How to Stop Worms in the Garden

Earthworms can cause unsightly casts in lawns.

Worms, particularly nightcrawlers, can cause some aesthetic damage to lawns and landscaping. Worm casts are the unappealing mounds of dirt that collect on the ground as a result of worm activity. Yet, worms can improve soil drainage and nutrient conditions. The only guaranteed way to stop worms from living in your garden is to make the environment too harsh for them to survive, such as by increasing soil acidity. Unfortunately, this often has the unintended side effect of damaging grass and plants in the garden. Instead, consider reducing worm populations through a couple of alternative techniques.

Things You'll Need

• Bucket
• Dish-washing liquid
• Carbaryl (Sevin)
• Water
• Gloves

Instructions

1. Aim a generous squirt of dish-washing liquid into a bucket. Use a brand marked as environmentally friendly, or similar. This should cause little residual damage to your soil and lawn. Alternatively, try 2 oz. off table mustard, suggests the University of Central Lancashire's Earthworm Research Group.

2. Fill the bucket with warm water. Take the bucket to the location where you're having worm troubles. Look for evidence of worm casts, such as curled mounds of sticky mud on the surface of the soil.

3. Pour the soapy water onto the ground, covering a few square feet at a time. Wait 30 minutes and check the ground. Worms in that area will come to the surface to escape the soapy conditions. Pick up the worms and place in the trash or another bucket.

4. Try the insecticide carbaryl, often sold under the trade name Sevin. Two or three carbaryl applications can reduce nightcrawler numbers by 50 percent, according to Ron Smith, a horticulturist at the University of North Dakota.

5. Mix the carbaryl with water in doses according to pack instructions for general worm or lawn insect removal. Pour the mix over worm-infested areas.

6. Repeat applications of carbaryl or washing liquid if you notice worm casings return in the next few weeks.

Tips & Warnings

• Use the worms you catch as great live fishing bait.

• Apply carbaryl or warm dish-washing liquid to soil in the early morning or in the evening. During the day worms often dig deeper, away from the hot and dry topsoil.

• Wear gloves when handling carbaryl.

References

• North Dakota State University Hortiscope: Questions On Nightcrawlers
• University of Central Lancashire: How to Sample for Earthworms