What Are the Best Companion Plants for Beans?

Beans — whether runner, French, climbing, dwarf, or broad — are among the most useful plants to work with in a companion planting system. As legumes they fix nitrogen from the atmosphere into the soil via their root nodules, which means neighbouring plants often benefit from their presence. They also need pollinators to set pods, and they attract a range of pests that companions can help manage. Getting the planting right maximises all of these interactions.

Carrots and Beets — Classic Companions for Dwarf Beans

Dwarf French beans and carrots are traditionally grown together with good results. The beans fix nitrogen near the surface and their root architecture differs completely from the deep taproot of the carrot, so there is no competition. Carrots' feathery foliage can actually reduce the bean beetle's ability to locate host plants by visual cues. Beetroot also works well — it benefits from the trace amounts of nitrogen released near bean roots, and its leafy growth provides some shade that keeps the soil around beans moist in dry spells.

Summer Savory for Flavour and Pest Control

Summer savory is one of the most traditional companions for beans in European kitchen gardens and for good reason. Its strong scent appears to repel black bean aphids, which are a major problem on broad beans and climbing French beans alike. Summer savory also attracts bees, which improves pollination and therefore pod set. Sow it directly between bean plants or in dense patches at the ends of the row. It grows quickly from seed and can be used in the kitchen at the same time — a genuinely dual-purpose plant.

Nasturtiums as a Trap Crop for Black Aphids

Broad beans are particularly vulnerable to black bean aphid, which colonises the soft growing tips and can stunt plants if left unchecked. Nasturtiums planted at the edges of the broad bean bed act as a sacrificial trap crop — the aphids prefer them and concentrate on the nasturtium stems, sparing the beans. Plant nasturtiums two weeks before your broad beans go in so they are established and attractive before the aphid flight season begins.

Corn — the Three Sisters Partner

In the Three Sisters system, climbing beans grow up corn stalks while squash covers the ground below. The beans fix nitrogen that benefits both the corn and the squash, the corn provides a climbing structure, and the squash leaves reduce weed competition and moisture loss. This is one of the best-documented polyculture systems in the world. For it to work you need to plant the corn first so the stalks are strong enough to support the beans, then add beans two weeks later, and squash a week after that.

What to Keep Away from Beans

Onions, garlic, and other alliums are widely listed as bad companions for beans, and there is reasonable evidence that their root exudates can inhibit the symbiotic bacteria that allow beans to fix nitrogen — which undermines the main benefit of growing beans. Keep alliums in a separate bed. Fennel should be avoided near all vegetables. Beets are compatible with dwarf beans but not with climbing beans, where they tend to compete more aggressively for light and moisture.