Since I moved to upstate South Carolina two years ago, something has been eating my seedlings. One day I have lettuce, carrot, basil, or broccoli seedlings just barely showing up through the soil, the next day they are all gone. Not a trace. Damping off and cutworms would leave the fallen seedling. I think animals even the size of rabbits would leave prints or scat. I want to blame grasshoppers (there are certainly plenty around), but in 2 years I’ve never actually seen the culprit. I’ve made little 2″x2″ window-screen houses and that seems to keep whatever-it-is from ruining my crops. Still, it’s a pain. Any idea what the root cause might be? Thanks!
Upstate SC Gardener
I would love to see your tiny window screen houses! Even though they sound adorably elfin, I bet having to build all those 2” x 2” mini-houses begins to dampen your gardening enthusiasm after a while.
The mystery villain is probably slugs! These slippery creatures typically make their visitations during the night, do the damage, and disappear in the light of day; leaving you to wonder where on earth your seedlings went.
You can test for slugs by laying a wide board flat on damp ground near your plants overnight. The next morning, check underneath the board to see if slugs are present. If they are, drop them into a jar of soapy water or sprinkle them with salt (sounds cruel doesn’t it?). Slugs are active at night and love damp conditions. To substantially reduce slug damage, avoid watering in the evening ~ but in a wet year, you may have to take more drastic measures.
Warning! Regular snail bait often contains Metaldehyde. It is frequently flavored with molasses and it attracts slugs, but it also attracts pets who think it resembles food. Very small amounts of metaldehyde can be toxic, and even fatal, to pets. Liquid and powdered metaldehyde baits can get on paws and then be licked off, poisoning animals. Additionally, metaldehyde baits are ineffective after getting wet.
There are slug & snail baits that are safe for pets and wildlife, and suitable for organic gardeners. They are effective; some people say they are even more effective than metaldehyde. The active ingredient in these pet-friendly products is iron phosphate, and some brands are OMRI approved. Typical brand names are SLUGGO® and Escar-Go! They will not loose their effectivness after rains, they continue working for up to two weeks, and the bait that is left uneaten by slugs will biodegrade. Slugs stop feeding after eating the bait, they become less mobile, and they begin dieing within three to six days. Dead slugs/snails are not usually visible in the treated area, as they crawl off to die in secluded spots.
Prior to application of Sluggo® type baits, wet the ground if it is dry, and scatter the bait evenly on the soil around or near the plants to be protected, and around the perimeter of the garden. Do not leave in piles. Scatter the bait at a rate of 1 lb. per 1000 square feet, or 1 teaspoon per square yard, and more heavily for severe infestations. Evening is the best time to apply, since slugs mostly feed at night. Reapply as the bait is eaten, after extremely heavy rains, or at least every two weeks. Sluggo works on just about everything, including landscaped areas, gardens, orchards, and container pots.
More slug solutions for organic gardeners:
- You can significantly reduce your slug damage by watering in the morning, so your soil is dry by evening ~ since slugs enjoy damp conditions and work at night.
- Lay out a wide board, half a down-turned citrus fruit, or a flowerpot wedged up to allow access. This creates the sort of moist oasis that slugs love. Each morning, destroy collected slugs by dropping them in soapy water. If picking slugs up with your fingers makes you squeamish, use a trowel, a spoon, tongs, or even chopsticks.
- Be sure to pull the mulch back from your plant stems to protect them from slug damage. Mulch makes a perfect, dark, moist daytime habitat for slugs. Larger plants are less susceptible than seedlings.
- Encourage natural predators such as ground beetles, frogs, and birds by providing habitat. Ground beetles will live under the wide boards you have laid out to trap slugs. Frogs love damp conditions and enjoy eating slugs. Birds require vegetative cover and water.
- In The New Organic Grower, Elliot Coleman recommends ducks for slug control, but remember that ducks and chickens may also eat your seedlings. You can let your domesticated birds forage on newly turned ground, which should help eliminate slug eggs and diminish subsequent population numbers. According to Permaculturist Bill Mollison, “You don’t have a slug excess, you’ve got a duck deficit!”
- Make or purchase a beer trap. Slugs are attracted to beer, so bury a container (like a cottage cheese container) in the ground, with the rim about 1” above soil level. This will capture the slugs and drown them, but keep ground beetles (their natural predator) from falling in. Empty the trap regularly, and top off with more beer – flat beer is fine. Research shows that slugs like grape juice too; cheap juice is fine.
- Copper deters slugs by causing them to experience an electrical-type shock. The area must be completely encircled in copper, and the copper must be wide enough, or tall enough, that the slugs are forced to touch it.
- One Internet source swore that mullein leaves (fresh or dried) “repelled slugs like the plague” when applied around plants like a mulch.
- Salt kills slugs, but an addition of lots of salt to your soil is not a good thing. One source suggested sprinkling Epson Salt around your plants.
- Abrasive materials like eggshells, builders sand (it’s sharp), coffee grounds, or diatomaceous earth can be sprinkled around the plants as a physical deterrent that slugs find disagreeable. Diatomaceous earth works best when the weather is dry, so reapply after a rain. Microscopically, DE is very sharp and acts to shred slug
tissues. *Utilize the safety precautions on the label when applying diatomaceous earth. Abrasive materials were the least-favored option in my research.
Here’s to slug freedom!
Ask Ruth © 2013 Ruth Gonzalez & Organic Growers School
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Ruth Gonzalez is a former market farmer, gardener, and local food advocate who wants to see organic farms proliferate and organic gardens in every yard. She serves on the Organic Growers School Board of Directors, and in her job at Reems Creek Nursery, Ruth offers advice on all sorts of gardening questions, and benefits daily from the wisdom of local gardeners.