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Onions are a staple in the kitchen, showing up in everything from soups to stir-fries, which is exactly why they’ve earned a spot in so many home gardens. But beyond the kitchen, onions offer something even more useful in the garden: natural pest control. Their strong scent helps deter a wide range of common insect pests, making them a valuable companion for more delicate or pest-prone plants.
Because onions don’t take up much space and have relatively simple growing needs, they fit easily into many parts of the garden. They’re especially helpful when planted near vegetables that benefit from their protective properties. If you’re looking to make the most of your garden space and naturally reduce pest pressure, planting onions alongside the right companions can go a long way.
Here are 14 plants that grow especially well next to onions.
Spinach
Onions are a classic companion for spinach. They repel pests with their strong smell. Plus, their shallow root systems won’t compete much with spinach, which also stays close to the soil surface.
Strawberries
Strawberries can be magnets for garden pests, but planting onions nearby offers a natural line of defense. The strong smell of onions helps deter many of the insects that tend to bother strawberry plants.
Since both onions and strawberries grow low to the ground, they don’t compete much for sunlight or space. Onions also have a tidy, upright growth habit so they won’t crowd out your berries or hog moisture.
Watermelon
The strong scent of onions will help deter aphids and other pests. Try planting rows of onions around the borders of your watermelon plot to create an aromatic defense barrier.
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Cantaloupe
Onions grow well with cantaloupes. Their sharp smell repels aphids and thrips while occupying minimal space above the soil. Plant sets or seedlings in a ring around each cantaloupe mound, with each bulb 4 inches apart.
Provide full sun and loose, fertile soil. Also, weed regularly so onion roots aren’t crowded, and stop watering once the tops flop to cure the bulbs before storage.
Tomatillos
Onions and tomatillos grow well together because they are mutually beneficial to each other. Onions are known for their pungent smell, which deters pests that might harm tomatillo plants.
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Kale
Onions act as a natural insect deterrent due to their strong sulfur scent. They help mask the smell of kale and keep aphids, slugs, and cabbage worms at bay. Since they grow tall and narrow, they don’t crowd out kale.
Bell Peppers
Growing onions near bell peppers is highly beneficial. The scent of onions helps keep away pests that usually target bell peppers. Onions won’t overshadow your bell peppers or compete for water. This makes onions an excellent companion for co-planting.
Artichoke
Onions are excellent pest deterrents and do exceptionally well when tucked near the base of artichokes. They emit a pungent aroma that repels pests like aphids, thrips, flea beetles, and even root maggots. Because they have narrow, vertical growth, onions won’t interfere with the broad leaves of artichokes.
Lettuce
Onions are a natural pest deterrent, especially against slugs that commonly target lettuce and other soft-leaved vegetable crops. Their tall, narrow growth habit means they won’t crowd out your greens. For the best results, plant alternating rows of lettuce and onions.
Carrot
Planting onions near carrots offers significant benefits. The scent of onions helps keep away pests that usually target carrots. This makes onions an excellent companion for co-planting with carrots. This pairing keeps both the alliums and carrots healthier and free from pests.
Cabbage
Onions are a great companion plant for cabbage because their pungent scent deters pests such as cabbage worms and maggots. However, it’s essential to note that the essential oils from onions may not be compatible with other plants in your garden, so exercise caution.
Blueberry Bushes
Having onions near blueberry bushes is highly beneficial. The scent of onions helps repel pests that typically target blueberry plants. As members of the allium family, onions won’t overshadow your blueberries or compete for water. This makes onions an excellent companion for co-planting with blueberries.
Leek
Since both onions and leeks naturally repel many common garden pests, they tend to grow well side by side without problems. Their similar growing habits and soil needs make them an easy pairing, and planting them in the same bed can help streamline your garden care routine.
Squash
Onions make a great border plant for squash. Their strong scent confuses and repels aphids, beetles, and other pests that love to feed on squash leaves and stems.
Since onions have a shallow root system and grow upright, they don’t crowd out squash plants. They’re especially useful planted around the outer edge of your squash patch to form a natural protective barrier.
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