Onions Companion Plants
Onions are traditionally partnered with carrots, as their scent is said to confuse pests searching for either crop. The evidence is limited and the pairing will not replace mesh, crop rotation or regular inspection. Their upright habit does, however, make onions useful among low crops when each plant has enough light and room to dry.
Good companions for Onions
| Plant | Why it helps |
|---|---|
| Carrots | This traditional pairing is said to confuse carrot fly and onion fly through mixed scents, although protection is not assured. |
| Lettuce | Lettuce stays low and can be harvested before onion bulbs need their full share of surface space. |
| Beetroot | Beetroot and onions have contrasting root habits and are often interplanted in orderly rows for efficient bed use. |
| Strawberries | Some gardeners grow onions at strawberry-bed edges, where their upright foliage takes little room and adds diversity. |
| Pot marigolds | Pot marigolds at the edge provide accessible flowers for insects without heavily shading onion foliage. |
| Chamomile | Chamomile is traditionally included near onions for diversity, though specific growth benefits are largely anecdotal. |
Keep Onions away from
| Plant | Why to separate them |
|---|---|
| Peas | Onions and peas are commonly kept apart because alliums are traditionally thought to check pea growth. |
| Broad beans | Broad beans are another legume often separated from onions in traditional companion-planting plans. |
| Asparagus | Both crops need clear, well-managed ground, and onion cultivation can disturb an established asparagus bed. |
Tips
Plant onions in a sunny, open site where foliage dries quickly after rain. Keep the necks clear of mulch and avoid overwatering as bulbs mature. If alternating with carrots, retain enough space to weed and thin both crops. Do not rely on scent alone where onion fly has been troublesome; use rotation and timely checks.
Onions companion planting: frequently asked questions
What are good companion plants for onions?
Good companions for onions include Carrots, Lettuce, Beetroot, Strawberries, Pot marigolds, Chamomile.
What should you not plant near onions?
Keep onions away from Peas, Broad beans, Asparagus.
How does companion planting help onions?
Onions are traditionally partnered with carrots, as their scent is said to confuse pests searching for either crop.
← All companion planting guides
Companion planting is a traditional practice; results vary with your climate, soil and garden. Page updated 18 Sep 2026.