I doubt if there are many gardeners in western Oregon and Washington that have not had slugs or snails, or both, in their garden. In the early ’70s, I do not recall ever seeing snails. Slugs yes, but not snails. There are probably many reasons why we see them now, perhaps they were brought up on plants coming from California. Whatever the reason, we have them now, although in my garden slugs far outnumber snails. The control measures for both are similar.
Gardeners need to accept the fact that our mild and wet climate is an ideal environment for slugs and it is doubtful if a garden would ever be completely free of them. They feed on a wide variety of plants and often will go after succulent new growth early in the season. This can be particularly frustrating for gardeners, to see a dahlia sprout through the soil one day and to have it gone the next! Or to plant marigolds and have the leaves stripped overnight. Since slugs require moisture, there are some things we can do as a natural control such as removing pieces of wood or cardboard that slugs will often seek as a shady moist place to escape the sun.
Slugs do have some beneficial aspects because they recycle organic matter and return it to the soil and they are also food for wildlife, primarily birds. However, when their population is high, they can cause much damage to the plants in our garden. Since many of us are actively working in our gardens in the spring and early summer, that is when we probably see the most damage to our plants as the newly hatched slugs are hungry for tender green foliage.
Fall is an excellent time to gain some control on the slug population that will occur in the spring. Slugs lay eggs when the fall rains begin, late September and early October, and by preventing the adult from laying eggs we can reduce the population the following spring. There are many brands of slug baits and whichever one you chose, be sure to read and follow label instructions. Some baits can be used in vegetable gardens and some cannot. Some are relatively safe for people, pets, and wildlife and others are not. Before you make your purchase, be certain that you are getting the right product for your needs.
Slugs lay eggs in clusters and the eggs look like small pearls. They are usually buried in the ground in a moist location and if you cultivate in your garden, you have probably seen them. Often they can be mistaken for the popular fertilizer Osmocote.
When applying slug bait, if the soil is dry, water first so it is moist. Evening is a good time to apply baits because that is when the slugs will likely be most active. Sprinkle the bait lightly over the damp soil. Do NOT apply the bait in piles.
The active ingredient in most baits is metaldehyde, sodium ferric EDTA, or iron phosphate. Iron Phosphate is the ingredient in the well-known brand, Sluggo. This is an organic product that is relatively safe to wildlife and the environment. When a slug ingests iron phosphate it stops feeding and will often crawl to a damp place and thus may not be seen. Initially, gardeners thought Sluggo was not an effective bait because they did not see the dead slugs, whereas when slugs ingest other baits like Corry’s, Deadline, etc., the dead slugs will be very visible.
Regardless of your slug control method, now is an ideal time to apply. The spring population can be greatly reduced by applying now to kill the adult and prevent it from laying eggs. Once again, a reminder, be sure to read and follow label instructions.