Tradition
No chart mentions this pair.
Cauliflower
Brassica oleracea var. botrytis
Brassicaceae
Onion
Allium cepa
AmaryllidaceaeCan you plant cauliflower and onions together?
Yes. Cauliflower and onions grow well together. Growing them together gave a bigger combined harvest in a field trial. That rests on a single study, so treat it as a lead, not a rule.
Why cauliflower and onions work together
Bigger combined harvest. In a field trial, growing them together gave a bigger combined harvest.
What to plant with cauliflower and onions
Good neighbours of both, best tested first.
What to keep away from cauliflower and onions
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
Good
avoidgood
1 paper found: 1 positive, 0 negative.
yield / land use
auto-classified not reviewed by a person
Yield trial
No intercropping yield trial.
Good neighbours
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 cauliflower and onions
Plants that are good neighbours of each. Biggest harvest gain first; each cell links to the evidence for that pair.
| Plant | With cauliflower | With onions |
|---|---|---|
 Cabbage | No trial foundSame family (Brassicaceae): shares pests and diseasesNot tested. Charts: recommend.Evidence for cauliflower and cabbage | Fewer pests and draws in pest-eating insects8% more harvest from the same spaceField trial, 8 studies. Charts: recommend.Evidence for onions and cabbage |
 Broccoli | Lures pests awaySame family (Brassicaceae): shares pests and diseasesField trial, 2 studies. Charts: not listed.Evidence for cauliflower and broccoli | No trial foundNot tested. Charts: recommend.Evidence for onions and broccoli |
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
- Goodyield / land usefield trialauto-classifiedIntercropping based on cauliflower: more productive, profitable and highly sustainableIntercropping based on cauliflower: More productive, profitable and highly sustainable (Yildirim · 2005)Relevance 97% · effect confidence 77%
All neighbours of cauliflower and of onion, or every pair at once in the companion planting chart.
Have you grown cauliflower and onions 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.