Broccoli Companion Plants
Brassica oleracea var. italica · brassica family · rotation group: brassica
The best companion plants for broccoli are Glossy Collard, White Clover, Radish, Mustard, and Buckwheat. Avoid planting broccoli near Other cabbage-family crops, Strawberry, Pole Bean. Of the 12 pairings recorded here, 5 are supported by published research and 6 are traditional practice with no controlled evidence behind them.
What to plant with broccoli
| Plant | Claimed benefit | Evidence | What the evidence actually shows |
|---|---|---|---|
| Buckwheat | A buckwheat strip feeds parasitoid wasps and predators that attack cabbageworms and aphids. | Research-backed | Extension cites trials in which flowering buckwheat and cowpea raised predator and parasitoid numbers; the measured pest was corn earworm, so the broccoli benefit follows the mechanism rather than a dedicated trial. |
| Glossy Collard | Two perimeter rows of glossy collards intercept diamondback moth before it reaches the broccoli. | Research-backed | One of the best-documented companion tactics anywhere: in nine Florida commercial fields the collard perimeter kept diamondback moth below action thresholds while 60% of unprotected control fields exceeded them, and perimeter-trapped fields used 56% fewer insecticide sprays. Glossy collards work because moths lay 3x more eggs on them yet larval survival is only 6.7% versus 22.2% on cabbage. |
| Mustard | Mustard, arugula and rapeseed act as effective trap crops for brassica pests. | Research-backed | University of Minnesota Extension lists arugula, mustard, rapeseed and napa cabbage as effective brassica trap crops; like radish they must be removed or treated so they do not simply breed more pests. |
| Radish | Radish or daikon sown one to two weeks ahead pulls flea beetles off broccoli seedlings. | Research-backed | Supported by multiple replicated trials and extension IPM guidance. Efficacy depends on sowing the trap early, giving it roughly 10% of the planting area, and destroying it before it becomes a pest reservoir or a clubroot host. |
| White Clover | Undersowing broccoli with white clover as a living mulch sharply reduces pest colonization. | Research-backed | Repeatedly demonstrated at Warwick Crop Centre, and in trials undersown cabbage was harvested to commercial standard without insecticide. The mechanism is visual interference with pest landing, not chemistry — green paper models worked as well as living clover. The catch is competition: clover can reduce head size and must be mown or sown late. |
| Beet | Beets root shallowly between broccoli plants and share few pests with the cabbage family. | Traditional | A sound use of space with no shared pest complex; no measured mutual benefit and none needed for the pairing to be sensible. |
| Dill | Dill left to flower supplies nectar to the parasitic wasps that attack cabbageworm and aphids. | Traditional | The insectary mechanism is genuine and extension recommends pollen-rich umbellifers as beneficial habitat, but no controlled trial measures reduced caterpillar damage on broccoli from dill specifically. |
| Nasturtium | Nasturtium draws cabbage aphids away from broccoli as a sacrificial host. | Traditional | Nasturtium shares the glucosinolate chemistry that attracts brassica pests, which makes the trap-crop idea plausible, but the supporting material is gardener observation and blog reports rather than replicated trials. |
| Mint, rosemary and other aromatic herbs | Strongly scented herbs are said to mask the smell of broccoli and repel cabbage root fly and cabbageworm. | Not supported | Directly tested and not supported. Finch, Billiald and Collier screened 24 non-host plants and found aromatic species — curry plant, marigold, mint, sage, thyme and onion — were no better than non-aromatic ones at disrupting cabbage root fly and onion fly. Green paper models emitting no volatiles worked as well as living clover, showing the effect is visual, not olfactory. Any low green ground cover does the job; the aroma is irrelevant. |
What not to plant with broccoli
| Plant | Claimed problem | Evidence | What the evidence actually shows |
|---|---|---|---|
| Other cabbage-family crops | Clustering brassicas concentrates clubroot, black rot and the whole cabbage pest complex. | Traditional | Extension rotation guidance is emphatic here because clubroot resting spores persist in soil for many years, but the advice is about rotation over seasons rather than a measured penalty from adjacent planting. |
| Pole Bean | Pole beans are said to compete with and shade out broccoli. | Traditional | Shading from a tall trellis is real generic competition, not a specific antagonism; the widely added claim that beans instead feed broccoli nitrogen is also unsupported within the season. |
| Strawberry | Strawberries are the classic charted antagonist of brassicas, said to stunt their growth. | Traditional | One of the most-repeated pairings in companion charts and one of the least supported; no experimental work of any kind was found, and the two have no shared pest or documented allelopathic interaction. |
The honest verdict
Of everything gardeners recommend planting alongside broccoli, 5 pairings have been tested properly: Glossy Collard, White Clover, Radish, Mustard, Buckwheat. Those are the ones worth planning your bed around.
The remaining 3 pairings on this page are traditional practice. They circulate on every companion planting chart online, but we could not find controlled evidence testing them. They are not wrong so much as unverified — most cost nothing to try, and interplanting flowers and herbs has its own well-documented benefit of pulling pollinators and predatory insects into the garden.
Widely repeated, not supported: Mint, rosemary and other aromatic herbs — Directly tested and not supported. Finch, Billiald and Collier screened 24 non-host plants and found aromatic species — curry plant, marigold, mint, sage, thyme and onion — were no better than non-aromatic ones at disrupting cabbage root fly and onion fly. Green paper models emitting no volatiles worked as well as living clover, showing the effect is visual, not olfactory. Any low green ground cover does the job; the aroma is irrelevant.
Every row above links to the publication it came from. See how we grade evidence.
Growing broccoli: the numbers
| Sun | Full sun (6+ hours) |
|---|---|
| Water | Moderate |
| Spacing | 18 in apart · 30 in between rows · 1 per square foot |
| Mature size | about 30 in tall |
| Soil pH | 6–7 |
| Days to maturity | 50–90 days |
| Frost tolerance | Hardy — takes hard frost |
| Containers | Yes — 5 gallon minimum |
| Typical yield | 1 main head plus several weeks of side shoots |
| Common pests | imported cabbageworm, cabbage looper, diamondback moth, cabbage aphid, flea beetles, cabbage maggot |
| Common diseases | black rot, Alternaria leaf and head blight, downy mildew, clubroot, bacterial head rot |
When to plant broccoli
Zone 6b shownStart seeds indoors: Jan 30 – Feb 20 — 7–10 weeks before your last frost
Transplant outdoors: Mar 20 – Apr 2 — 3 weeks before last frost
Direct sow outdoors: Apr 10 – Apr 23 — around your last frost date
Expected harvest: May 9 – Jun 18 — 50–90 days from planting
Fall planting: Jul 28 – Aug 10 — 13 weeks before your first fall frost
Those dates are for zone 6b. Get your own dates by ZIP code →
Varieties worth knowing
seeds- Packman — 50 days, early and heat tolerant, good first spring crop
- Green Magic — 57 days, sets well in warm weather, uniform domed heads
- Belstar — 65 days, strong fall and overwintering performance
- Calabrese — open-pollinated heirloom, smaller main head but prolific side shoots
Variety names link to seeds on Amazon. As an Amazon Associate we earn from qualifying purchases. These are the varieties named in the extension sources for this crop, not a paid placement — where a source recommended a variety for a specific reason, that reason is the note beside it.
Put it in a bed
The garden planner checks every square against this ledger as you place crops — if you drop broccoli next to something recorded as a bad neighbour, the square turns red and tells you why.
Records for the plants named above:
Same rotation group (brassica) — don't follow one with another:
Broccoli companion planting questions
What should not be planted next to broccoli?
How far apart should broccoli be planted?
Does companion planting with broccoli actually work?
When should I plant broccoli?
Sources for this record
- Growing broccoli in home gardens — University of Minnesota Extension
- Broccoli — Clemson Cooperative Extension HGIC
- How to Grow Broccoli in Your Garden — Utah State University Extension
- Soil Temperature Conditions for Vegetable Seed Germination (GN 154) — UC Agriculture and Natural Resources
Record compiled 2026-07. Spot an error or a study we missed? Tell us and we'll correct the entry.