A well-mulched acidic garden will almost always attract snails. They are usually first noticeable in the vegetable garden in the early spring. The snails start feeding on the plants at the bottom, and work their way up. By the time damage to the plants is evident, the vegetable garden may already be intensely infested. Snails can be kept out of the vegetable garden with monitoring and vigilance. Check under flower pots and garden stones regularly for snails to be alerted to their arrival in the garden. Catching the problem early will prevent snail populations from building up.
Pluck the snails out of the vegetable garden by hand early in the morning before the dew has evaporated, or in the evening, as the snail typically feeds at night. Use gloves to avoid the touching the slimy bodies. Place the snails in a bucket of soapy water to carry them away for disposal.
Leave the skins of grapefruit in the vegetable garden to attract the snails. When placed upside down, the snails will gather under the skins and can be easily gathered up.
Dig out a shallow area in the garden, just wide and deep enough to hold a pie plate so that the lip is just below the surface. Fill the pie plate with beer. As the beer stales, it will attract snails and they will drown in the pie plate, making it easy to collect them. Change out the beer every three or four days.
Sprinkle a ridge of wood ashes around the plants, about 3 inches wide and an inch high, as a snail barrier. Keep the ash barrier from touching the vegetable plant. The ash barrier works best under dry conditions.
Place thick boards near snail infested areas of the vegetable garden. Snails tend to gather in sheltered areas during sunlit daylight hours. Once a day, lift the boards and remove and dispose of the snails.
Encourage toads, robins and starlings and even garter snakes into the environment to protect the vegetables in the garden from snails. They are all natural predators.
Deprive snails of a place to winter in the garden by removing rocks, boards and garden debris from the vegetable garden.
Crush eggshells and spread them around the valuable vegetable plants. The sharp edges of the eggshell barrier will cut the soft body of the snail if it tries to cross.