Companion planting is the old gardener's art of growing certain plants together so they help each other — deterring pests, attracting helpful insects, making better use of space, and even improving flavour. It is not magic, and not every pairing is backed by hard science, but a thoughtful mix of crops and flowers genuinely makes for a healthier, more productive and more beautiful garden. Here is how to put it to work, whatever the size of your plot.
- Deter pests confuse and repel them
- Pollinators more bees, better crops
- Predators ladybirds eat aphids
- Save space grow more in less
What it is — and what to expect
At its simplest, companion planting means choosing plants that grow better next to each other than apart, and avoiding combinations that hold each other back. Some pairings are backed by solid research, others are generations of garden lore — so treat it as a helpful nudge rather than a guarantee. The single biggest benefit is diversity itself: a mixed, busy bed attracts more wildlife, suffers fewer pest outbreaks, and makes fuller use of light, space and soil than a bare block of one crop.
How it actually works
Several simple mechanisms are at play. Strongly scented plants mask or confuse pests that hunt by smell. Flowers attract pollinators and predators — bees to set your fruit, ladybirds and hoverflies to eat aphids. Trap crops lure pests away from your harvest and onto a sacrificial plant. Tall plants offer shade and shelter to tender neighbours, sprawling plants act as a living mulch that shades out weeds, and legumes such as beans and peas fix nitrogen that feeds the plants around them. Combine a few of these and the whole bed simply works better.
Classic good pairings
- Tomatoes + basil + marigolds — the herbs and flowers deter pests and draw in pollinators.
- Carrots + onions or leeks — their scents mask each other from carrot and onion fly.
- The Three Sisters: beans + corn + squash — beans climb the corn, squash shades the soil, beans feed both.
- Brassicas + aromatic herbs — dill, mint and sage help confuse cabbage pests.
- Cucumbers + dill + nasturtiums — dill draws predators, nasturtiums lure aphids away.
- Lettuce under taller crops — light summer shade stops it bolting.
- Strawberries + borage — borage brings bees and is said to improve the crop.
- Roses + garlic or chives — alliums help keep aphids off the roses.
Flowers and herbs that earn their place
A few hard-working plants belong in every vegetable patch:
- Marigolds — deter many pests and pull in hoverflies whose larvae devour aphids.
- Nasturtiums — a sacrificial trap crop that aphids and caterpillars flock to instead of your veg.
- Calendula — attracts pollinators and predators, and the petals are edible too.
- Borage — a magnet for bees that also partners well with strawberries.
- Alliums such as chives and garlic — their scent deters a range of pests.
- Aromatic herbs like basil, dill and coriander — they confuse pests and, once flowering, feed beneficial insects.
What to keep apart
- Onions, garlic and chives near beans and peas — they can check each other's growth.
- Fennel near almost everything — it inhibits many neighbours, so give it its own corner.
- Potatoes near tomatoes — both suffer blight, so keep them well apart.
- Hungry, spreading crops crowded together — brassicas and squashes need room, not competition.
How to use it in any garden
You do not need a big plot. Edge beds and paths with flowers, slip herbs between your rows, pop a marigold into every other module, and underplant tall crops with low ones. Even a few flowers dotted among your vegetables in pots will pull in pollinators and predators. The aim is diversity — a mixed, busy bed is a resilient one.
Keep it realistic
Think of companion planting as one helpful tool among many, working alongside good soil, sensible watering and basic pest control. Some pairings are well proven, others are garden lore — so experiment, keep what works in your garden, and enjoy the more colourful, livelier plot it creates along the way.
Frequently asked questions
Does companion planting really work?
Some pairings are well proven and others are traditional lore — but the diversity it brings genuinely helps, whichever the case.
What are the best companions for beginners?
Marigolds and basil with tomatoes, and borage with strawberries, are easy, rewarding places to start.
Can I companion plant in pots?
Yes — a flower and a crop in the same large pot works well on a patio or balcony.
Will it replace pest control?
No — it supports your other methods rather than replacing them.
Plant good neighbours, then browse all seeds.
