Garden Slugs — UGG!!

Slug bait pan in a garden.

The recent rains have been a mixed blessing. For home gardeners, the wet conditions have brought a host of damaging pests out of dormancy; SLUGS!! These slimy creatures look like snails without a shell. They are gray, brown and other earth tone colors. This makes them difficult to see on the bare ground. They require moist conditions When it was dry, the burrow down in the ground and go dormant. The recent rains have brought them out of dormancy.

And their feeding damage is very evident. Hostas are a favorite food, but they will feed on any live or decaying plant material. They not only feed heavily on plant leaves, but will feed on root crops such as potatoes, carrots and beets. Although they don’t kill many of their victims with their feeding, they ruin food plants and make flower and foliage gardens extremely unsightly.

There are a number of control options available to reduce their numbers so they are less damaging. Drowning them in an attracting liquid is the easiest and is non-toxic to non-target species. This is done by sinking a shallow container in the ground so the top edge is at ground level. The old recommended bait was beer. This worked. But, it gets expensive. Slugs are attracted to the yeast in beer, not the alcohol. So substitute a mixture of water and baking yeast in the container. The slugs will crawl in to feed on the yeast and will drown. Place these drowning traps every 6 feet as this is about the distance they will sense the yeast. Empty the containers as they fill with dead slugs and replace the liquid yeast mix frequently.

Another effective control is any commercial product that contains Iron Phosphate. This is a bait that is usually sold as a small pellet. The pellets have yeast mixed in them when manufactured to attract the slugs. The iron phosphate is toxic to slugs and snails and kills quickly. An important advantage to using and iron phosphate bait that it is totally non-toxic to non-target animals. Birds, pets, children will not be affected at all by the bait. Slug predators can feed on the dead slugs with no ill effects.

This is vastly superior in safety to the baits which contained Metaldehyde. Metaldehyde will kill the slugs, but it is toxic to non-target species that eat the bait or the poisoned slugs. Birds and other predators can die from it as well as pets or people. For this reason it is not the recommended bait when other options are available.

Another control method is spraying with an ammonia and water solution. Household ammonia is mixed with water at a ratio of 1 part ammonia to 4 parts water. Plants and soil is lightly sprayed with the solution. Any that lands on a slug will kill it immediately. That which doesn’t land on a slug will be taken into the soil and be converted by bacteria to a form of nitrogen the plants can use. It is low cost and effective, but does require more labor. It is best done early in the morning or late evening when slugs are most active.

There are some other options for control such as coffee soil drench, copper wire around plants, and Diatomaceous earth. But all are less effective and/or more labor intensive to us.

Vegetable gardens should be rototilled late in the fall to dig up the hibernating slugs. By exposing them they may dry and die or not rebury themselves. Tilling the ground will also disturb and expose their eggs which will dry them and expose them to freezing as well.

One will never completely eliminate slugs in a yard and garden. But by using a combination of methods their damage can be reduced to negligible levels.