Onions & carrots: the onions help to keep the carrot root fly at bay, while the carrots do their bit by repelling the onion fly.

Celery & brassicas (the cabbage, cauliflower and broccoli family of plants): the celery will help to minimise, though not eliminate, damage caused by white butterfly larvae.

Marigolds & beans/brassicas: the marigolds emit a natural gas which protects surrounding plants from insects like aphids and white fly; in addition, the marigold’s root system attracts nematodes and disrupts their reproductive cycle.

Basil & tomatoes: Tomatoes are susceptible