Onions Companion Plants
Onions are a classic companion-planting workhorse because their strong scent is traditionally thought to confuse the flying pests that hunt down neighboring crops. Their upright, narrow tops cast little shade and their roots stay shallow, so they slip in between larger vegetables without much competition. Keep in mind that companion planting is a long-standing garden tradition rather than an exact science, so results will vary with your soil, climate, and pest pressure.
Good companions for Onions
| Plant | Why it helps |
|---|---|
| Carrots | The two are said to mask each other's scent, which may help confuse both onion and carrot root pests. |
| Beets | They share similar care needs and make efficient use of bed space without crowding shallow onion roots. |
| Lettuce | Its low, quick-growing leaves fill the gaps between onion rows and are harvested before the onions bulk up. |
| Cabbage and other brassicas | The pungent onion scent is traditionally believed to help mask cabbage-family plants from some of their pests. |
| Tomatoes | Onions are thought to help deter certain pests that bother tomatoes while taking up little ground space. |
| Strawberries | A long-standing pairing that shares bed space well, since onions add scent without shading the low berry plants. |
| Chamomile | Gardeners have long claimed it boosts onion vigor and flavor while its flowers draw in helpful insects. |
Keep Onions away from
| Plant | Why to separate them |
|---|---|
| Beans | Onions are widely believed to slow the growth of beans and other legumes planted close by. |
| Peas | Like beans, peas are traditionally said to grow poorly when set right next to onions. |
| Asparagus | This heavy-rooted perennial competes for the same space and nutrients, so give it its own bed. |
| Sage | Old garden guidance keeps sage and onions apart, holding that the two grow poorly together. |
Tips
Tuck onions along the edges of beds or between slower crops so their tops get full sun while their shallow roots stay out of the way. Space them so air moves freely, since crowding invites rot, and keep them well away from beans and peas rather than mixing them into the same row. Treat these pairings as a helpful starting point and watch your own garden closely, because outcomes differ from one yard and season to the next.
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Companion planting is a traditional practice; results vary with your climate, soil, and garden. Page updated Aug 4, 2026.