Snails are common garden pests that cause significant damage to tender plants. These mollusks feed using a rasping tongue called a radula, chewing irregular holes in leaves, flowers, and soft fruits like strawberries and tomatoes. Snails are especially fond of young seedlings and new, succulent growth, which they can completely devour overnight. Their presence is often revealed by the silvery, slimy trail they leave behind. Effective management requires a multi-pronged approach that makes the environment unappealing to them.
Modifying the Habitat and Environment
Controlling a snail population starts by disrupting the cool, moist conditions they require to thrive. Snails are primarily nocturnal and seek damp, dark shelter during the day to avoid dehydration and bright sunlight. Altering your garden’s environment makes the area far less hospitable for these pests.
Adjusting your watering schedule is a simple yet effective control method. Snails are most active at night, and watering in the evening leaves the soil surface moist, creating an ideal highway for them to travel and feed. Shifting watering to the morning allows the soil’s surface to dry before dusk, reducing the moisture snails need to move comfortably. Switching to drip irrigation further reduces surface moisture and overall humidity, which snails find attractive.
Removing daytime hiding spots eliminates the shelter snails rely on to survive the day. Debris such as old boards, stones, low-hanging leaves, and dense weeds provide excellent retreats. Removing these havens forces the mollusks to seek shelter elsewhere, making them more vulnerable to predators or desiccation. Heavy layers of mulch can also harbor snails, so pulling it away from the base of vulnerable plants is a helpful preventative step.
Creating Physical Barriers
Physical barriers offer a non-toxic method for protecting vulnerable plants by creating surfaces snails are unable or unwilling to cross. These exclusion methods are effective when applied around high-value plants or raised garden beds.
Copper is a highly regarded deterrent, often used as tape or wire wrapped around pots or garden edges. When a snail contacts the copper, a reaction occurs between the metal and the mucus it secretes. This reaction causes a mild neurological disruption, prompting the mollusk to retreat. For the barrier to be effective, copper tape should be applied in a strip at least two inches wide to prevent snails from bridging the gap.
Diatomaceous Earth (DE) is a fine powder made from the fossilized remains of tiny aquatic organisms. It works mechanically, as the microscopic, sharp edges of the particles abrade the snail’s soft outer layer. This action causes the snail to lose moisture rapidly, leading to dehydration. A continuous band of DE creates an abrasive barrier, but it must be reapplied after rain or heavy watering, as moisture renders the powder ineffective.
Other rough materials can also be used as physical deterrents that snails dislike crossing. Crushed eggshells, sharp sand, or gravel form a jagged surface difficult for their soft bodies to traverse. These materials create a protective ring that snails are reluctant to slide over. They are best used around individual plants or as a top layer of soil, provided they are kept dry to maintain their rough texture.
Utilizing Baits and Targeted Removal
Active methods of population reduction involve using baits to eliminate existing snails or manually removing them from the garden. Commercial baits are available, but understanding the active ingredients is important for safety reasons.
The two main types of molluscicides are metaldehyde and iron phosphate. Metaldehyde is highly effective but poses significant risks, as it is toxic to pets, wildlife, and children if ingested. Iron phosphate-based baits are a safer alternative, working by disrupting the snail’s digestive system. However, some iron phosphate products contain EDTA to increase effectiveness, which may still be harmful to earthworms or toxic if consumed in large quantities by dogs.
Simple, non-chemical traps can also be used to lure and capture snails. Beer traps utilize a shallow container, buried flush with the soil surface. Snails are attracted to the yeast and fermenting odor, crawl in, and drown. A mixture of water, sugar, and baker’s yeast can be substituted for beer with similar results.
Targeted removal is a practical method, especially for smaller gardens. Snails can be easily collected by hand during their active hours, typically after sunset or early in the morning. Placing overturned melon rinds, citrus peels, or flat boards on the ground creates a dark, moist trap where snails congregate during the day. The collected pests can then be disposed of in a bucket of soapy water.