Organic Gardening Basics: Organic Pest and Weed Control

Enlarge Image Image Gallery Planting seedlings makes identifying weeds easy—they’re whatever you didn’t plant!

Anyone can grow plants. There’s lots of information out there, more than you could possibly ever read, more than you would want to, and many of the sources contradict each other. Don’t worry! Start however you can, find mentors, and let your experience with the plants be your guide. If you stick with it, each year will bring you greater abundance.

Pest Patrol 

Every vegetable garden hosts a wide range of insects, the majority of which are harmless or beneficial. Plant diversity helps naturally “balance” insect life in a garden, so plant easy-to-grow herbs and summer flowers­—try Greek oregano, catnip, sweet alyssum and calendula—alongside produce. Tall sunflowers serve as perches for bug-eating birds.

Spend the first year in your garden learning about insect life. The more you know about your insect foes, the better you can defend your crops. You’ll know pest species from beneficial bugs because they will gather in scary numbers on specific plants. Check plants twice a week for unusual insect activity. When you notice insects damaging a crop, capture a few in a jar and study them until you can make a positive identification (see “What’s Buggin’ You?” below). Pick troublemakers off by hand and drop them into soapy water (none of the common garden pests bite or sting). Most infestations can be controlled with simple methods such as hand picking and encouraging beneficial insects. And don’t forget our feathered friends—birds and poultry feast on all kinds of garden pests.

Bug Battle 

For insect battles you can’t win with hand-to-hand combat, you may need to call in reinforcements. Fortunately, an organic control product exists for nearly every type of pest.

1. Fire ants, leaf-eating caterpillars and beetles: Try biological pesticides based on naturally occurring soil bacteria. The oldest, Bt (Bacillus thuringiensis ssp. kurstaki), works well on caterpillars. Spinosad is useful for fire ants and beetles. If pests require repeated treatment, alternate the two to keep insects from becoming resistant.

2. Aphids, leafhoppers, snails and slugs: Diatomaceous earth is a natural material that kills pests by dehydration. The effects are short-lived because it seeps into soil after rain, but a thorough, well-timed dusting can work wonders. You can also make leaves less tempting by painting them with a paste of kaolin clay and water. Organic produce that has traces of a dusty, off-white residue was probably treated with kaolin clay.

3. Aphids, mites and other small sucking insects: Control these bugs with two applications of insecticidal soap (available at garden stores) five to seven days apart. Blast infested plants with a strong spray of water to dislodge offenders, then apply soap to kill any left. (Once insects are washed to the ground, few make it back up to growing tips.) Use soap sparingly: It can reduce yields of some crops and damage leaves if applied on a hot, sunny day.