Companion Planting Guide: Grow Better Vegetables Together
Learn which vegetables, herbs, and flowers grow best together. A complete companion planting chart and guide for European gardeners.
Spring is here, and if you're planning your vegetable beds, there's one technique that can make a real difference to your harvest: companion planting. By growing certain plants side by side, you can reduce pests, improve pollination, and make better use of limited garden space — all without any extra cost or effort.
In this guide, you'll learn which combinations work best, which plants to keep apart, and how to put it all into practice in your European garden.
What Is Companion Planting?
Companion planting is the practice of growing different plants close together so they benefit each other. Some plants repel pests that would otherwise attack their neighbours. Others attract pollinators or fix nitrogen in the soil, feeding the crops around them. A few simply make good use of space — like growing a fast-maturing lettuce in the shade of tall sweetcorn.
This isn't a new idea. European gardeners have been using mixed planting for centuries, from the traditional French potager to the Czech zahrádkářská kolonie. The principle is simple: diversity in the garden creates a healthier growing environment.
The Best Companion Planting Combinations
Here's a quick-reference chart of the most reliable pairings for European vegetable gardens:
| Vegetable | Good Companions | Why It Works |
|---|---|---|
| Tomatoes | Basil, carrots, parsley, marigolds | Basil repels aphids and whitefly; marigolds deter nematodes |
| Carrots | Onions, leeks, Rosemary, sage | Alliums mask carrot scent from carrot fly |
| Beans | Sweetcorn, squash, carrots | Beans fix nitrogen; the "three sisters" support each other |
| Cabbage family | Dill, celery, nasturtiums, thyme | Aromatic herbs confuse cabbage white butterflies |
| Courgettes | Nasturtiums, sweetcorn, beans | Nasturtiums act as a trap crop for aphids |
| Lettuce | Radishes, strawberries, chives | Radishes mature fast, freeing space; chives deter aphids |
| Potatoes | Horseradish, beans, marigolds | Horseradish repels potato beetle; beans add nitrogen |
Tomatoes and Their Best Companions
Tomatoes are the centrepiece of many European vegetable gardens, and they respond well to companion planting. Basil planted alongside tomatoes is one of the most widely recommended pairings — it repels aphids and may even improve the flavour of nearby fruit. Carrots and parsley thrive in the partial shade beneath tomato plants, making good use of vertical space.
French marigolds (Tagetes patula) are another excellent partner. Their roots release compounds that suppress soil nematodes, and their bright flowers attract hoverflies, which eat aphids by the hundreds.
Brassicas and Protective Neighbours
Cabbages, broccoli, kale, and cauliflower are magnets for pests — especially the cabbage white butterfly. Planting aromatic herbs like dill, thyme, and sage nearby can confuse these pests by masking the scent of brassica leaves.
Nasturtiums serve as a "trap crop" for cabbage caterpillars and aphids. The pests are drawn to the nasturtiums instead, sparing your brassicas. Celery is another useful neighbour, as its strong scent helps deter cabbage moth.
Root Vegetables and Complementary Partners
Carrots and onions are a classic European pairing. Onion scent masks the carrot from carrot root fly, while the carrot's foliage helps shade the onion's shallow roots. Leeks and carrots work the same way and are a staple of traditional French kitchen gardens.
Beetroot pairs well with lettuce and brassicas, and garlic makes a strong companion for almost anything — its sulphur compounds deter a wide range of pests.
Herbs and Flowers That Protect Your Garden
Beyond vegetables, herbs and flowers play a crucial role in companion planting.
Must-Have Herbs for Your Beds
- Basil — repels aphids, whitefly, and mosquitoes. Excellent near tomatoes and peppers.
- Dill — attracts beneficial insects like ladybirds and lacewings. Great near brassicas.
- Chives — deter aphids and carrot fly. Plant along bed edges.
- Sage — repels cabbage moth and carrot fly. Thrives in sunny European gardens.
- Rosemary — deters bean beetles, cabbage moth, and carrot fly. A Mediterranean herb at home in warmer European climates.
Flowers for Natural Pest Control
- French marigolds (Tagetes patula) — the single best companion flower. They repel whitefly, attract hoverflies, and suppress root nematodes.
- Nasturtiums — a sacrificial trap crop for aphids and cabbage caterpillars. Easy to grow, edible, and beautiful.
- Calendula (pot marigold) — attracts pollinators and predatory insects. A traditional cottage garden staple.
- Borage — a magnet for bees and an excellent companion for strawberries and tomatoes.
Plants to Keep Apart
Not all neighbours get along. Some plants compete for nutrients, stunt each other's growth, or attract shared pests.
| Keep Apart | Reason |
|---|---|
| Tomatoes + fennel | Fennel releases substances that inhibit tomato growth |
| Beans + onions/garlic | Alliums stunt bean growth |
| Potatoes + tomatoes | Both are nightshades — shared blight risk |
| Carrots + dill | Dill can cross-pollinate with carrots, affecting seed quality |
| Cabbage + strawberries | Compete heavily for nutrients |
Quick Rule of Thumb
Avoid planting members of the same family close together — they share pests and diseases. Rotate families across your beds each year for the healthiest results.
How to Plan a Companion Planting Bed
Putting companion planting into practice is easier than it looks. Start with your main crops — the vegetables you want to harvest — and then fill the gaps with companion herbs and flowers.
- Choose your main crops. Decide what you want to grow this season. Tomatoes, courgettes, beans, and salad greens are popular spring starters for what to plant in March.
- Check the chart. Look up each crop's best companions and note which plants to avoid placing nearby.
- Group by need. Plants with similar water and sunlight needs should share a bed. Mediterranean herbs like sage and Rosemary prefer drier soil than water-hungry brassicas.
- Add flowers at the edges. Border your beds with marigolds, nasturtiums, or calendula to create a natural pest barrier.
- Use vertical space. Tall crops like sweetcorn or runner beans can shade lettuce or spinach below.
Planning Tip
Use Plantory's garden planner to drag and drop crops onto your bed layout. The planner highlights companion relationships, so you can spot good — and bad — neighbours at a glance.
Common Mistakes to Avoid
- Overcrowding. Companion planting isn't an excuse to cram plants together. Every crop still needs its recommended spacing for light and airflow.
- Ignoring crop rotation. Even the best companions can't overcome soil exhaustion. Rotate plant families across your beds each year.
- Forgetting regional timing. In Atlantic climates (Cfb), you can plant companions earlier than in continental zones (Dfb). Check your local climate zone before planning.
- Planting fennel in the vegetable bed. Fennel inhibits most vegetables — give it its own spot, well away from the main beds.
- Relying solely on companions. Companion planting is a bonus, not a substitute for good soil, watering, and sunlight.
Summary
Companion planting is one of the simplest ways to grow healthier, more productive vegetables. By pairing crops that naturally support each other — and keeping enemies apart — you can reduce pests, attract pollinators, and make the most of every square metre in your garden.
Start small: pick two or three pairings from the chart above, plan your beds, and see the results for yourself this season.