Tradition
Bad
avoidgood
1 chart entry: 0 recommend, 1 advise against.
All entries cite a source.
Onion
Allium cepa
Amaryllidaceae
Bean
Phaseolus vulgaris
FabaceaeCan you plant onions and beans together?
Yes. Garden charts say to keep beans away from onions, but the tests we found say otherwise. A shared bed gave about 43% more harvest than separate beds in one field trial. That rests on a single study, so treat it as a lead, not a rule.
Why the tests and the charts disagree
More harvest from the same bed. In one field trial, a bed with both crops gave about 43% more harvest than the same space split into a bean bed and a onion bed.
Productivity, Quality and Profit of Sole or Intercropped Green Beau (Phaseolus vulgaris L.) (Abou-Hussein Sd · 2005)Garden charts advise against it. 1 garden chart entry says to keep them apart. Charts pass on gardening tradition; they are not tests.
The Best Onion Companion Plants (2022 · Growfully)
What to plant with onions and beans
Good neighbours of both, best tested first.
LettuceWith onions: Recommended by garden charts, not testedWith beans: 48% more harvest
TomatoWith onions: Better soil and nutrient uptakeWith beans: 18% more harvest
CucumberWith onions: Helpful plant chemistryWith beans: 14% more harvest
DillWith onions: Draws in pest-eating insectsWith beans: Fewer pests
CauliflowerWith onions: Bigger combined harvestWith beans: Bigger combined harvest
What to keep away from onions and beans
The evidence in detail
For readers who want to dig in: every chart entry, study and yield trial behind the answer above, with the numbers.
Tradition, research and yield trials
Research
No papers found on this pair.
Yield trial
Good
0.45
0.97
Bean gains more. Partial LER is each crop's share of the yield it would give alone.
1 field trial. Published LERs lean high.
Myth busted
What happens above and below ground
Each animation illustrates a mechanism a study reported for this pair. Pick a card to focus on it.
Everything at once.
Companion plants for both onions and beans
Plants that are good neighbours of each. Biggest harvest gain first; each cell links to the evidence for that pair.
| Plant | With onions | With beans |
|---|---|---|
| Lettuce | No trial foundNot tested. Charts: recommend.Evidence for onions and lettuce | 48% more harvest from the same spaceField trial, 2 studies. Charts: recommend.Evidence for beans and lettuce |
| Tomato | Better soil and nutrient uptake and bigger combined harvestMixed results on soil and nutrientsField trial, 7 studies. Charts: not listed.Evidence for onions and tomatoes | 18% more harvest from the same spaceField trial, 2 studies. Charts: recommend.Evidence for beans and tomatoes |
| Cucumber | Helpful plant chemistry and bigger combined harvestField trial, 3 studies. Charts: recommend.Evidence for onions and cucumbers | 14% more harvest from the same spaceField trial, 1 study. Charts: recommend.Evidence for beans and cucumbers |
| Dill | Draws in pest-eating insectsField trial, 1 study. Charts: recommend.Evidence for onions and dill | Fewer pests, better soil and nutrient uptake and bigger combined harvestField trial, 5 studies. Charts: not listed.Evidence for beans and dill |
| Cauliflower | Bigger combined harvestField trial, 1 study. Charts: not listed.Evidence for onions and cauliflower | Bigger combined harvestField trial, 1 study. Charts: recommend.Evidence for beans and cauliflower |
Harvest from the same space compares a bed with both crops against the same area split into single-crop beds, counting the harvest of both crops (the land equivalent ratio in yield trials).
The evidence, with sources
- GoodLER 1.43field trialEgypt, 2003-2004; Additive design; median LER 1.43 over 2 treatment(s) · partial LER Bean 0.97, Onion 0.45Productivity, Quality and Profit of Sole or Intercropped Green Beau (Phaseolus vulgaris L.) (Abou-Hussein Sd · 2005)
- Badadvises againstOnion: avoid beansThe Best Onion Companion Plants (2022 · Growfully)
All neighbours of onion and of bean, or every pair at once in the companion planting chart.
Have you grown onions and beans together?
Tell other gardeners what happened: spacing, pests, harvest, or ask a question. Reader notes are not checked by us and do not change the verdicts on this page.