Record — updated 2026-07

Nasturtium Companion Plants

Entry No. 054

Tropaeolum majus · nasturtium family family · rotation group: other

The best companion plants for nasturtium are Squash, Cabbage and Broccoli, Bean, Tomato and Tomato. Of the 4 pairings recorded here, 1 is supported by published research and 3 are traditional practice with no controlled evidence behind them.

Research-backed tested in controlled research Traditional long practice, untested Not supported tested and not supported

What to plant with nasturtium

Companion plants for nasturtium — 1 research-backed, 3 traditional
Plant	Claimed benefit	Evidence	What the evidence actually shows
Squash	Nasturtium interplanted with squash reduces squash bug and cucumber beetle numbers.	Research-backed	The best-supported nasturtium claim: UMN Extension states this age-old practice is supported by research showing nasturtium can help reduce squash bug populations, citing an Iowa study that also covered cucumber beetles. Source: Companion planting in home gardens, University of Minnesota Extension
Bean	Nasturtium concentrates black bean aphids away from bean plants.	Traditional	Consistent with nasturtium's documented attractiveness to aphids; the crop-protection step is untested. Source: Wolfe, K. (2020), Trap Cropping, WSU Extension Master Gardeners
Cabbage and Broccoli	Nasturtium acts as a trap crop, pulling aphids and cabbage white caterpillars off brassicas.	Traditional	WSU Extension does list nasturtium as a trap crop for aphids and flea beetles, and aphids clearly prefer it, but no controlled trial quantifies the protection given to the main crop in a home garden. Source: Wolfe, K. (2020), Trap Cropping, WSU Extension Master Gardeners
Tomato	Nasturtium interplanted with tomatoes reduces whitefly and aphid pressure.	Traditional	No trial support; nasturtium is itself a documented whitefly and aphid host, so it may add pest pressure rather than remove it. Source: Tropaeolum majus, NC State Extension Gardener Plant Toolbox

The honest verdict

Of everything gardeners recommend planting alongside nasturtium, 1 pairing has been tested properly: Squash. 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.

Other recorded effects

Effects that aren't about a neighbouring plant — what nasturtium does for (or to) the garden around it, and the caveats attached to the popular versions of those claims.

Recorded effects and caveats — Nasturtium
Effect	The claim	Evidence	What the evidence actually shows
Cabbage Looper and Imported Cabbageworm	Nasturtium reduces looper and cabbageworm pressure on brassicas.	Research-backed	Listed by UMN Extension among the research-backed nasturtium pairings, alongside squash bugs and cucumber beetles. Source: Companion planting in home gardens, University of Minnesota Extension
Flea Beetle Trap	Nasturtium draws flea beetles away from young brassica and eggplant seedlings.	Traditional	Listed by WSU Extension among trap crops for flea beetles; effectiveness in a small garden is unquantified. Source: Wolfe, K. (2020), Trap Cropping, WSU Extension Master Gardeners
Pollinators and Hummingbirds	Nasturtium flowers attract hummingbirds, butterflies and pollinators.	Research-backed	Documented by NC State Extension as a nectar plant for hummingbirds, butterflies and other pollinators. Source: Tropaeolum majus, NC State Extension Gardener Plant Toolbox
Unmanaged Nasturtium	A nasturtium trap crop can be planted and left alone.	Not supported	Explicitly warned against: if the trap crop is left unattended the pests continue to reproduce and multiply, making the problem worse. Infested plants or plant parts must be removed. Source: Wolfe, K. (2020), Trap Cropping, WSU Extension Master Gardeners
Nasturtium as a Pest Repellent	Nasturtium repels garden pests.	Not supported	The mechanism is the opposite of repellency: nasturtium attracts aphids, whiteflies and cabbage whites. Extension sources classify it as a trap crop, never as a repellent. Source: Tropaeolum majus, NC State Extension Gardener Plant Toolbox

Growing nasturtium: the numbers

Field data — Nasturtium
Sun	Full sun (6+ hours)
Water	Low once established
Spacing	10 in apart · 18 in between rows · 1 per square foot
Mature size	about 12 in tall
Soil pH	6–7.5
Days to maturity	55–65 days
Frost tolerance	Tender — killed by frost
Containers	Yes — 2 gallon minimum
Common pests	aphids, whiteflies, cabbage white caterpillars, mealybugs
Common diseases	bacterial wilt, leaf spot

When to plant nasturtium

Zone 6b shown

Start indoors Sow / transplant outdoors Harvest

Start seeds indoors: Mar 13 – Mar 20 — 3–4 weeks before your last frost

Transplant outdoors: Apr 17 – Apr 30 — 1 week after last frost

Direct sow outdoors: Apr 17 – Apr 30 — 1 week after last frost

Expected harvest: Jun 11 – Jun 21 — 55–65 days from planting

Those dates are for zone 6b. Get your own dates by ZIP code →

Varieties worth knowing

seeds

Empress of India — compact crimson flowers with dark blue-green foliage
Jewel of Africa — climbing type reaching about 8 feet
Whirlybird — semi-double upfacing flowers on bushy plants
Alaska — cream-variegated foliage; ornamental even out of bloom

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 nasturtium next to something recorded as a bad neighbour, the square turns red and tells you why.

Records for the plants named above:

Bean Squash Tomato

Same rotation group (other) — don't follow one with another:

Asparagus Celery Okra Rhubarb Sweet corn Sweet Potato

Nasturtium companion planting questions

What should not be planted next to nasturtium?

We have no well-evidenced antagonists on file for nasturtium. The reliable rule is to avoid crowding it with anything in its own family (nasturtium family), which shares its pests and diseases and makes rotation harder.

How far apart should nasturtium be planted?

Space nasturtium about 10 inches apart in the row, with 18 inches between rows. In a square-foot bed that works out to 1 plant per square foot.

Does companion planting with nasturtium actually work?

Partly. 1 of the pairings on this page are backed by published research — Squash. The rest are traditional practice: plausible, harmless to try, but untested. Treat the folklore as a starting point rather than a rule, and read what the evidence says about companion planting.

When should I plant nasturtium?

Start seed indoors 3–4 weeks before your last frost. Transplant outdoors 1 week after last frost. In zone 6b that means roughly Apr 17 – Apr 30. Get exact dates for your ZIP code →

Sources for this record

Record compiled 2026-07. Spot an error or a study we missed? Tell us and we'll correct the entry.