Companion planting is the concept that certain plants benefit each other through pest control when theyre growing next to each other because the chemical components in each of the plants discourage pests on another. I cant say the full reasons of why it works, but a lot of people swear by it.

I must admit that I haven’t done much with companion planting, mostly because I’m more concerned with crop rotation and trying to cram as many plants as possible into the garden.

Three Sisters Garden Method

I did plant the Three Sisters garden last year. Its an age old Navaho planting method combining corn, beans and squash. The corn is planted first in a circle on top of a mound roughly the size of a trash can lid. After the corn is roughly six inches high, plant the pole beans at the base. This way the beans grow up the corn stalks helping to support them, as well as fixing nitrogen into the soil.

Squash is planted in between the corn/bean mounds to grow and cover the area. This shades the ground and keeps down weeds in between the corn. It worked great.

Control Pests with Companion Planting

Companion planting can be even more involved when it comes to pest control. For example, aromatic plants are well known to discourage unwanted insects. Try strong smelling herbs like southernwood or hyssop near cabbage and other brassicas to ward off the cabbage butterfly.

On the flip side, it’s equally important to understand what plants dont grow well together. Leeks and cabbage actually shouldnt be planted close to each other because theyre both heavy feeders. But they do well with carrots, and help keep the carrot flies away due to their strong smell.

Popular Companion Plantings

It’s hard to sum up companion planting in anything less than a book-length narrative, but here are a few of the more popular pairings:

• Carrots with tomatoes (Just like the well-known book, Carrots Love Tomatoes), lettuce, leeks and onions
• Corn with peas, beans, squash or cucumbers
• Radishes with cucumbers or lettuce
• Potatoes with beans, radishes or horseradish
• Onions with beets and radishes
• Beans with corn, carrots, cabbage, eggplant and Swiss chard
• Beets with kohlrabi, carrots and onions
• Onions with carrots, leeks, kohlrabi, lettuce, peppers and tomatoes
• Radishes with bush beans, carrots, cucumbers, lettuce and melons
• Tomatoes with basil, asparagus (some people plant them along the edge of the asparagus patch), beans, onions and cucumbers

Garlic is great with cucumbers, lettuce, celery and peas, as well as being an effective repellent against aphids on roses.

Use the fragrant French or Mexican marigolds (some of the hybrids dont have much for fragrance) throughout the garden to discourages a lot of insects and nematodes. However, they often do attract spider mites.

If you’re not sure about how companion planting is going to work, choose a couple of combinations for a season. It may not make your garden pest free, but it certainly wont hurt to give it a try.