Record — updated 2026-07

Pea Companion Plants

Entry No. 023

Pisum sativum · legume family · rotation group: legume

The best companion plants for pea are Buckwheat, Sweet Corn, Radish, Spinach, and Carrot. Avoid planting pea near Garlic, Onion, Other legumes. Of the 11 pairings recorded here, 2 are supported by published research and 9 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 pea

Companion plants for pea — 2 research-backed, 6 traditional
Plant Claimed benefit Evidence What the evidence actually shows
Buckwheat A buckwheat strip near the pea row feeds parasitoids and predators of pea aphid. Research-backed Extension cites trials in which flowering buckwheat and cowpea raised predator and parasitoid populations; the measured target was corn earworm, so the pea aphid benefit follows the mechanism rather than a direct trial.
Source: Companion planting in home gardens — University of Minnesota Extension
Sweet Corn In a Three Sisters-style planting, corn supplies support for climbing legumes and the mixture out-yields the same area in monoculture. Research-backed Land equivalent ratios above 1 are documented for the maize/bean/squash polyculture, driven by root-niche complementarity — but the trials used climbing common bean, not garden pea, and corn's summer timing rarely overlaps a spring pea crop.
Source: Root foraging elicits niche complementarity-dependent yield advantage in the ancient 'three sisters' (maize/bean/squash) polyculture, Annals of Botany (2014)
Cabbage-family crops Brassicas planted after peas are said to take up the nitrogen the peas fixed. Traditional This works as a rotation, not as a same-season companion: the nitrogen becomes plant-available only once pea roots and residues decompose, so the benefit accrues to the following crop.
Source: Belowground nitrogen transfer from legumes to non-legumes under managed herbaceous cropping systems. A review — Agronomy for Sustainable Development 36:58 (2016)
Carrot Carrots occupy the ground beneath the pea trellis and are unaffected by the peas above. Traditional Spatial complementarity only; the often-added nitrogen benefit does not apply in the same season.
Source: Garden Peas — Clemson Cooperative Extension HGIC
Lettuce Lettuce shares the cool season and benefits from shade at the base of the pea row. Traditional Plausible microclimate effect, no controlled data.
Source: Garden Peas — Clemson Cooperative Extension HGIC
Radish Radish is sown in the same early window and harvested before peas fill the trellis. Traditional Straightforward succession use of space; no biological interaction claimed or found.
Source: Growing peas in home gardens — University of Minnesota Extension
Spinach Spinach grows in the partial shade cast by a pea trellis as spring warms. Traditional The shading effect is real and useful for delaying bolt, but it has not been quantified; note this is a light-management benefit, not a nutrient one.
Source: Growing peas in home gardens — University of Minnesota Extension
Sweet Alyssum Alyssum at the foot of the trellis supports hoverflies that attack pea aphid colonies. Traditional Follows the evidenced insectary principle but no pea-specific trial was found.
Source: Companion planting in home gardens — University of Minnesota Extension

What not to plant with pea

Plants to keep away from pea
Plant Claimed problem Evidence What the evidence actually shows
Garlic Alliums are said to inhibit pea growth and disrupt rhizobial nodulation. Traditional Universally repeated in companion charts but sourced only to garden guides; allium allelochemicals inhibit seedlings in laboratory assays and no field trial confirming garden-scale suppression of peas was found.
Source: Companion Planting in Gardening (SPES-620) — Virginia Cooperative Extension
Onion Onions are the most-cited pea antagonist in traditional charts. Traditional Same evidential status as garlic — plausible allelopathic mechanism, no controlled field data.
Source: Companion planting in home gardens — University of Minnesota Extension
Other legumes Repeatedly following peas with beans or other legumes builds up root rot and white mould. Traditional Extension advises rotating away from legumes to manage soilborne root rot; this is well-founded rotation practice, though not a tested same-season adjacency effect.
Source: Growing peas in home gardens — University of Minnesota Extension

The honest verdict

Of everything gardeners recommend planting alongside pea, 2 pairings have been tested properly: Buckwheat, Sweet Corn. Those are the ones worth planning your bed around.

The remaining 6 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 pea: the numbers

Field data — Pea
SunFull sun (6+ hours)
WaterModerate
Spacing2 in apart · 24 in between rows · 8 per square foot
Mature sizeabout 48 in tall
Soil pH6–7
Days to maturity55–75 days
Frost toleranceHardy — takes hard frost
ContainersYes — 5 gallon minimum
Typical yieldabout 1 bushel per 50 ft of row
Common pestspea aphid, cutworms, pea weevil, thrips
Common diseasespowdery mildew, white mould, Fusarium root rot, pea enation mosaic virus

When to plant pea

Zone 6b shown
J
F
M
A
M
J
J
A
S
O
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Start indoors Sow / transplant outdoors Harvest

Direct sow outdoors: Mar 6 – Mar 19 — 5 weeks before last frost

Expected harvest: Apr 30 – May 20 — 55–75 days from planting

Fall planting: Aug 25 – Sep 7 — 9 weeks before your first fall frost

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

Varieties worth knowing

seeds

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

Records for the plants named above:

RadishSpinachCarrotLettuceSweet CornSweet Alyssum

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

Bush beanPole bean

Pea companion planting questions

What should not be planted next to pea?
Garlic, Onion, Other legumes. Alliums are said to inhibit pea growth and disrupt rhizobial nodulation. Universally repeated in companion charts but sourced only to garden guides; allium allelochemicals inhibit seedlings in laboratory assays and no field trial confirming garden-scale suppression of peas was found.
How far apart should pea be planted?
Space pea about 2 inches apart in the row, with 24 inches between rows. In a square-foot bed that works out to 8 plants per square foot.
Does companion planting with pea actually work?
Partly. 2 of the pairings on this page are backed by published research — Buckwheat, Sweet Corn. 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 pea?
Direct sow outdoors 5 weeks before last frost. In zone 6b that means roughly Mar 6 – Mar 19. 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.