In this article, we will explore the kinder, gentler (or at least relatively non-toxic) methods of slug and snail control.
The simplest method of controlling slugs and snails is keeping up with your weeding. If slugs and snails can’t find weeds to eat, they may not hang around for seedlings to germinate or bulbs to sprout. Pulling weeds that come up before your flowers or vegetables will increase the chances that your garden bed will remain slug- and snail-free.
Use a variety of different flowers and vegetables in every planting bed. Slugs and snails may find just one kind of plant tastier, and leave the others alone. This also makes it easier for you to locate the pests.
Adopt a turtle. Turtles require some maintenance and will feed on tender greens if you let them, but they are helpful for controlling snails and slugs at the edges of your property. Or if your property is large enough, incorporate ducks or peacocks into your garden plan. Muscovy ducks, which originated in the tropics, are more suitable for controlling giant African snails.
Don’t get in a hurry to kill snakes. Garter snakes, which are non-poisonous, eat slugs.
An organic method of slug control is feeding your plants fertilizers that contain iron (ferric) phosphate, which is available in pellet form. This form of iron ensures your plants grow dark green leaves, preventing the plant disease chlorosis, and also reduces the appetite of snails and slugs. It doesn’t kill the pests outright, but it greatly reduces their appetite. The iron residues in your garden are non-toxic to people, pets, and beneficial insects in your garden, although it is important never to take the product internally.
Another organic approach to snail and slug control is providing them with a coffee break or tea time. Caffeine from very strong black tea or from black coffee, or from commercial caffeine sprays gives these pestiferous critters the jitters. As the animal absorbs caffeine, it loses its ability to extend its foot. This makes it impossible for the slug or snail to move forward. At higher concentrations, caffeine causes the muscles to go into tetany so that the snail or slug is frozen in place. You can put gloves on your hands and remove it for disposal in the trash.
Of course, you can always just go out into your garden and pick snails and slugs by hand. The drawback to this approach is that it is best done at night, when slugs are active. You have to carry a flashlight to find the slugs. Repeated visits to the garden, every night for one to two weeks, are usually needed to make a serious dent in your slug or snail infestation.
Slug and Snail Traps
Another way of disposing of slugs and snails is creating a “hotel” with the empty rinds of melons, grapefruit, oranges, or lemons. Rather than throwing out the rind, cut out a tiny “door” and place the rind or peel upside down over damp soil. Slugs and snails will congregate during the day, and you collect them (again, with gloves on your hands so you don’t catch parasites or get your fingers slimy) for disposal in a sealed plastic bag you place in the trash. If you want to trap and release, take them at least 100 meters (330 feet) away from your garden so they do not find their way back.
It’s also possible to ply these pests into captivity with alcoholic beverages. Slugs are fond of yeasty beers like Budweiser and Michelob, although they also enjoy a good dark stout. Bury shallow container like half a beer can, a pie tin, or a tuna fish can in the soil and cover the bottom with beer. Slugs will come up to drink and not be able to get out. You only need to collect the drunken slugs once a day for disposal. If you can’t or don’t want to obtain beer, you can also use brewer’s yeast dissolved in a little sugar water.
Nematodes are microscopic worm-like parasites that can kill slugs, snails, and problem insects. You can buy nematode eggs in garden supply centers. Simply mix the nematode eggs in water and spray as directed. The slugs, snails, or insect pests die from nematode infections.
Pellets for Slug and Snail Control
Gardeners are familiar with the little blue pellets called Meta. Formulated to contain about 5% metaldehyde and 95% cereal, the pellets are designed to be tasty to slugs but invisible to birds and small mammals. It’s best to sprinkle the pellets among the plants you want to protect. Mounding them increases the odor of the metaldehyde and may actually drive slugs away.
Metaldehyde metabolizes to acetaldehyde, the same chemical that causes humans to experience hangovers when they get drunk. At low concentrations, metaldehyde interferes with a slug’s ability to move purposefully. At higher concentrations, it causes massive secretion of mucus and fatal dehydration.
What Methods of Slug and Snail Control Are Likely to Backfire?
Broad-spectrum pesticides kill the insects (such as glowworms and other beetles) that keep slugs in control.
Ground-level electric fences can cause stunting and malformation in your garden plants, even if they don’t touch your plants. If you place an electrified wire low enough to zap a slug or snail, it will probably also eventually give you a shock on your ankle or heel, and it presents a hazard for your pets.
And it can be a very bad idea to get your revenge on snails by cooking them up as escargot or to take out your frustrations with garden slugs by looking in Chinese cookbooks for sea slug recipes. Laboratory studies have found that excessive consumption of snail meat interferes with the formation of bones. Both slugs and snails pick up parasites from animal dung. If they have fed on dung in your garden, they can pass on parasites from the dung to you. Both slugs and snails accumulate heavy metals, especially if you provide them with well-limed, slightly alkaline soil. Black slugs bioaccumulate mercury. Field slugs accumulate blood thinners used in rat poison. And the poisons you use to control moles, voles, rats, mice, squirrels, gophers, groundhogs, or other garden pests accumulate in the bodies of snails and slugs, especially the larger snails that grow in tropical climates.