Companion Planting: What Works and What Is Mostly Folklore

Owen Petrakis · Oct 15, 2026 · 4 min read

Quick answer

Some plant pairings genuinely help each other. Others are garden myths. Here is how to tell the difference.

Companion planting means growing different plants close together for mutual benefit. Some combinations have solid evidence behind them, while others are passed down with little more than tradition.

The practical approach is to use the well-supported pairings and treat the rest as an experiment.

Pairings with good support Mixed or uncertain evidence Practical tips

1 Pairings with good support

✓Flowers such as calendula, alyssum, and phacelia attract hoverflies and parasitic wasps that prey on aphids
✓Nasturtiums can act as a sacrificial crop, drawing aphids and caterpillars away from other plants
✓Tall crops such as sweetcorn can provide useful shade for lettuce in hot weather
✓Legumes such as beans and peas host bacteria that fix nitrogen, which can benefit following crops

2 Mixed or uncertain evidence

✓Basil improving tomato flavour is widely repeated but not well established
✓Marigolds deterring pests varies by marigold type and pest; some effects on soil nematodes have been observed with certain varieties
✓Strong-smelling herbs masking crops from pests may help a little, but rarely enough on their own

3 Practical tips

Plant a strip of flowering plants alongside vegetable beds. Mix crops rather than growing large blocks of one plant. Rotate crop families each year to reduce soil-borne diseases. Above all, keep a note of what you tried and what happened in your own garden.

This is general gardening information. Results depend on your climate, soil, and conditions. Follow label directions for any fertiliser or treatment, and check whether plants are toxic to pets or children before bringing them home.

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