Trap Crops I Like to Use in My Garden for Pest Control

Trap crops attract insect pests and predatory insects to help keep their numbers down.

Vibrant orange Nasturtium flowers (Tropaeolum majus) in a vegetable plot
Vibrant orange Nasturtium flowers (Tropaeolum majus) in a vegetable plot. Jacky Parker Photography / Getty Images

Trap crops are an interesting solution for organic garden pest control. Along with other forms of companion planting, trap crops can be moderately effective for crop protection. Though I certainly would not say these alone are enough to protect your crops, they are certainly an integral part of an effective, holistic, and integrated pest management system. 

Trap crops are plants that are placed in the garden in a somewhat sacrificial capacity. They attract insect pests away from the primary crops you're trying to protect: The pests congregate on the trap crops in larger numbers rather than on other plants in your garden. Since the trap crops are riddled with pests, it then attracts predatory insects like ladybirds/ladybugs, lacewings, and parasitic wasps. These predatory insects take care of the pests and help maintain a natural balance in the ecosystem to keep pest numbers in check. 

A number of different plants can serve effectively as trap crops in a vegetable garden. Some do so more effectively than others. Here are some trap crops for garden pest control that I have found to be effective where I live:

Radishes

Radishes are one trap crop that I would highly recommend. They are simple to cultivate, grow very quickly, and can easily be placed between other slower-growing plants. Radishes can be good companion plants for a range of reasons. Some pests are actually deterred by their pungent scent, and quick-growing plants like radishes can be intercropped to make the most of space the time. But they are also very attractive to a range of insects and this is what makes them useful as a trap crop. 

I find they attract flea beetles and several pests which prey on brassicas. I often use radishes as a trap crop by placing some around slower-growing members of the cabbage family. And also place them close to zucchini and summer squash, or near lettuce, to keep flea beetles away. 

Nasturtiums

Nasturtiums are another extremely useful companion plant for a range of reasons. Though nasturtiums can run rampant if left to do so in some areas, they can often be a good choice for a vegetable garden. They are a crop in their own right, with a range of edible uses. But they grow so prolifically that they can also handle being used as a trap crop–often without actually sacrificing the plants. 

Nasturtiums, I find, are a great trap crop for several different pest species, including flea beetles, and also aphids, which can congregate on them in great numbers preferentially to other plants. This means they can be a good companion plant for Cucurbita and also for a range of other plants in a vegetable garden. 

Mustard

I use mustard primarily as green manure. But it can also be useful as a trap crop. I sometimes leave a few mustard plants in place as a trap crop for many common brassica pests, as a barrier between the main entrance to my polytunnel and main Brassica crops, sometimes even allowing one or two plants to self-seed, which they tend to do prolifically. But note these are at a remove from the main Brassicas (beyond some Alliums) since pests and disease can move between these related species. 

Sunflowers

sunflower

Greg Chapel / EyeEm / Getty Images

Sunflowers are another useful flowering companion plant for the vegetable garden. Sunflowers are another trap crop that is attractive to aphids and other sap-suckers. Ants can sometimes be seen herding aphids onto these plants. I sometimes grow sunflowers and amaranth along a border of a bed and find them an excellent companion plant alongside a polyculture of corn, beans, and squash (the three sisters). 

Though we do not have them here where I live, in the U.S., it is also notable that sunflowers can serve as an excellent trap crop for stink bugs. 

Stinging Nettles

Though not actually in the vegetable garden itself, I also allow plenty of stinging nettles to grow up nearby since it's an extremely useful plant even out of the context of pest control. As a trap crop, it attracts aphids and other insect pests and is a breeding ground for predatory insects—especially, I find, native ladybirds/ ladybugs. So these are also one of my favorite plants to keep down pest numbers on cultivated plants. 

The examples given above are just a few beneficial trap crops that I have found to be effective at least to a degree in my garden. Results may vary where you live. But experimenting with trap crops and other companion planting is certainly essential in holistic pest management in an organic garden.