Companion planting – combining plants for the benefit of one or both of the companions – is an age-old gardening tradition.
Companion plants can help to control pests by confusing them or by attracting predators. They can also act as sacrificial plants, luring pests away from a precious crop. They can also help each other by giving support, or by adding nutrients to the soil.
Discover 10 companion plants to grow, recommended by herb expert Jekka McVicar.
Though evidence for the benefits of companion planting is largely anecdotal, many combinations make good sense and can help to maximise use your space. It looks attractive, too.
Tuck the right flowers, herbs and other edibles around your veg in the garden or in containers for a great display, healthy plants and bumper harvests.
Tomatoes with tagetes
French marigolds (Tagetes patula) give off a distinctive smell that whitefly hate – so planting them under tomatoes, especially in the greenhouse, helps keep this pest at bay. Buy as inexpensive plugs and pop into borders, pots or growing bags between plants, 10cm apart.
Dwarf French beans with kale
Kales and cabbages thrive on the extra nitrogen beans draw into the soil from the air; in return, they provide sturdy, natural support. Sow kale three weeks before the beans, then sow a row of beans alongside them, 45cm-60cm apart. This combination does well in a raised bed or roomy container.
Carrots with leeks
Carrot flies can zero in on a crop from a mile away with one sniff of crushed foliage, so growing pungent alliums, such as leeks, acts as a protective barrier. The distinctive scent of carrots confuses onion fly and leek moth, too. Sow plenty of each in a patchwork or thick strips, and resow regularly.
Brussels sprouts with nasturtiums
Nasturtiums can swamp low-growing crops but they’re ideal companions for taller plants. They cover bare ground and lure aphids away from brassicas onto themselves. Sow direct or into modules, but wait until your Brussels reach 30cm high before planting them underneath, 25cm apart.
Broad beans with borage
Many claims are made about borage – it’s believed to make strawberries grow better and repel a host of pests. What is certain is that the flowers are magnets for pollinating insects, including hoverflies, whose larvae feast on blackfly on broad beans.
Fruiting veg with annual flowers
Annuals lure insects to pollinate fruiting plants, from squash and beans to tomatoes. They also attract predators to keep pests down. In autumn, sow annuals like pot marigolds (Calendula officinalis) to overwinter, so they’ll flower in time for early summer crops.
Climbing beans with lettuce
A canopy of climbing beans is ideal for shade-loving lettuces. Lettuce set 15cm apart covers bare ground in return for a feed, as beans add nitrogen to the soil. Young lettuce beside direct-sown beans also lures slugs away, leaving bean seedlings alone.
Plant companion plants at the same time as your crops so that pests do not have a chance to establish.
Other companion planting combinations to try
- Tomatoes with basil or pots of mint
- Dwarf beans with tomatoes or sweetcorn
- Carrots with spring onions, garlic or chives
- Nasturtiums with cabbage, kale or sweetcorn
- Broad beans with summer savory, or cabbage with sage.
- Tomatoes with calendula and runner beans with sweet peas
- Lettuce or chard with peas, kale or sprouts