Gardeners aren’t the only ones overjoyed by the year’s first flush of growth. Rodents, deer and a whole host of creepy crawly things are just as eager to feast upon the plants those gardeners work so hard to nurture.
Organic methods of pest control are becoming increasingly popular among health- and environment-conscious growers. From erecting fences and spraying solutions to strategically planting protective crops and dispatching armies of “good” bugs into the air and soil, there’s a whole host of strategies to help ensure those veggies make it to the table.
Fencing, and other repellents
In spring, rodents and small mammals are looking to fill their bellies.
“You’ve got these nice succulent 2- to 3-inch plants, and a rabbit says, ‘Looks good to me,’” said Tim Wolfe, owner of Lake Street Garden Center in Salem.
The best way to keep them from feeding on your work is by building a fence, but that doesn’t sit well with many gardeners, Wolfe said.
“Aesthetically, they don’t like the way it looks,” he said. “Some people take a lot of pride on how the garden looks. They don’t want a big ugly fence; they want nice rows of vegetables they can see from their kitchen window.”
Instead, gardeners can sprinkle their plants with popular organic repellents like Propolis, which uses ingredients like garlic oil and egg solids and smells horrible enough to get animals running for the woods — sometimes. The hungriest of specimens won’t let a little stank keep them out.
For those who can put aside compositional woes, fences provide superior protection. Wolfe suggests a 4-footer constructed out of metal chicken wire strung between posts. The key is leaving the mesh fairly loose between the posts.
“It’s more difficult for a woodchuck to climb up,” Wolfe said. “They’re pretty good climbers. But they are kind of fat, so it makes it difficult when the mesh kind of wobbles.”
That’ll do for the smaller animals, but deer are another story — they just might get in no matter what you do. Some gardeners try tricks like stringing up bars of Irish Spring soap, which supposedly smells like humans and makes deer want to go away. Paula Kovecses, founder of T.W.I.G. Horticultural consulting, is a certified organic land care professional. She suggests spending a few extra bucks to buy cheap green shrubs to plant in the woods. Because they are farther from people, deer will go for them before they venture to a garden.
Another sneaky option: some people construct an invisible fence using fishing line. The deer don’t see it and it scares them. As a last resort, try electric fencing, but even that could fall short. If they really want to eat your plants, deer will just jump over it.
“To really keep out deer you almost have to have a 7½- or 8-foot fence,” Wolfe said.
Insects killing insects
All kinds of insects love a garden, and each plant has its own worst enemy. Squash Vine borers wage war on squash. Potato beetles pick on (you guessed it) potatoes. Tomatoes and parsley have their own kinds of worms. Traditionally, seasoned organic farmers who know when each bug will arrive have intervened with sprays designed to deal with a particular pest.
“You have to know a little bit more about what you’re dealing with before you can treat it,” Wolfe said.
But more and more gardeners are releasing armies of insects that act as board swords, combating all of these enemies at once and making pest control easier for the beginning grower.
Beneficial nematodes seem to be the most successful. These soft round worms come in a carton the size of a yogurt container that has enough to cover 200 square feet of soil. Gardeners sprinkle a third of them at a time for three days. The worms burrow into the soil and “hunt a whole laundry list of typical vegetable garden insects,” Wolfe said.
If nematodes seem too good to be true, there is one small hitch that scientists are getting close to solving — the worms work best when they kill insects before they surface, which means getting to them early in the season. But nematodes also don’t do too well in cold weather.
“The big challenge now is making ones that handle cold weather so they can live over the winter and won’t have to be re-applied,” Wolfe said. “[Scientists] are working on that and hoping to eventually have one.”
What are some other beneficial bugs? Some gardeners purchase ladybugs and praying mantises, but there’s some controversy around how well they work — some think they’ll wander off. But if there is something there for to them to eat, they will generally stick around, Wolfe said.
Perhaps the most bizarre beneficial bug is the Chalcid wasp. It’s a tiny predatory insect that lays its eggs in the “bad bugs,” and when the eggs hatch, the host insect bursts.
“That’s something we introduce into the greenhouse,” Wolfe said. “It’s not something you always get outside naturally.”
Protecting plants with native plants
Before you run to the store and purchase a container of nematodes or a swarm of ladybugs, Kovecses says staking out the kinds of natural defenses already on your property will do wonders for your green-thumbed endeavors. Keeping a balanced ecosystem in the garden right from the beginning is absolutely crucial, and it’s one of the most healthy defenses against the dark arts of predators.
Back in the 1990s, if growers had any sort of problem they sprayed a chemical. But that takes nature out of balance, Kovecses said, because those chemicals are one-stop killers, fending off the bad bugs but also the good.
The key to a healthy garden it maintaining as many native plants as possible. Scope out your own land first to identify the plants and trees that grow naturally, and do a little research about what kind of helpful bugs they attract.
There are hundreds of useful plants: Yarrow, a hearty and versatile perennial, has fernlike leaves and colorful flowers. It attracts ladybugs and lacewings, small native flying bugs that gobble up troublesome aphids. Beebalm plants, whose colorful flowers bloom early to mid summer, also attract lacewing, and bees too. The green herb dill is another good option.
Kovecses says having just one plant each of a couple different species is a good start, but the more the merrier, so if you don’t have them already, they can be planted along the edges of vegetable gardens or alongside fruit- and veggie-bearing varieties.
As seen in the April 17, 2014 issue of the Hippo.