How to Keep Cabbage Worms Out of Your Garden—and Save Your Favorite Vegetables

Cabbage worms don’t just eat cabbage—they also dine on broccoli, kale, cauliflower, and other cold-season crops. Worse, they can be very tricky to spot. These bright green caterpillars often blend in with the surrounding foliage, so you may not even notice them until they've already damaged your garden.

Fortunately, there are a few good ways to prevent cabbage worms from destroying your plants. Follow these tips from a gardening pro and a pest control expert to get rid of them once and for all.

Try Inspection and Hand Picking

At least twice a week, inspect the underside of the leaves for cabbage moth eggs, which appear as tiny yellow or white dots—or for green caterpillars. “Crush or remove them by hand,” says Mihael Velev, pest control technician at Fantastic Pest Control. “Early morning is the best time, because the worms are slower and easier to spot.”

The pros of this method are that it’s simple, low-cost, and effective for small gardens. It also helps detect any pest issues early, before there's any damage to your plants.

On the other hand, checking each leaf by hand can be time-consuming. “This is especially true in larger gardens, and it requires diligence and a keen eye,” says Velev. The long-term benefits include building gardeners' awareness of pest cycles and reducing the need for harmful chemicals.

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Use Companion Planting

Plant herbs and flowers like dill, thyme, nasturtiums, and marigolds near your cabbage. "Bug-repelling plants can deter cabbage worms or attract predators, such as parasitic wasps," says Velev.

This method enhances biodiversity, attracting the natural enemies of cabbage worms, and adds visual appeal to your garden.

However, its effectiveness isn't guaranteed. “This can vary depending on the planting density and local pest pressure,” Velev warns. Companion planting works best when it’s combined with other methods

Employ Diatomaceous Earth

You can also try diatomaceous earth (DE). “This is a natural, soft, sedimentary rock made from the fossilized remains of tiny aquatic organisms,” says Lucke.

To apply it, simply dust the material on and around plant leaves when the plants are dry. It will dehydrate the insect exoskeletons, which will help keep these pests away.

DE must be reapplied after watering or rain. And while it isn’t harmful to humans, it can still irritate your skin and lungs if applied carelessly.

Apply Insect Netting

Another way to stop cabbage worms is by draping lightweight insect netting or row covers over brassica crops. This will prevent the moths from laying eggs on the leaves.

“[It's] a 100 percent physical barrier with no chemicals,” says Lucke. The netting can also reduce heat and sun stress on your plants.

However, there are some drawbacks. You must routinely check the nets to ensure they're safe and secure, which can be a labor-intensive task. It's crucial to ensure that the netting doesn't pose a risk to birds and other wildlife. Additionally, if the nets aren't applied early enough, they may inadvertently trap the cabbage worms among your garden plants. Lastly, netting can reduce airflow and accessibility for weeding or harvesting.