Record — updated 2026-07

Spinach Companion Plants

Entry No. 030

Spinacia oleracea · goosefoot family · rotation group: leafy

The best companion plants for spinach are Radish, Buckwheat, Sweet Alyssum, White Clover, and Pea. Avoid planting spinach near Beet, Swiss Chard, Potato, Fennel. Of the 12 pairings recorded here, 2 are supported by published research and 10 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 spinach

Companion plants for spinach — 2 research-backed, 6 traditional
Plant Claimed benefit Evidence What the evidence actually shows
Buckwheat A nearby buckwheat strip feeds hoverflies, lacewings and parasitoid wasps that attack spinach aphids. Research-backed University of Minnesota Extension cites trials in which flowering buckwheat and cowpea measurably increased predator and parasitoid numbers; the tested target pest was corn earworm, so the aphid benefit is extrapolated from the same mechanism.
Radish Fast-maturing radishes use the between-row space before spinach fills in, and pull flea beetles off the spinach. Research-backed Radish and daikon are repeatedly confirmed as effective flea beetle trap crops in replicated trials, but nearly all of that work used brassica cash crops rather than spinach, so the transfer is an inference.
Cilantro Cilantro allowed to flower supplies pollen and nectar to ladybugs and parasitic wasps. Traditional Virginia Cooperative Extension describes pollen-rich umbellifers as beneficial-insect habitat, but cites no trial quantifying pest reduction on a neighbouring crop.
Onion Onions are said to deter leafminers and aphids from adjacent spinach. Traditional No controlled support found; a Scientific Reports study of leek grown beside sweet pepper found allium volatiles disrupted aphid feeding but actually raised aphid survival and fecundity, so allium 'repellency' should not be assumed.
Pea Peas share spinach's cool-season window and a pea trellis casts light afternoon shade that delays bolting. Traditional The shared season and shading are real horticultural effects, but no trial has measured a bolt-delay benefit; the frequently added claim that pea nitrogen feeds the spinach is not supported.
Strawberry Strawberries and spinach occupy different soil layers and are often interplanted in the same bed. Traditional A very common recommendation with no controlled evidence found; the only defensible rationale is spatial, not biochemical.
Sweet Alyssum Low-growing alyssum flowers all season and supports syrphid flies whose larvae eat aphids. Traditional The underlying insectary mechanism is well supported, but no controlled trial pairing alyssum specifically with spinach was found; treat the aphid benefit as plausible rather than demonstrated.
White Clover Undersown as a living mulch, clover reduces the number of pest insects that successfully land on the crop. Traditional The living-mulch effect is solidly demonstrated in brassicas at Warwick Crop Centre, but has not been tested on spinach, and clover competition can cut leaf yield if it is not mown or managed.

What not to plant with spinach

Plants to keep away from spinach
Plant Claimed problem Evidence What the evidence actually shows
Beet Beets are in the same family and host the same spinach leafminer and Cercospora leaf spot. Traditional The rotation principle — don't cluster crops that share pests and diseases — is standard extension guidance, but no study has measured the in-season penalty of planting beets beside spinach specifically.
Fennel Fennel is claimed to release root compounds that inhibit most vegetable neighbours. Traditional Fennel allelopathy is documented in laboratory germination assays, but no field trial was found showing garden-scale suppression of spinach.
Potato Potatoes are said to stunt spinach through competition and heavy shade. Traditional Repeated across garden charts with no supporting trial; competition for light and water is the only plausible mechanism and applies to any tall neighbour.
Swiss Chard Chard is the same species group as beet and shares spinach's leafminer and leaf-spot problems. Traditional Same reasoning as beet; sound rotation logic, no controlled adjacency data.

The honest verdict

Of everything gardeners recommend planting alongside spinach, 2 pairings have been tested properly: Radish, Buckwheat. 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 spinach: the numbers

Field data — Spinach
SunFull sun (6+ hours)
WaterModerate
Spacing4 in apart · 14 in between rows · 9 per square foot
Mature sizeabout 10 in tall
Soil pH6–7
Days to maturity37–48 days
Frost toleranceHardy — takes hard frost
ContainersYes — 2 gallon minimum
Typical yield4-6 lb per 10-ft row
Common pestsspinach leafminer, aphids, flea beetles, slugs, cutworms
Common diseasesdowny mildew, white rust, damping-off, cucumber mosaic virus

When to plant spinach

Zone 6b shown
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Start indoors Sow / transplant outdoors Harvest

Start seeds indoors: Feb 27 – Mar 6 — 5–6 weeks before your last frost

Direct sow outdoors: Mar 20 – Apr 2 — 3 weeks before last frost

Transplant outdoors: Apr 10 – Apr 23 — around your last frost date

Expected harvest: May 17 – May 28 — 37–48 days from planting

Fall planting: Sep 8 – Sep 21 — 7 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 spinach 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 (leafy) — don't follow one with another:

Spinach companion planting questions

What should not be planted next to spinach?
Beet, Swiss Chard, Potato, Fennel. Beets are in the same family and host the same spinach leafminer and Cercospora leaf spot. The rotation principle — don't cluster crops that share pests and diseases — is standard extension guidance, but no study has measured the in-season penalty of planting beets beside spinach specifically.
How far apart should spinach be planted?
Space spinach about 4 inches apart in the row, with 14 inches between rows. In a square-foot bed that works out to 9 plants per square foot.
Does companion planting with spinach actually work?
Partly. 2 of the pairings on this page are backed by published research — Radish, Buckwheat. 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 spinach?
Start seed indoors 5–6 weeks before your last frost. Direct sow outdoors 3 weeks before last frost. In zone 6b that means roughly Mar 20 – Apr 2. 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.