Tradition
Good
avoidgood
2 chart entries: 2 recommend, 0 advise against.
All entries cite a source.
Leek
Allium ampeloprasum var. porrum
Amaryllidaceae
Tomato
Solanum lycopersicum
SolanaceaeCan you plant leeks and tomatoes together?
Yes. Leeks and tomatoes grow well together. Tomatoes had less disease next to leeks in a greenhouse or pot trial, and leeks improved the soil or nutrient uptake of tomatoes in a greenhouse or pot trial. That rests on two studies, so treat it as a lead, not a rule.
Why leeks and tomatoes work together
Less disease. In a greenhouse or pot trial, tomatoes had less disease next to leeks.
Growth and root-knot nematode infection of tomato are influenced by mycorrhizal fungi and earthworms in an intercropping cultivation system with leeks (Detrey J · 2021 · Applied Soil Ecology.)Better soil and nutrient uptake. In a greenhouse or pot trial, leeks improved the soil or nutrient uptake of tomatoes.
The intercropping partner affects arbuscular mycorrhizal fungi and Fusarium oxysporum f. sp. lycopersici interactions in tomato (Hage-Ahmed · 2013 · Mycorrhiza)Garden charts recommend it. 2 garden chart entries recommend growing them together. Charts pass on gardening tradition; they are not tests.
The intercropping partner affects arbuscular mycorrhizal fungi and Fusarium oxysporum f. sp. lycopersici interactions in tomato (Hage-Ahmed · 2013 · Mycorrhiza)
What to plant with leeks and tomatoes
Good neighbours of both, best tested first.
What to keep away from leeks and tomatoes
Swiss chardWith leeks: Garden charts advise against it, not tested
RosemaryWith tomatoes: 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
Research
Good
avoidgood
2 papers found: 2 positive, 0 negative.
disease suppressionnutrients / soil
auto-classified not reviewed by a person
Yield trial
No intercropping yield trial.
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.
Companion plants for both leeks and tomatoes
Plants that are good neighbours of each. Biggest harvest gain first; each cell links to the evidence for that pair.
| Plant | With leeks | With tomatoes |
|---|---|---|
 Cabbage | 16% more harvest from the same spaceField trial, 1 study. Charts: not listed.Evidence for leeks and cabbage | 34% more harvest from the same spaceField trial, 4 studies. Charts: not listed.Evidence for tomatoes and cabbage |
 Celery | Less competition19% more harvest from the same spaceField trial, 2 studies. Charts: recommend.Evidence for leeks and celery | No trial foundNot tested. Charts: recommend.Evidence for tomatoes and celery |
 Onion | No trial foundSame family (Amaryllidaceae): shares pests and diseasesNot tested. Charts: recommend.Evidence for leeks and onions | 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 |
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
- Gooddisease suppressiongreenhouse / pot trialauto-classifiedLeek helps TomatoGrowth and root-knot nematode infection of tomato are influenced by mycorrhizal fungi and earthworms in an intercropping cultivation system with leeksGrowth and root-knot nematode infection of tomato are influenced by mycorrhizal fungi and earthworms in an intercropping cultivation system with leeks (Detrey J · 2021 · Applied Soil Ecology.)Relevance 90% · effect confidence 75%
- Goodnutrients / soilgreenhouse / pot trialauto-classifiedLeek helps TomatoThe 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 97% · effect confidence 87%
- GoodLeek helps TomatoLeek: helps tomatoThe intercropping partner affects arbuscular mycorrhizal fungi and Fusarium oxysporum f. sp. lycopersici interactions in tomato (Hage-Ahmed · 2013 · Mycorrhiza)
- GoodLeek helps TomatoTomatoes: helped by leeksThe intercropping partner affects arbuscular mycorrhizal fungi and Fusarium oxysporum f. sp. lycopersici interactions in tomato (Hage-Ahmed · 2013 · Mycorrhiza)
All neighbours of leek and of tomato, or every pair at once in the companion planting chart.
Have you grown leeks and tomatoes 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.