Pest Control for the Vegetable Garden

by Karen Gross

One of the biggest challenges for vegetable gardeners is pest control. Anyone who has tried to keep a determined deer from eating the sweet corn knows how difficult it can be to deter animals,  including insects, birds, rabbits and other wildlife from what, for them is a natural smorgasbord. From their perspective, there sit these wonderful veggies, all neat and weeded, almost as if you placed the plants there just for them. And so animals that we might otherwise enjoy can become a nuisance when it comes to the garden.

While avoiding wildlife is nearly impossible, chemical pesticides are often an effective means of deterring unwanted insects. However, many gardeners are uncomfortable using these harsh chemicals that can leak into water supplies and harm the environment. They also have concerns about using chemicals in the foods they feed their families. Here are some ideas for more organic pest control.

Crop Rotation

Practicing crop rotation every year in your vegetable garden and using companion plants will improve your soil and keep the pests under control. Most insects need time to become established in the soil. They may take two to three seasons to get their life cycle established. By practicing vegetable rotation and varying the type of plants grown in a particular area from year to year, you can avoid establishing plant specific types of garden pests.

Companion Planting

Certain varieties of garden plants are less attractive to pests. To deter rabbits, plant green onions amongst the lettuce plants. Plant several radish seeds in each hill of cucumber seeds to protect against the cucumber beetle. And when planted near each other, cucumbers will prevent raccoons from eating all the sweet corn, while the corn will reciprocate by preventing cucumber wilt.

Tomatoes like to be near chives, parsley, marigolds, garlic bulbs, nasturtiums, gooseberries, asparagus, and carrots. Tomatoes have a natural defense for pest control against the asparagus beetle and are also effective in keeping insects away from gooseberries. Carrots on the other hand are nearly every garden pest’s friend. To control the carrot fly pest, plant onions, rosemary, or leeks nearby. Potatoes like to be planted near corn, horseradish, broccoli, cabbage and peas. Avoid planting by tomatoes, melon, and cucumbers.

Some vegetable gardeners plant pumpkins, squash, and cucumbers among the corn. The heavy growth and scratching of the vines and leaves helps keep rabbits, raccoons and other hungry critters at bay.

Tricks of the Trade

In addition to the planting methods described above, there are a number of non-pesticide options for organic pest control. Human or dog hair spread around the garden and hung from tree limbs acts as a good pest repellent, as do bars of soap hung from shepherds hooks or laid right in the soil. Deer do not like the smell of rotting eggs, so a mixture of 9 eggs with 2.5 gallons of water sprayed on ½ acre of crop will deter deer from entering the area, but the solution is diluted enough to avoid annoying humans.

Deer tend to be nervous and wary animals and can be scared off by annoying wind activated garden fixtures, plastic foil tape, scarecrows and whirligigs. Those that make noise, such squeaking, fluttering, or tinkling, work best. You may have to move these items around and rotate selection to keep the deer from getting use to them. Dogs are also a good source to keep watch over the garden and help scare off unwanted wildlife diners.

Tall fences (9 to 10 feet high) planted firmly in the ground are the best way to keep deer out of the vegetable garden. An inexpensive chicken-wire fence at least 24 inches high is often enough to keep those pesky rabbits out of your garden. Or a solution of cayenne pepper spray on the plants after a rain will sometimes deter rabbits from nibbling. Dried blood meal, which rabbits do not favor, can be sprinkled around when planting. The flavor will absorb though the root system of the vegetables, making them less appetizing. As an ongoing garden pest control, blood meal can be added to the soil every two weeks.

Live traps can be used for smaller rodents and rabbits. Bait the traps with a small amount of peanut butter, check them regularly, and transport any captured animals to another location immediately. Wear plastic gloves when handling live traps to prevent exposure to diseases carried by rodents and their parasites. Sticky insect traps and lures are another good pest control. Paint a thick piece of cardboard a bright color to attract the pest, and coat with a sticky substance such as Stick-em or Tanglefoot.

Electronic Pest Control

There are several electronic pest control devices available on the market as well, including electric fences, motion detecting water sprayers, and ultrasonic noisemakers that humans can’t hear, but that garden pests find annoying. There are some units on the market that allow you to adjust the unit to the pest you are trying to drive away, without bothering the other critters you would like to have around.

Electric fencing can be installed around the perimeter of the yard. Some of these products claim to be strong enough to deter deer from entering the garden, but weak enough that they do not hurt family pets.

Moles feed on earthworms and grubs, not plants, which can make them a benefit to gardens, but as part of their natural activity, moles tunnel through the soil, causing damage to delicate plant roots. Battery or solar operated devices can be placed in the ground to help deter moles from burrowing in your garden. Place a few around the garden to prevent these pests from making paths in a new area.

Beneficial Bugs

Insects that prey upon garden pests are called beneficial insects. In nature these insects keep the garden pests under control. Encourage beneficial bugs by avoiding the use of commercial pesticides as these are usually non-discriminatory and will kill good and bad bugs alike. A small number of pests in the garden will encourage those beneficial bugs to stick around and multiply, making your work easier.

Ladybugs are natural enemies of aphids. Green lacewing in larvae stage feeds on thrips, mites, aphids, and various other insect eggs. Trichogramma wasps are effective against corn earworm, tomato hornworm, and loopers. The tiny wasps are also a parasite to many kinds of caterpillars.

Sprays and Soaps

There are many organic pest control sprays you can make at home, as well as purchasing less harmful insecticidal soaps. Many of the homemade sprays include ingredients such as garlic, onion, or cayenne pepper. A word of caution when using sprays intended to go directly on the plants. Never apply sprays in the heat of the afternoon sun. The water can heat up very quickly and cause brown spots to appear on the leaves.

Most gardeners have a connection with the earth and enjoy the wildlife and insects nature has provided…just not in the garden! For those who prefer to practice organic pest control, there are many options. They may not work as well as pesticides in some cases, but they are a lot less harmful and can even add fun and beauty to your garden.

About the Author

Karen Gross is a professional gardener and design consultant. She provides valuable tips and advice about seed companies, container gardening and other vegetable gardening topics.