Companion plants are like friends – they’re there to support you. In addition, companion plants deter pests and provide nutrients to the soil, keeping the surrounding plants healthy.The best companion plants for potatoes include culinary herbs like chives, thyme, and basil, vegetables like onion, beans, celery, and corn, and flowers like nasturtium and marigold. Avoid planting potatoes nearby brassicas, carrots, and squash.