Slugs are one of the most hated of garden pests. You may have spent time carefully planting out your seedlings into the bed, but when you return next morning, you find chewed leaves, the growing points nibbled away and a mass of slimy trails all around. All clear evidence that garden slugs, or sometimes snails, have been enjoying a nocturnal feast at your expense.
Slugs thrive in moist temperate conditions and feed at night when temperatures are greater than 50°F. They love mild winters, wet springs, moist summers, and irrigation. When you look at ways of protecting your plants, the large number of defences and remedies that have been suggested indicates the extent of the problem.
Since slugs need somewhere to hide during the day, the first line of defense is to keep your garden tidy and remove any flat stones, boards, pots or piles of damp plant refuse. Once you have achieved this, here is a list of other methods that you can try:
Barriers. Slugs dislike rough surfaces so sprinkle crushed eggshells, sharp grit, lime or Diatomaceous Earth around the stems of your plants. Copper strips are also an effective barrier since contact produces an electrical charge which slugs dislike. Copper wire shaped into a tight conical spiral with the narrow end buried in the soil is an alternative. In each case make sure that there are no slugs inside the barrier when you put it in place.
Collect by hand and destroy by sprinkling with salt or dunking in a bucket of soapy water. This is best done after dark.
Trap by placing small pieces of board or flat stones near your plants. Each morning check the traps and dispose of all slugs that you find.
Beer trap. Sink a small bowl into the bed and fill with a mixture of beer and water. Slugs are attracted by the smell and will fall in and drown. Some people have found non-alcholic beer to be more effective. Keep the bowl covered to prevent other creatures taking the bait. There is a commercial version called Slug-X which can just be placed on the surface of the soil.
Treats. Place grapefruit peel or old lettuce leaves near the plants you are trying to protect in the hopes that the slugs will be distracted. Another suggestion is to plant marigolds in the bed since slugs love these and so will ignore your favored plants. However others claim that slugs seem to avoid plants with strong-smelling foliage, such as marigolds.
Iron Phosphate granules. These granules have a wheat aroma to attract slugs. After eating them, slugs stop feeding, dry out, and die within a few days. This is a non-toxic product which is available commercially as Sluggo.
Chemical treatments include ammonia. Dilute with an equal quantity of water and spray on soil and leaves - test each plant first by spraying on a small section and leaving for a couple of days. The other chemical is metaldehyde which is sold as slug pellets. This is not recommended since it is harmful to birds and pets.
Encourage your local wildlife to do the job for you. Birds, frogs and toads will all eat slugs. So feed the birds and welcome frogs into your garden pond.
Water your plants in the morning so that the foliage will not stay damp overnight.
If all else fails, change your plants. In general, slugs dislike anything with leaves that are glossy, waxy or hairy so that there is quite a long list of slug-resistant plants that you can choose as an alternative. As with many aspects of gardening, you will often find that choosing plants that are suited to the soil conditions in your garden will produce the best results. If this means growing flowers that that tend to be ignored by slugs, you will have a far easier time than if you have to wage a constant battle to protect plants that are being continually attacked.
Hugh Harris-Evans is the owner of The Garden Supplies Advisor where you will find further articles, gardening tips and product reviews.