With plant swaps and compost exchanges in full swing, it’s important to keep an eye out for invasive jumping worms. These critters will leach nutrients out of the soil so quickly they can kill local plants, unlike regular earthworms that are considered beneficial for the soil. Luckily, there’s a simple trick to help keep these pests at bay.
How to spot a jumping worm
Jumping worms move like hyped-up earthworms. They thrash around, and slither like snakes, unlike native earthworms that tend to move much more slowly. They also have a light-colored band closer to their head than native earthworms. If you see any jumping worms in soil you have purchased or in plants from a store or a swap, you need to perform mitigation procedures before the soil goes into the ground.
When transporting soil from one place to another, it’s important to look for jumping worms—if you’re not sure if the soil is contaminated, you should “solarize” it before it goes into the garden. Some garden soil from stores will already have been treated, but it’s often the case with free compost or soil giveaways that it may not have been, so you should always check.
How to solarize your soil
Before placing new soil in your garden beds, you should “solarize” it. This involves spreading the soil out on some black plastic at a depth of no more than six inches, covering the soil over with plastic, and leaving it in the sun for an afternoon. When you spread the soil out, you should look for jumping worms. Even if you don’t see any, the cocoons could still be alive. The key is to heat up the soil to at least 105°F using heat from the sun. If you buy soil or compost in bags, you can place them in a black plastic trash bag in the sun for an afternoon for the same effect. You can use a soil thermometer to make sure the soil gets warm enough.
Once the soil is already in the ground, solarization won’t work because the worms are free to move to cooler areas of the soil once it’s exposed to heat. You can warm up the top six inches or so, but underneath, the soil will remain at a relatively constant temperature. Once the transported soil is in the ground, it’s notoriously hard to get rid of invasive worms, so treating it before it gets mixed into the rest of the dirt is important.
The spread-and-pick method
There is also the spread-and-pick method to remove worms—and it’s exactly what it sounds like. Just spread the soil out on a tarp or some plastic and look for jumping worms. When you see them, pick them out and put them in a plastic trash bag and discard it in the garbage, not the compost bin. Birds might lend you a hand with the spread and pick method, but they’re less discerning about what kind of worms they eat. Also, the spread-and-pick method can allow some cocoons to persist. That’s why the best way to tackle the problem is to use heat.
To prevent the spread of jumping worms in places like plant swaps, you can try trading bare rooted starts without potting soil. Bare root plants can be placed in sterile potting soil for transportation, and this method should stop the worms from hitching a ride.
