This column, the first of a series on managing herbivores in the chemical-free garden, is part of a larger series of columns devoted to helping new gardeners. This seems a fitting task for the winter months, allowing the novice gardener time to gather ideas and materials.
In June 2009, a reader in Wesley responded by mail to a recent column on slugs in the garden. She had tried all of my suggestions for controlling slugs with minimal results, but had her own method that really worked.
“I take an empty can, put a little salt in the bottom and, using a plastic teaspoon, go around and pick them up, the first thing in the morning. When I get done, I sprinkle some more salt on them and they are out of commission. They exude a liquid when they hit the salt.” In this manner she salted down 5,651 slugs in 2008.
A Tenants Harbor reader, recently transplanted from Alaska where slugs are numerous and large, emailed her recommendation for slug control, a mixture of half water and half household ammonia. “We keep the mixture in a spray bottle ready to zap the critters whenever they appear” she emailed. “On contact, the slugs will sizzle and dissolve.”
Also by email came good advice from a Town Hill gardener: “I turned my chickens loose last fall and I feel that I have a lot fewer slugs to contend with. Guinea hens will keep your garden slug and bug free without the damage to plants that accompanies chickens.”
Marjorie came up with a way to keep her ripening strawberries out of the reach of slugs. Patrolling the four rows, she props each ripening berry off the ground with a recycled plastic fork, cradling the fruiting stem in the tines. We pick ripe strawberries free of slug bites, but the berries are in full view of every crow and jay perched on a garden fence post.
So go the slug wars. Weapons in the arsenal are numerous and varied, but the gardener wins skirmishes at best. The slugs keep sending reinforcements.
Most Maine gardeners are battling the gray garden slug, a destructive three-quarter-inch slimy villain varying in color from yellow to black with brown specks and mottling. They appear in hordes during wet, cool summers, mowing seedlings to the ground and climbing up stems to suck the juice from ripe tomatoes, all in the dark of night. During the day, they hide from the sun in the crevices of stones, under boards, or beneath the garden mulch.
In their hiding places, they — meaning just about all of them, since slugs are hermaphroditic, each with both male and female reproductive organs — lay eggs. And not just a few; each adult, over a life span of 9 to 13 months, will lay between 300 and 500 eggs, clusters of clear, jellylike eggs about an eighth of an inch in diameter.
Slug eggs are very resistant to cold and drying and are often the only life stage to overwinter in the garden. At cold temperatures, 32 to 45 degrees Fahrenheit, it may take 100 days for eggs to hatch. But in late May, it only takes 10 days. Newly hatched slugs resemble their parent, only much smaller.
Slugs are very fond of just-emerging vegetable seedlings. In one night the tiny seedlings that you waited two weeks to see emerging from the soil can be rasped to the ground, leaving only the ragged bases of stems.
Garden slugs take us to the brink of chemical warfare, yet we persist in fighting the battle with only nonchemical weapons. Unless you consider beer a chemical weapon. Beer traps, shallow containers set at ground level and covered loosely with a board, do work. We scatter traps wherever slugs feed and find several sunken slugs each morning.
Or save the beer and just dig a small hole in the garden bed, cover it with a board or piece of bark, and the next morning you likely will find slugs resting in the hole. Time to get out the empty can, spoon and salt! Truthfully, I just fish them out of the hole and toss them far into the woods, hoping to make a toad happy.
Slugs will avoid crawling over anything scratchy, including wood ashes, course sawdust, gravel and sand. I encircle every planting with wood ashes and I apply ashes into the crevices between stones around the garden beds. These treatments have to be repeated after two or three heavy rains, and I always run out of ashes before running out of slugs. And slugs will find even the narrowest gap left in the ring of ashes.
Sowings can be protected from slugs with a fence made from fly screen cut into 4-inch strips and placed on edge, partly embedded in the soil for support. The fence can be removed once the seedlings reach the five-leaf stage and stems toughen.
If you like to wander about the garden before sunrise, try baiting slugs with citrus fruits. Squeeze the juice from several oranges or grapefruits and scatter the halves around the garden before dark, leaving one inside edge close to the ground for easy access. Stroll through the garden before dawn, picking up the “traps” and disposing of the slugs by feeding them to your chickens and guinea hens.
Some gardeners swear by the copper tape sold to deter slugs from potted plants and raised beds. The tape has adhesive on one side to secure it to the pot rim or bed edges. Slugs trying to cross the copper get a small electric shock.
Finally, don’t make it easy for the slugs to find daytime shelter in your garden. Remove logs, boards, and rocks from the garden and keep surrounding plants cut low to the ground.
Send queries to Gardening Questions, P.O. Box 418, Ellsworth 04605, or to firstname.lastname@example.org. Include name, address and telephone number.