Does Planting Basil Next to Tomatoes Really Help?

Basil and tomato is perhaps the most famous companion planting combination — and also one of the most debated. The claim that basil improves tomato flavour, repels pests, and promotes tomato growth has been repeated in gardening books for decades. The practical and culinary reality is that basil and tomatoes do thrive in the same conditions — both love warmth, full sun, and consistent moisture — and growing them together is practically convenient. Whether basil offers measurable pest protection is less clear-cut, but it does attract beneficial insects, and there is no harm in the combination.

What basil offers as a companion

Basil's strongly aromatic leaves contain volatile compounds that may confuse the host-location behaviour of some pests — aphids and thrips in particular. When basil is allowed to flower (rather than constantly pinched back), it produces small white blooms that are highly attractive to bees and hoverflies. These insects, once drawn into the area by the basil flowers, also visit tomato flowers and improve pollination. In enclosed spaces like greenhouses, the aromatic presence of basil is thought to help mask the tomato scent from some pests.

How to grow basil with tomatoes

Plant basil at the base of tomato plants — between rows or at the foot of individual plants. For greenhouse tomatoes, place a pot of basil between every two to three plants along the row. Allow some basil plants to flower rather than pinching every flower bud — this maximises the beneficial insect attraction. Basil and tomatoes share roughly the same watering and feeding requirements, so there is no conflict in managing them together. Both resent cold temperatures, so both should be kept protected from cold nights.

Other crops that benefit from basil

Beyond tomatoes, basil is said to be a useful companion for peppers and aubergines — all members of the Solanaceae family with similar growing requirements. It is also used near asparagus (reputed to deter asparagus beetle), and as a general herb garden companion. Basil is best kept away from sage, which is said to inhibit its growth when the two are planted closely.