How do I prevent pests without chemicals?
Written by
Nguyen Minh
Reviewed by
Prof. Samuel Fitzgerald, Ph.D.Pest control, organic and chemical free, is part of square foot gardening, using an ecosystem of plants rather than chemicals. Marigolds alone have removed aphids from client gardens. Marigolds' roots emit alpha-terthienyl, which inhibits nematodes. Through a clever pairing of plants and timing, mini self-replicating habitats can be created.
Companion Planting
- Marigolds repel tomato hornworms within 3-foot radius
- Basil masks cucumber beetle attractants in squash
- Nasturtiums trap aphids away from brassicas
Biological Controls
- Release lacewings at dusk (500 eggs/100 sq ft)
- Install owl boxes for rodent control
- Brew compost tea with nematode-killing fungi
Physical Barriers
- Floating row covers with 0.6mm mesh block cabbage moths
- Copper tape repels slugs within 24 hours
- Yellow sticky traps reduce whitefly populations by 70%
Timing is critical for success. Neem oil should be applied at 7 a.m. when the plant "pores" open, and it will increase absorption into the leaf by up to 40%. My preferred recipe is 1 tbsp neem and 1/2 tsp Castile soap per gallon; both products kill pests on contact. For persistent squash bugs, I recommend handpicking adults daily, including at dawn when they are less active.
Bring in a predator with habitat layers. My client has 18 types of ladybugs in his yard from adding yarrow and dill. A pile of rocks 12" deep is a home for ground beetles that eat 50 cutworms nightly. Lastly, diversity is the best policy for pests.
Read the full article: Ultimate Square Foot Gardening Guide: Maximize Your Harvest
