-rich, without a lot of rocks or clay.
Jumping worms made me feel hopeless. They cut through my heart. I felt disgusted, at war with nature. I began to fantasize about pavement, moving to an apartment. These feelings are common, I learned; there are resources to help (“Emotional Support for People with Jumping Worms,” U. of Minnesota Extension). For me, taking action is a salve, I recommend it.