Tomato

Solanum lycopersicum

Solanaceae

Cucumber

Cucumis sativus

Cucurbitaceae

Can you plant tomatoes and cucumbers together?

Yes. Tomatoes and cucumbers grow well together. A shared bed gave about 17% more harvest than separate beds in 2 field trials, and cucumbers lured pests away from tomatoes in a field trial.

Why tomatoes and cucumbers work together

More harvest from the same bed. In 2 field trials, a bed with both crops gave about 17% more harvest than the same space split into a cucumber bed and a tomato bed.
An experiment in intercropping cucumbers and tomatoes in Southern Michigan, U.S.A. (Schultz · 1982)
and 1 more source
Lures pests away. In a field trial, cucumbers lured pests away from tomatoes.
Effect of intercropping on tomato yellow leaf curt virus incidenceon tomato (Yin Xiangui · 2002 · Xi nan nong ye xue bao = Southwest China journal of agricultural sciences)
Garden charts recommend it. 1 garden chart entry recommends growing them together. It cites no source. Charts pass on gardening tradition; they are not tests.
List of companion plants (uncited entry) (Wikipedia)
No clear effect on soil and nutrients. In a greenhouse or pot trial, growing them together made no clear difference to soil and nutrients.
The intercropping partner affects arbuscular mycorrhizal fungi and Fusarium oxysporum f. sp. lycopersici interactions in tomato (Hage-Ahmed · 2013 · Mycorrhiza)

What to plant with tomatoes and cucumbers

Good neighbours of both, best tested first.

BeanWith tomatoes: 18% more harvestWith cucumbers: 14% more harvest
OnionWith tomatoes: Better soil and nutrient uptakeWith cucumbers: Helpful plant chemistry
GarlicWith tomatoes: Recommended by garden charts, not testedWith cucumbers: Bigger combined harvest
CeleryWith tomatoes: Recommended by garden charts, not testedWith cucumbers: Fewer pests

How each one was tested, with the evidence

What to keep away from tomatoes and cucumbers

RosemaryWith tomatoes: Garden charts advise against it, not tested
PotatoWith cucumbers: Garden charts advise against it, not tested

The evidence in detail

For readers who want to dig in: every chart entry, study and yield trial behind the answer above, with the numbers.

Tradition, research and yield trials

Tradition

Good

avoidgood

1 chart entry: 1 recommend, 0 advise against.

0 cited, 1 uncited.

Research

Good

avoidgood

2 papers found: 1 positive, 0 negative, 1 no effect.

nutrients / soiltrap crop

auto-classified not reviewed by a person

Yield trial

Good

0.68

0.45

Tomato gains more. Partial LER is each crop's share of the yield it would give alone.

2 field trials. Published LERs lean high.

Good neighbours

What happens above and below ground

Each animation illustrates a mechanism a study reported for this pair. Pick a card to focus on it.

Everything at once.

What is going on (3)

Pick a card to spotlight its animation in the scene.

Cucumber TomatoCucumber is a decoy: pests settle on it and leave Tomato alone.

Researchfield trial x1

Effect of intercropping on tomato yellow leaf curt virus incidenceon tomato (Yin Xiangui · 2002 · Xi nan nong ye xue bao = Southwest China journal of agricultural sciences)

Tomato Cucumber No clear effectStudies looked for nutrients / soil from Tomato to Cucumber and found no clear effect.

Cucumber Tomato No clear effectStudies looked for nutrients / soil from Cucumber to Tomato and found no clear effect.

Researchgreenhouse / pot trial x1

The intercropping partner affects arbuscular mycorrhizal fungi and Fusarium oxysporum f. sp. lycopersici interactions in tomato (Hage-Ahmed · 2013 · Mycorrhiza)

Tomato CucumberMedian land equivalent ratio 1.17 over 2 trials: growing them together gave 1.17 times the harvest of two separate plots of the same size.

Partial LERs (medians): Tomato 0.68 + Cucumber 0.45. Range across treatments 0.92 to 1.42. Medians are taken separately, so the parts need not add up to the median LER. LER above 1 is biased upward by publication bias.

Yield trialfield trial x2

An experiment in intercropping cucumbers and tomatoes in Southern Michigan, U.S.A. (Schultz · 1982)

Effects of planting densities, irrigation, and hornworm larvae on yields in experimental intercrops of tomatoes and cucumbers (Schulz · 1987)

Tradition saysGood

1 gardening-lore entry, 1 without a specific citation. Lore is a starting point, not proof.

None of the 1 tradition entry cites a specific source.

Companion plants for both tomatoes and cucumbers

Plants that are good neighbours of each. Biggest harvest gain first; each cell links to the evidence for that pair.

Plant	With tomatoes	With cucumbers
Bean	18% more harvest from the same spaceField trial, 2 studies. Charts: recommend.Evidence for tomatoes and beans	14% more harvest from the same spaceField trial, 1 study. Charts: recommend.Evidence for cucumbers and beans
Onion	Better soil and nutrient uptake and bigger combined harvestMixed results on soil and nutrientsField trial, 7 studies. Charts: not listed.Evidence for tomatoes and onions	Helpful plant chemistry and bigger combined harvestField trial, 3 studies. Charts: recommend.Evidence for cucumbers and onions
Garlic	No trial foundNot tested. Charts: recommend.Evidence for tomatoes and garlic	Bigger combined harvest and better soil and nutrient uptakeChemicals that hold growth backField trial, 5 studies. Charts: recommend.Evidence for cucumbers and garlic
Celery	No trial foundNot tested. Charts: recommend.Evidence for tomatoes and celery	Fewer pestsField trial, 2 studies. Charts: recommend.Evidence for cucumbers and celery

Harvest from the same space compares a bed with both crops against the same area split into single-crop beds, counting the harvest of both crops (the land equivalent ratio in yield trials).

The evidence, with sources

ResearchGood2 entries

No effectnutrients / soilgreenhouse / pot trialauto-classified

The intercropping partner affects arbuscular mycorrhizal fungi and Fusarium oxysporum f. sp. lycopersici interactions in tomato.
The intercropping partner affects arbuscular mycorrhizal fungi and Fusarium oxysporum f. sp. lycopersici interactions in tomato (Hage-Ahmed · 2013 · Mycorrhiza)

Relevance 95% · effect confidence 56%
Goodtrap cropfield trialauto-classified

Cucumber helps Tomato
Effect of intercropping on tomato yellow leaf curt virus incidenceon tomato
Effect of intercropping on tomato yellow leaf curt virus incidenceon tomato (Yin Xiangui · 2002 · Xi nan nong ye xue bao = Southwest China journal of agricultural sciences)

Relevance 93% · effect confidence 57%

Yield trialGood2 entries

GoodLER 1.05field trial

USA, 1980; Additive design; median LER 1.06 over 16 treatment(s) · partial LER Cucumber 0.4, Tomato 0.585
An experiment in intercropping cucumbers and tomatoes in Southern Michigan, U.S.A. (Schultz · 1982)
GoodLER 1.28field trial

USA, 1981-1982; Additive design; median LER 1.28 over 6 treatment(s) · partial LER Cucumber 0.495, Tomato 0.775
Effects of planting densities, irrigation, and hornworm larvae on yields in experimental intercrops of tomatoes and cucumbers (Schulz · 1987)

TraditionGood1 entry

GoodCucumber helps Tomato
Tomatoes: helped by cucumbers
List of companion plants (uncited entry) (Wikipedia)

Plan a bed with tomatoes and cucumbers

All neighbours of tomato and of cucumber, or every pair at once in the companion planting chart.

Have you grown tomatoes and cucumbers together?

Tell other gardeners what happened: spacing, pests, harvest, or ask a question. Reader notes are not checked by us and do not change the verdicts on this page.