Tomato Companion Plants: Best Partners (and What to Avoid)
The best tomato companion plants for European gardens – plus the crops to keep well away. A practical list of what to grow with tomatoes.
Tomatoes are the star of most European vegetable gardens, but they rarely do their best alone. The right neighbours can repel the pests that plague them, pull in pollinators, and make good use of the bare soil around each plant. The wrong neighbours can stunt growth or spread disease.
This list covers the seven best tomato companion plants for European gardens, explains exactly why each one earns its place, and finishes with the crops you should keep well away. Midsummer is the perfect time to slot companions into gaps around your maturing tomato plants.
1. Basil: The Classic Tomato Partner
Basil is the most famous of all tomato companion plants, and the pairing works in the kitchen as well as the bed. Its strong scent helps mask tomatoes from aphids and whitefly, and many gardeners are convinced it improves the flavour of nearby fruit.
Plant basil 25 to 30 cm from the base of each tomato. It enjoys the same warm, sunny conditions and appreciates the light shade the taller tomato foliage casts during the hottest part of a Mediterranean summer.
2. French Marigolds: Pest Control in a Flower
French marigolds (Tagetes patula) are arguably the single most useful flower you can grow near tomatoes. Their roots release compounds that suppress soil-dwelling nematodes, and their bright blooms draw in hoverflies, whose larvae eat aphids by the hundreds.
Dot a few marigolds through the tomato bed or line the edges. They flower all summer, ask for very little, and self-seed happily for next year.
3. Nasturtiums: A Sacrificial Trap Crop
Nasturtiums work as a trap crop: aphids and whitefly are drawn to them and settle there instead of on your tomatoes. When the pests gather, you can simply remove the worst-affected leaves.
They also sprawl attractively along the ground, shading the soil and keeping roots cool. Both leaves and flowers are edible with a peppery bite, so they earn a second place at the table too.
4. Carrots and Parsley: Filling the Space Below
Tomatoes are tall and leave plenty of open ground beneath them. Carrots and parsley thrive in that partial shade, making use of space that would otherwise sit empty. Parsley also attracts hoverflies and parasitic wasps that prey on tomato pests.
Sow carrots and parsley while your tomato plants are still small, so they establish before the canopy closes over.
5. Borage: A Magnet for Bees
Borage is one of the best pollinator plants you can grow. Its blue star-shaped flowers are covered in bees from morning to dusk, and better pollination means more fruit set on your tomatoes. Some gardeners also credit it with deterring the tomato hornworm.
It grows fast and can get large, so give it a corner where it will not crowd the crop. Like nasturtium, its flowers are edible and make a pretty addition to summer salads.
6. Chives and Other Alliums: Aphid Deterrents
Chives, garlic, and onions all carry sulphur compounds that discourage aphids and other soft-bodied pests. Chives in particular make a tidy edging plant around a tomato bed and produce edible flowers that pollinators love.
Keep alliums to the margins rather than tucking them right up against the stems, and they will earn their keep all season.
7. Lettuce and Salad Leaves: A Living Mulch
Fast-growing lettuce and other cut-and-come-again leaves fill the ground around young tomato plants, shading the soil and reducing water loss. They mature and are harvested long before the tomatoes reach full size, so there is no lasting competition.
This is a classic way to get two harvests from one patch of ground – a real advantage in a small European garden or on an allotment.
Plants to Avoid Near Tomatoes
Not every neighbour is a good one. Keep these crops well away from your tomato bed:
| Keep Away | Reason |
|---|---|
| Fennel | Releases substances that inhibit tomato growth |
| Potatoes | Both are nightshades and share blight risk |
| Brassicas (cabbage, kale, broccoli) | Heavy feeders that compete for nutrients |
| Sweetcorn | Attracts the corn earworm, which also attacks tomatoes |
| Walnut trees | Release juglone, which is toxic to tomatoes |
Quick Rule of Thumb
Never plant tomatoes next to another nightshade such as potatoes or aubergines – they share the same pests and diseases. Rotate the whole family to a fresh bed each year.
Quick Reference Table
| Companion | Main Benefit | Best For |
|---|---|---|
| Basil | Repels aphids and whitefly | Every tomato bed |
| French marigolds | Suppress nematodes, attract hoverflies | Edges and gaps |
| Nasturtiums | Trap crop for aphids | Sprawling ground cover |
| Carrots & parsley | Fill shaded space below | Small gardens |
| Borage | Attracts bees, boosts fruit set | Corners |
| Chives & alliums | Deter aphids | Bed edging |
| Lettuce | Living mulch, second harvest | Early season |
How to Plan a Tomato Bed with Companions
Start with your tomato plants at their proper spacing – usually 45 to 60 cm apart – then fill in around them:
- Anchor with basil. Tuck one or two basil plants between each pair of tomatoes.
- Ring the edges with flowers. Marigolds, nasturtiums, and borage along the borders form a natural pest barrier.
- Use the shade below. Sow carrots, parsley, or lettuce beneath the young plants before the canopy fills in.
- Keep the troublemakers out. No fennel, potatoes, or brassicas in the same bed.
For the full picture of which crops pair across your whole plot, see our companion planting guide. And if you are still getting your tomatoes established this season, our guide on how to grow tomatoes in Europe covers varieties, timing, and care for every region.
Choosing the right tomato companion plants is one of the easiest ways to grow a healthier, heavier crop. Pick two or three partners from this list, keep the troublemakers at a distance, and let your tomatoes get on with the job.