RHS tells gardeners: stop growing cauliflower as heatwaves and drought bite

The claim

Society (RHS) is advising gardeners in England to stop growing cauliflower and rethink planting other brassicas because recent heatwaves and drought are making these crops unrewarding.

Why cauliflower is failing

Cauliflowers and close relatives such as calabrese are thirsty and sensitive to high temperatures. Under extreme heat they often bolt or fail to form a good head, and they need a lot of water and cool conditions to do well. RHS horticulturalists say many of their own gardens have already stopped growing cauliflower because results have been "hit and miss."

This advice comes after a summer that the Met Office provisionally recorded as the UK's hottest on record. Temperatures peaked at 38.1C (100.1F) at Kew Gardens on 13 August, and June was confirmed as the country's hottest June since records began in 1884.

What gardeners are planting instead

RHS staff report clear shifts in what grows well in current conditions. Popular and productive replacements include:

• Tomatoes and peppers — have thrived outdoors where watering can be maintained.
• Okra and loofah — have performed strongly in gardens and glasshouses.
• Sweet potatoes and cucumbers — successful outdoors in some areas.
• Kale — some varieties are perennial with deeper roots and better drought resilience.
• Purple sprouting broccoli — works as a cut-and-come-again crop rather than waiting for a single head.
• Yard-long beans, aubergines, chillies and Italian heirloom cucumber-melons have also produced very good crops in heat this year.

RHS horticulturists at Bridgewater, Wisley and Hyde Hall describe practical trial-and-error: Simone Bratt said cauliflowers bolted in spring sowings and were only grown as late crops previously. Liz Mooney reported focusing on warmth-loving crops and not growing cauliflower this year. Cat Hood listed strong yields of chillies, peppers, loofah and okra in outdoor beds and glasshouses.

Practical takeaways for gardeners

• If you rely on minimal watering or expect hot spells, avoid planting cauliflower and other brassicas that need cool, moist conditions.
• Prioritise crops with deeper roots or lower water demand (some kales, sweet potato) or clearly heat-adapted species (tomato, pepper, okra, loofah).
• Use cut-and-come-again strategies (for example, purple sprouting broccoli) rather than single-harvest heads to spread risk.
• Trial small plantings of Mediterranean or tropical vegetables to see what performs in your microclimate before committing larger beds.

What this means for the garden calendar

Gardeners will need to rethink veg-plot planning around recurring summer heat and drought. Replacing thirsty, cool-season brassicas with heat-tolerant crops reduces watering demands and increases the chance of a usable harvest in hotter summers.