How to Grow Cauliflower

Beetroot and cauliflower occupy different soil layers — beetroot's deep taproot draws minerals from lower horizons while cauliflower's shallower roots stay near the surface, so the two rarely compete. Their differing nutrient demands (cauliflower is a heavy feeder; beetroot is moderate) make them efficient bed-mates.

Onions emit sulphurous volatile compounds that confuse and deter cabbage white butterflies and aphids searching for brassica host plants by smell. Interplanting one row of onions for every two rows of cauliflower provides good coverage.

Rosemary's dense essential oils — primarily camphor and 1,8-cineole — mask the host-finding odours of cauliflower, reducing egg-laying by cabbage moths (Mamestra brassicae) and cabbage white butterflies. Plant rosemary on the windward side so volatile oils drift across the brassica bed.

Sage releases thujone and camphor-based volatiles that interfere with the olfactory navigation of cabbage moths and imported cabbageworm butterflies, reducing larval damage on cauliflower heads. A border of three or four sage plants per 2 m of row is sufficient.

Nasturtiums act as a trap crop: aphids — especially Myzus persicae — preferentially colonise the glucosinolate-rich nasturtium foliage over the cauliflower, concentrating pests where they can be removed or tolerated. Position nasturtiums at the bed edges so aphid colonies remain visible and easy to pinch off.

Solanine-related compounds in tomato root exudates inhibit the germination and early growth of brassica roots, while cauliflower's sulphur volatiles can suppress tomato fruit set. Keep them at least 60 cm apart and avoid following one with the other in crop rotation.

Strawberries release phenolic root exudates that suppress the uptake of boron and calcium in brassica roots — nutrients critical for cauliflower curd development. Conversely, cauliflower's heavy feeding depletes the potassium strawberries need for fruit sweetness; separate by at least 50 cm.