How to cultivate a healthy, pest-resistant garden
During my first few years of growing perennial foods I rarely thought about bugs because I hardly saw any. I find this astonishing given how much of my time is now spent beating them back. Maybe the newness of my farm helped protect it? I don’t know but by my fourth summer on the farm the bugs had arrived. Lots of them.
There were leaf miners tunneling through the tender leaves of chard, aphids sucking the living sap out of my red currant bushes, flea beetles chewing tiny pin holes in my broccoli and, worst of all, the cabbage moth.
Cabbage moths lay hundreds of eggs that hatch into large velvety green caterpillars, which greedily eat chunks of leaves. Left on their own they can decimate a garden. The trick is to catch the soft yellow and white winged adults before they have a chance to lay eggs. This is not an easy task since their wobbly flight patterns make them nearly impossible to catch. I’ve tried sticky traps. I've chased them with butterfly nets. I've shot them down with a high-powered hose.
So desperate was I to save my tender crops from these ravenous moths that one day I dug around in the back of the greenhouse and grabbed an old tennis racket. Bolting onto the field, I swung furiously at every moth unfortunate enough to cross my path. Yelling and swinging the racket, I finally stunned a moth. My dog Nimbus ran up behind me and pounced on it, pinning it with her paw so she could rip off the wings. Success!
Needless to say this is not an efficient way to tackle your moth problem, though it’s not a bad way to release all your frustration with them.
So I hit the books, studying up on organic and sustainable ways to keep pests at bay, and here’s what I learned: It's important to cultivate a diverse, native-to-your-region garden. Doing so will support healthy growth, and the healthier your plants, the less likely they’ll send out the distress signals that invite trouble, because pests tend to feed on the most vulnerable plants.
How to cultivate a healthy garden
Invite good bugs to do your work for you. You might not realize it but there is such a thing as a good bug. Honey bees and wasps pollinate crops, lacewings devour aphids, and ground beetles prey on slugs. Spiders are also a gardener’s friend. The world’s spider population, estimated to weigh nearly 25 million tons, eats up to 800 million tons of insects each year!
Put out the welcome mat by planting many different types of plants that bloom and ripen at different times. Growing a diversity of plants creates a hospitable habitat full of food, like pollen, all year long. Shady plants give them a way to escape from afternoon sun so they continue to do the hard work for you. Without food and shelter that lasts from one season to the next, the good bugs leave and your garden suffers.
Plant natives. Native plants have adapted to local soil and climate conditions. This makes them more likely to thrive and less likely to be attacked by pests. It also means they’re better able to fend off native pests. In the event of an infestation, the plants will use natural defenses to protect themselves.
Hand pluck bugs. Picking bugs off your plants may not be the most desirable way to manage pests but it can be pretty effective. One trick is knowing where they like to hang out. Check for bugs under leaves, near the tips of stems, or in dense foliage, where many like to hide out from the sun. Once you’ve spotted your pest, remove it from the plant and place it in a lidded bucket or jar you carry around with you. Some gardeners I know fill the jars with water so bugs are less likely to climb out or even drown.
I search for slugs, another common pest, at dusk when the sun is low and the dew is gathering on my plants. My garden borders a horse sanctuary and the fields they graze are prime territory for a slimy migration into my yard. Five-gallon bucket of saltwater in hand, I walk this border, tossing in every slug I see. The saltwater kills them. Another option is spray slugs with a solution made of equal parts vinegar to water, or one part household ammonia to four parts water.
Use bug traps. Don't simply run after your bugs. Work on making them come to you. To take care of flying insects, I set out sticky traps, which you can find in any gardening supply store. To rid your garden of slugs and snails, lay down pieces of plywood on tall grass during the heat of the day and wait for them to gather underneath. They don’t like being in the sun, which can make them shrivel and die. Just lift the the board after a few hours and toss the bugs.
Another way to trap slugs is with beer. Take a deep container, like the kind used for yogurt, and half bury it close to any plants your slugs happen to love. Fill it halfway with beer. The scent of the beer will lure in the slugs and the beer will drown them.
Drape your plant in fabric. The most effective way to keep bugs off your plants is by covering them with row covers, or lightweight pieces of fabric. Lay the fabric directly over your plants, or construct a frame to support it. I like to use tomato cages as a frame when I’m wrapping smaller plants, like herbs and vegetables. This also allows air to circulate between the fabric and plants, reducing the risk of mildew.
The downside is that wrapped plants look a bit ghostly and can distract from your garden’s natural beauty. You also have to remember to remove row covers periodically to allow bugs to pollinate your crop or else you’ll end up without any fruit or vegetables. Harvesting is pretty easy, however. Just pull back the cover when it’s time to reap what you’ve sowed.
Note: I keep extra fabric on hand to repair any damaged or torn row covers. You can cut small pieces for patching large sections with small holes or tears. Sew on your patches by using waxed dental floss because it's cheap and surprisingly strong. In a pinch, you can just tape the fabric together.
Bring in a few birds. Chickens and ducks happily seek out pests, like wood bugs and slugs, and gobble them up. If you’re not up for the work involved in maintaining a flock of domestic birds, you can invite wild ones by putting up nesting boxes and planting trees for them to sit in and take cover under. I sprinkle seeds and dried flowers around the garden year round, instead of composting them, to give birds a reason to stick around.
Acadia Tucker is a farmer in New Hampshire. Her book, Growing Perennial Foods: A field guide to raising resilient herbs, fruits, and vegetables, is available for sale in our bookstore, along with her second book, Growing Good Food: A citizen's guide to backyard carbon farming.
This is part of our series on radical gardening, or how to grow food to help the planet. To find out more about growing your own perennials, check out our Perennial Profiles.