Managing Slugs in Your Garden
Tis the moist, humid season for slugs! If your garden is anything like mine, you’re probably dealing with lots of slug damage right now! Slug damage is easily identifiable by large, rounded holes in leaves (compared to caterpillars, which often, but not always, leave scalloped edges), and by their characteristic shiny slime trails.
Slugs are particularly active this time of year, when your garden is wet with rains!
To properly manage slugs in your garden without using harmful chemicals, you’ll need to apply a combination of best practices.
First, remove all slug habitat near your garden, so slugs have fewer protected places to wait out conditions that are too hot, cold, or dry for them. Slugs love damp, dark places they can get underneath — decks, large rocks, garden pots, boxes or other items stored outdoors, etc. Large plants with low-hanging leaves also make good slug habitat. If appropriate for the plant, you can pull these leaves off to help reduce slug homes in your garden. Unfortunately for me, my garden is built from moss rock stones; so I’ll never fully remove all slug habitat. However, I do notice that the garden bed with the most significant slug damage is the one closest to my potted container garden. May be coincidence, but to the extent that you can remove slug habitat near your garden, you will be helping yourself out!
Second, you can intentionally set slug traps that you empty out every morning. Examples of habitats listed above make great traps! Consider placing a board, brick, rock, or pot in your garden that you use to intentionally draw slugs — just remember to come out every morning to remove the slugs from the garden! If you prefer, you can construct wooden traps using a piece of plywood (12x15” should do the trick) raised off the ground by 1” runners, which make it possible for the slugs to crawl underneath. Scrape off the accumulated snails and slugs daily and destroy them; either by crushing them, feeding them to your ducks or chickens, putting them in a bucket with soapy water and disposing of them in your compost pile after they are dead, or placing them in the trash. Another option for killing slugs you have collected is to spray them with a solution of household ammonia diluted to a 5 to 10% solution in water. I don’t recommend using salt to destroy snails and slugs, since it can increase soil salinity if not done properly.
Some people recommend beer-baited traps to catch and drown slugs, who are attracted to the fermented bait. The Transform Your Yard crew performed an experiment with beer-baited traps in my garden, with limited success. First, the traps need to be buried at ground level to catch slugs, and deep enough that slugs cannot crawl out. They only attract slugs within a few feet of their placement, so if you go this route you’ll need numerous traps. Also, because of evaporation, you’ll need to refill the bait on a regular basis. In the end, we found this method fun but relatively ineffective.
If your garden is contained within a limited number of raised beds, you can consider using copper foil to create a copper barrier (at least 4” wide) between slugs and your veggies. It is believed that copper barriers are effective because the copper reacts with the slime that snails and slugs secrete, causing a disruption in their nervous system similar to an electric shock. You can also create a copper barrier directly in the soil, burying a portion of it to prevent slugs from crawling beneath the barrier. This method can be expensive if your garden is large, but works great for contained gardens in raised beds!
A common permaculture solution for slugs and snails are ducks and geese! Preferred to chickens (who will eat your seedlings too!), ducks and geese are acclaimed effective slug patrol for your garden. While I have no experience with this personally, stay tuned to upcoming posts — this year I’ll be raising ducklings for just this purpose!
Beyond these strategies, your most effective slug deterrent will be manual slug control! Slugs are active at night, so once every other night head out to your garden with a headlamp, and you’ll see them everywhere! Gather them up by the handful, and dispose of them as you wish (some suggestions above). After a week or so of doing this every night, you should be able to reduce your evening slug collections to once per week.
A note: I would not recommend using snail and slug bait products, with the exception of Slugg-O. Metaldehyde baits (the most common ones) are poisonous to cats and dogs, so avoid these products! Slugg-O is an iron phosphate bait — safe for use around children and domesticated and wild animals. To use, scatter the Slugg-O around your vegetables repeatedly, replenishing as the bait is consumed. Slugg-O is more effective on snails than slugs, but combined with the other strategies above can be part of your integrated pest management plan for slugs in your garden!
