Companion Planting at the Seed Bank

ECHO Asia intern, Jen Smeage, has spent the last several months evaluating companion planting at the seed bank.  According to the Wikipedia Companion planting entry (http://en.wikipedia.org/wiki/Companion_planting), this approach, whereby different crops are grown together, is intended to enable mixtures of select plants to assist each other in various ways, including with nutrient uptake, pest control and pollination.  Ultimately, this synergy is intended to increase crop production.  In addition to planting known compatible vegetables, various types of flowering plants are also planted to attract both beneficial insects, including pollinators such as bees and predators that eat pests such as aphids.  Some companion plants also serve as "trap crops," attracting pests away from vulnerable crops.  Some examples (University of Rhode Island; http://www.uri.edu/ce/factsheets/sheets/compplant.html) include:

• Basil planted among tomatoes may repel tomato hornworms.
• Marigolds, mint, thyme, or chamomile may repel cabbage moths.
• Radishes make excellent trap crops for cucumber beetles among squash and cucumbers. Radishes also attract flea beetles when planted near cole crops.

Companion crops being evaluated at the seed bank include cosmos, calendula, hyssop, allysum, peppermint and marigold.  Jen says that the companion crops are definitely attracting lots of pollinating bees at the seed bank as well as lady bugs and lacewings that eat pests such as aphids.  And she sees trap crops, such as allysum, attracting aphids.  However, the current cool-dry season doesn't have as much insect pressure as the upcoming hot and rainy seasons.  So the coming months will offer a critical time to evaluate the overall effectiveness of the companion crops on in pest management at the seed bank. 

For persons who delight in pure, orderly, organized stands of crops, companion planting be too messy for them.  But for those who appreciate the positive effects that crop biodiversity might bring, not to mention patches of color in a sea of green, then companion planting should definitely be considered and evaluated.