Companion Planting Guide for UK Vegetable Gardens
Grow healthier, more productive vegetables by planting the right crops together. Companion planting is nature's way of pest control, pollination, and space optimization.
What is Companion Planting?
Companion planting is the practice of growing certain plants together for mutual benefit. Some plants help each other by repelling pests, attracting beneficial insects, improving soil, or providing physical support. Others compete for resources and should be kept apart.
Benefits of Companion Planting:
- Natural pest control: Some plants repel pests that attack their neighbors
- Attract beneficial insects: Flowers attract pollinators and predatory insects
- Maximize space: Tall and short crops can share the same bed
- Improve soil: Legumes fix nitrogen for heavy feeders
- Provide support: Sturdy plants can support climbing crops
- Shade sensitive crops: Tall plants protect heat-sensitive crops
Classic Companion Planting Combinations
The Three Sisters (Traditional Native American Method)
Sweetcorn + Climbing Beans + Squash
- Sweetcorn provides support for beans to climb
- Beans fix nitrogen in soil for corn and squash
- Squash leaves shade soil, suppress weeds, retain moisture
How to Grow Sweetcorn | How to Grow Beans | How to Grow Squash
Tomatoes + Basil
Basil repels aphids and whitefly from tomatoes, and many gardeners believe it improves tomato flavor.
Carrots + Onions
Onions repel carrot fly, while carrots repel onion fly. A perfect partnership!
How to Grow Carrots | How to Grow Onions
Lettuce + Radishes
Fast-growing radishes mark rows of slow-germinating lettuce and are harvested before lettuce needs the space.
How to Grow Lettuce | How to Grow Radishes
Brassicas + French Marigolds
Marigolds repel cabbage white butterflies and other brassica pests.
Companion Planting Chart
Tomatoes
Good companions: Basil, carrots, onions, parsley, marigolds, nasturtiums
Avoid: Brassicas (cabbage, kale), potatoes, fennel
Carrots
Good companions: Onions, leeks, rosemary, sage, peas, lettuce, radishes
Avoid: Dill, parsnips
Beans (Runner & French)
Good companions: Sweetcorn, squash, cucumbers, potatoes, carrots, brassicas
Avoid: Onions, garlic, fennel
Potatoes
Good companions: Beans, peas, brassicas, marigolds, nasturtiums
Avoid: Tomatoes, cucumbers, squash, sunflowers
Onions & Garlic
Good companions: Carrots, beets, lettuce, brassicas, tomatoes
Avoid: Beans, peas, asparagus
Brassicas (Cabbage, Kale, Brussels Sprouts)
Good companions: Onions, garlic, beets, celery, potatoes, beans, marigolds
Avoid: Tomatoes, peppers, strawberries
Cucumbers
Good companions: Beans, peas, radishes, sunflowers, marigolds
Avoid: Potatoes, aromatic herbs (sage, rosemary)
Lettuce
Good companions: Carrots, radishes, onions, brassicas, beans
Avoid: Parsley (competes for nutrients)
Peas
Good companions: Carrots, turnips, radishes, cucumbers, beans, potatoes
Avoid: Onions, garlic
Squash & Courgettes
Good companions: Sweetcorn, beans, peas, radishes, marigolds
Avoid: Potatoes
Beneficial Flowers for the Vegetable Garden
French Marigolds (Tagetes patula)
Repel aphids, whitefly, and cabbage white butterflies. Plant throughout the vegetable garden.
Nasturtiums
Act as a "trap crop" for aphids and cabbage white butterflies - they attack nasturtiums instead of your crops.
Calendula (Pot Marigold)
Attracts hoverflies whose larvae eat aphids. Edible flowers too!
Borage
Attracts bees for pollination. Excellent near squash, cucumbers, and beans.
Phacelia
Attracts beneficial insects and bees. Can be used as a green manure.
Herbs for Natural Pest Control
- Rosemary: Repels carrot fly, cabbage moths
- Sage: Repels cabbage moths, carrot fly
- Thyme: Repels cabbage worms, whitefly
- Mint: Repels aphids, flea beetles (but plant in pots - it's invasive!)
- Chives: Repel aphids, carrot fly
Planning Your Companion Planting
1. Start with Your Main Crops
Plan your main vegetables first using our UK Planting Calendar, then add companions around them.
2. Use Flowers as Borders
Plant marigolds, nasturtiums, and calendula around the edges of beds for all-season pest protection.
3. Interplant Fast & Slow Crops
Sow quick crops (radishes, lettuce) between slow-maturing crops (brassicas, parsnips) to maximize space.
4. Consider Height & Shade
Plant tall crops (sweetcorn, beans on poles) on the north side so they don't shade shorter crops.
5. Rotate Companions Too
Include companion plants in your crop rotation plan to prevent pest and disease buildup.
Tools for Companion Planting
- Garden markers: Label companion groups so you remember what's planted where
- Measuring tape: Ensure proper spacing between companions
- Garden planner: Sketch your companion planting layout before sowing
Download Our Garden Planner
Plan your companion planting layout with our free printable garden planner.
Build The Plan Into Your Garden
Planning guides are easier to act on when you pair them with bed records, soil preparation, and the right basic tools.
Plan the next step
Use the printable UK Vegetable Garden Planner to turn this guide into sowing dates, bed layouts, and weekly garden tasks.