The usually beneficial earthworms can become pests in a garden or lawn because they attract predators like moles and birds that cause damage to turf and plants. Earthworms also eat roots of plants causing garden damage. Worm casts or the small digested piles of earth caused by earthworms make lawns slippery and make blades of lawn mowers blunt. Weeds grow on earthworm casts and affect the health and appearance of a lawn or garden. There are both natural and chemical earthworm control methods that keep earthworms from causing damage to the lawn or garden.
Herbicides have little effect on earthworms except for herbicides containing triazines. Triazines have mild toxic properties that irritate and repel earthworms.
Pellets of Tea Seed
Applying tea-seed pellets and watering the garden after application causes earthworms to come to the surface. Once earthworms come out from under the ground, gardeners can sweep or mow earthworms from the surface.
Watering the garden and lawn well every day will repel earthworms. Earthworms thrive in dry soil and excess water will make them come to surface for easy extermination.
Earthworms require soil with low acidity to thrive. Applying acid to alkaline soil will repel earthworms. Spraying calcinated sulphate of iron lowers the PH of soil and repels earthworms.
Mustard mixed with water and sprayed makes an effective vermifuge as earthworms dislike the pungency of mustard. Mustard is not harmful to the grass, other plants or human beings. Mustard therefore makes an environmentally friendly earthworm repellent.
Common chemical repellents used to exterminate earthworms include potassium permanganate and formalin. Spraying liquid detergent also brings earthworms to the surface for easy removal.
Some pesticides used to exterminate pests in a lawn or garden also effectively poison earthworms. Pesticides containing carbaryl or imidacloprid effectively get rid of earthworms.
Fungicides can irritate and exterminate earthworms. Fungicides containing thiophanate-methyl repel earthworms.
Ammonium-based fertilizers repel earthworms because they reduce the PH of soil beyond their preferred level.