I just got from worm's way

Volume 5, Issue 8 - August 2006 •
Organic Gardening
Hydroponics Propagation Pest Control

Why Can't We All Just Get Along?
Companion Planting for IPM

Just like people, plants can be selective of the company they keep. Some prefer the solitude of their own space while other pairings form symbiotic relationships and coexist like two peas in a pod.

Described as close proximity cultivation of two or more plant types in order to achieve a cultural benefit, companion planting has been practiced for centuries. It is used for flavor and growth enhancement, vertical support and protective sheltering, although companion planting is most frequently implemented by gardeners to support their earth-friendly Integrated Pest Management (IPM) efforts. Here's a look at three distinct methods of plantings for pest control.

The first approach involves choosing plants that can repel scent-driven pests or mask the aroma that attracts host-specific insects. Strong-smelling herbs like basil, catnip, dill, thyme, coriander, oregano, and most mint species serve this purpose well and can be intermittently planted within garden rows. If you have some of these specimens established elsewhere, you can also cut and occasionally scatter the leaves around the plants you're trying to protect and achieve similar results. Just as effective, but better reserved as border plantings, are wormwood, tansy and pennyroyal. Some garden vegetables and ornamentals that produce similar results include garlic, onion, chives and scented geraniums.
Positive hosting is another way to incorporate companion planting as a pest control measure. Rather than discouraging insects however, this method aims to attract beneficial populations like lady bugs and green lacewings. Once established, they will feed on damaging undesirables such as aphids, thrips, spider mites and white flies. Multiple-bloom, composite flowers like yarrow, marigold, sunflower, chrysanthemum and daisies provide great nectar-filled food sources for benenficials. Queen Anne's lace and dandelions do the same and give you a good reason to let these weeds be.

The third option, known as trap cropping, requires a bit more planning and maintenance. In this instance, specimens are selected and planted specifically to attract pests away from what would otherwise be their preferred host. Pest identification, growth and feeding habits along with trap-plant selection and location are all important variables to consider as the trap crop must be more appealing to the pest in order to be effective. These crops are monitored regularly and, once insects take the bait, the trap crop can be treated with an insecticide or carefully removed and disposed of. Blue Hubbard squash, for example, has been recognized as a suitable companion planted as a perimeter around summer squash and cucumber to draw in the striped cucumber beetle.

Whether you choose to execute one or all of these techniques, keep in mind that results won't occur overnight. And because there are so many potential insectary pairings, who knows? Maybe you'll be the one to discover the next great match!