What Is Companion Planting?
Companion planting is the practice of growing certain plants together to create mutual benefits — whether that's deterring pests, attracting pollinators, improving soil, or simply making more efficient use of space. Herbs are some of the most useful companion plants in any garden, offering fragrant natural pest deterrents and flowers that draw beneficial insects.
How Herbs Help the Vegetable Garden
Herbs contribute to the garden in several practical ways:
- Pest deterrence: Strong-smelling herbs confuse and repel insects that locate host plants by scent.
- Attracting beneficial insects: Flowering herbs like dill, fennel, and coriander draw hoverflies and parasitic wasps that prey on garden pests.
- Pollinator support: Herbs allowed to flower provide valuable nectar for bees, improving fruit and vegetable yields.
- Ground coverage: Low-growing herbs like thyme can act as living mulch, suppressing weeds and retaining soil moisture.
The Best Herb Companions for Common Vegetables
Tomatoes
Best companions: Basil, parsley, borage
The classic pairing of basil and tomatoes isn't just culinary — many gardeners swear that basil planted nearby improves tomato flavour and deters aphids and whitefly. Borage repels tomato hornworm and attracts bees. Parsley planted at the base of tomato plants can deter certain soil-dwelling pests.
Brassicas (Cabbage, Broccoli, Kale)
Best companions: Dill, rosemary, mint (in containers), thyme
Brassicas are magnets for cabbage white butterflies and aphids. Dill attracts the predatory wasps that parasitise caterpillars. Rosemary and thyme help mask the scent of brassicas from egg-laying butterflies. Mint is a powerful deterrent but should be grown in pots near (not in) the bed to prevent it from spreading invasively.
Carrots
Best companions: Rosemary, sage, chives
Carrot fly is the main threat, and it locates carrots by scent. Interplanting with strongly aromatic herbs — particularly rosemary and sage — can help disrupt this. Chives are also said to improve carrot flavour when grown nearby, though the evidence is largely anecdotal and traditional.
Beans and Peas
Best companions: Summer savory, dill
Summer savory has a long traditional association with beans — it's sometimes called the "bean herb." It's said to improve the flavour of beans and deter black bean aphid. Dill attracts beneficial insects and works well interplanted with legumes.
Cucumbers and Courgettes
Best companions: Dill, nasturtium, oregano
Nasturtium acts as a trap crop, luring aphids away from cucumbers. Dill and oregano attract pollinators, which cucumbers and courgettes need for fruit set. Avoid planting fennel near cucumbers — it tends to inhibit the growth of many vegetables.
Herbs to Use Carefully
| Herb | Caution |
|---|---|
| Fennel | Allelopathic — inhibits growth of many neighbouring plants. Best grown in isolation. |
| Mint | Spreads aggressively via underground runners. Always grow in a buried pot. |
| Wormwood | Releases compounds that can inhibit nearby plants; best kept at garden borders. |
Getting Started with Herb Companions
You don't need to overhaul your garden to try companion planting. Start simply: tuck a few basil plants between your tomatoes, scatter some dill seeds near brassicas, and let a patch of chives flower at the edge of your beds. Observe what happens over the season, and build your companion planting strategy from there.