Kale Companion Plants
Brassica oleracea var. acephala · brassica family · rotation group: brassica
The best companion plants for kale are Glossy Collard, White Clover, Radish, Mustard, and Buckwheat. Avoid planting kale near Other cabbage-family crops, Strawberry, Pole Bean. Of the 11 pairings recorded here, 5 are supported by published research and 6 are traditional practice with no controlled evidence behind them.
What to plant with kale
| Plant | Claimed benefit | Evidence | What the evidence actually shows |
|---|---|---|---|
| Buckwheat | Buckwheat feeds parasitoids and predators that attack aphids and cabbageworms on kale. | Research-backed | Extension cites trials showing flowering buckwheat and cowpea raise natural-enemy numbers; the kale-specific effect is inferred from the mechanism. |
| Glossy Collard | Collards planted as a perimeter absorb diamondback moth pressure that would otherwise hit the kale. | Research-backed | The trap-crop effect is well demonstrated, though note the trial caveat: kale and cabbage grown within 30 cm of the trap crop weighed less, so leave about 60 cm between trap and cash crop. |
| Mustard | Mustard and arugula divert brassica pests away from the kale planting. | Research-backed | Extension names mustard, arugula, rapeseed and napa cabbage as effective brassica trap crops; the trap must be destroyed or sprayed or it simply raises the next generation. |
| Radish | Radish sown a week or two early pulls flea beetles off kale, which is highly susceptible when young. | Research-backed | Radish and daikon trap cropping is supported by multiple trials; flea beetle is one of kale's worst seedling pests, making this among the more useful evidence-backed pairings in the dataset. |
| White Clover | Undersowing kale with clover cuts colonization by cabbage aphid and caterpillar pests. | Research-backed | Demonstrated across brassicas at Warwick; the mechanism is disrupted landing behaviour rather than repellency, so any low green cover works. Watch competition, and keep clover trimmed back from young plants. |
| Beet | Beets share the cool season with kale and have no pests in common with it. | Traditional | Sensible spatial pairing; no measured interaction in either direction. |
| Dill | Dill in flower supplies nectar to wasps that parasitise cabbageworm larvae on kale. | Traditional | Real mechanism, no kale-specific trial; treat as habitat improvement rather than pest control. |
| Nasturtium | Nasturtium draws cabbage aphids off kale as a preferred host. | Traditional | Chemistry makes it plausible and gardeners report a strong aphid preference, but the supporting material is observational rather than a replicated trial. |
What not to plant with kale
| Plant | Claimed problem | Evidence | What the evidence actually shows |
|---|---|---|---|
| Other cabbage-family crops | Neighbouring brassicas concentrate clubroot, black rot and the shared caterpillar complex. | Traditional | Sound rotation guidance rather than a measured adjacency penalty; clubroot is the reason extension insists on multi-year gaps. |
| Pole Bean | Pole beans are said to check kale's growth. | Traditional | Generic shading competition, no specific evidence; kale actually tolerates part shade better than most brassicas, which weakens the concern. |
| Strawberry | Strawberries are the traditional charted antagonist of all brassicas. | Traditional | No experimental support of any kind; the pairing persists because early companion books repeated it. |
The honest verdict
Of everything gardeners recommend planting alongside kale, 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.
Every row above links to the publication it came from. See how we grade evidence.
Growing kale: the numbers
| Sun | Full sun (6+ hours) |
|---|---|
| Water | Moderate |
| Spacing | 12 in apart · 24 in between rows · 1 per square foot |
| Mature size | about 24 in tall |
| Soil pH | 6–7.5 |
| Days to maturity | 50–82 days |
| Frost tolerance | Hardy — takes hard frost |
| Containers | Yes — 3 gallon minimum |
| Typical yield | cut-and-come-again leaves over many weeks; 3-5 lb per 10-ft row |
| Common pests | flea beetles, imported cabbageworm, cabbage looper, diamondback moth, cabbage aphid, harlequin bug |
| Common diseases | Alternaria leaf spot, black rot, clubroot, downy mildew |
When to plant kale
Zone 6b shownStart seeds indoors: Jan 23 – Feb 13 — 8–11 weeks before your last frost
Transplant outdoors: Mar 13 – Mar 26 — 4 weeks before last frost
Direct sow outdoors: Mar 13 – Mar 26 — 4 weeks before last frost
Expected harvest: May 2 – Jun 3 — 50–82 days from planting
Fall planting: Aug 4 – Aug 17 — 12 weeks before your first fall frost
Those dates are for zone 6b. Get your own dates by ZIP code →
Varieties worth knowing
seeds- Red Russian — 50 days, tender flat leaves, Brassica napus type, very cold hardy
- Winterbor — 52 days, finely curled, outstanding overwintering hardiness
- Lacinato / Dinosaur — strap-shaped blue-green savoyed leaves, classic Tuscan type, holds texture when cooked
- Vates Blue Scorch — 55 days, curled, resists bolting and cold damage
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 kale 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:
Kale companion planting questions
What should not be planted next to kale?
How far apart should kale be planted?
Does companion planting with kale actually work?
When should I plant kale?
Sources for this record
- Growing collards and kale in home gardens — University of Minnesota Extension
- How to Grow Kale in Your Garden — Utah State University Extension
- Arugula, Kale, Mesclun, Mustard, and Swiss Chard — Clemson Cooperative Extension HGIC
- Kale (Brassica oleracea Acephala group) — University of Illinois Hort Answers
Record compiled 2026-07. Spot an error or a study we missed? Tell us and we'll correct the entry.