One of the reasons I enjoy speaking engagements on gardening is because people come up with some great questions.

Last weekend before one of the talks, a lady asked me about companion planting. Her son wanted to plant onions and tomatoes together, and she wondered if the onions would hinder the tomato growth.

I told her they would be absolutely fine together.

What is Companion Planting?

Companion planting isn’t a new concept, and the nifty thing is it does work. One of the most valuable nuggets of importance with companion planting is that monoculture is bad. When there’s a whole lot of one thing in an area, its an open invitation for problems.

Companion planting, on the other hand, confuses pests, sometimes by repelling them with a noxious (to an insect) scent or by simply masking the crops. You’re also providing places for the beneficial bugs to hang out. This way they can be right there ready to pounce on those nasty aphids or hornworms.

The onions, as the lady asked about, can discourage slugs and ants; it is useful around lettuce, tomatoes, beets and strawberries. Radishes are good around peas and lettuce to discourage pests in general. And plant brassicas near strong smelling herbs such as pennyroyal, chamomile, rosemary or dill to help keep the cabbage moths from finding them.

Companion Planting with Herbs

Herbs and aromatic flowers are important parts of companion planting. Most people are familiar with using marigolds in the garden to deter deer and other pests. They are useful to some degree, although Ill be the first to tell you that a whole barrier of marigolds wont stop hungry deer from hitting your squash or anything else they want.

Rue is not a very common herb, but its strong smell does a good job keeping Japanese beetles away from your favorite flowers. I recommend you wear gloves and long sleeves when working with it, though, because it can cause a nasty rash. (I speak from experience.)

One thing I really want to try is planting catnip to keep away the flea beetles. I haven’t had a problem at home, but many of my friends struggled with them in other places so they’re all going to receive catnip starts this spring. Oh, and I cant forget calendula, which deters hornworms on tomatoes. (Plus, it’s mighty tasty in muffins, and is invaluable when it comes to skin care.)

How to Arrange Plants

Now this is the hard part for gardeners: if youre not planting in neat little rows, how do you plant this stuff?

It’s time to step out of the traditional planting methods and mix it up a bit. Trust me, its not going to stop the world from spinning on its axis if you have a couple of flowers or herbs in the middle of the strawberries or snuggled up next to a tomato plant. If it did, we would’ve ground to a halt a long time ago.

If you have issues with cabbage moths, plant those herbs close to the cabbage, broccoli, or similar. While I’m on the subject, you might want to put those in the same family in different places in the garden. If you have them spread out you are less likely to lose the whole thing to pests that might come calling.

There are books filled with information on companion planting. Start by planting a few herbs or flowers to discourage pests, and don’t hesitate to make unusual vegetables close neighbors. It’s not going to be a miracle fix, but if you keep along this path you’ll notice a difference in the pest levels.