Rather than planting whole rows of single vegetables, camouflage the plants by growing a mixture of different vegetables side by side. For instance, to protect collards from flea beetles, try interplanting with tomatoes or clover. Carrot flies will have trouble finding their dinner if carrots are companion-planted with onions. By growing broccoli and cucumbers in the same bed, gardeners can often avoid the ravages of cucumber beetles. Should the insects locate the plants despite interplanting, the next line of defense is incorporating herbs into the beds.
Herbs contain aromatic oils that are natural insect repellents.
Mints and rosemary repel many caterpillars, while catnip is a deterrent to flea beetles. Thyme, basil, dill and chives all give neighboring plants relief from caterpillars, flies, beetles and aphids. One of the best herb companions to plant is garlic.