British onion supplies are set to tighten after extreme heat and prolonged drought severely hit this year’s crop, with growers warning of smaller bulbs, lower yields and quality issues.

The British Onion Producers’ Association (BOPA) said the 2026 season had been the most challenging ever faced by the industry, with East Anglia, where around 90 per cent of British onions are grown, particularly badly affected.

The region recorded just 2mm of rainfall during July, around 96 per cent below average, according to figures cited by the trade body.

Dry conditions have continued into August, putting further pressure on crops across eastern England.

Despite growers investing heavily in irrigation, BOPA said water shortages and restrictions had prevented some producers from irrigating crops at critical stages of development.

The conditions have caused onions to mature far earlier than usual, with some crops finishing more than a month ahead of schedule.

BOPA warned this had reduced plant populations, bulb sizes and marketable yields, while the prolonged heat was also creating concerns over crop quality.

Chairman Ben Collins said: “This is the most challenging season ever encountered by the British onion industry.

“The combination of prolonged drought, extreme heat and limited water availability has put this year’s crop under extreme pressure.

“It is clear that yield and bulb size will be a challenge this season, while the extreme growing conditions are also creating significant concerns around quality.”

The association said onions had endured temperatures of between 25°C and 35°C for much of the period alongside extremely low rainfall.

It warned the resulting heat stress could increase the risk of Fusarium, commonly known as base rot, adding another challenge for growers already facing sharply reduced yields.

BOPA expects the impact to translate into tighter supplies, smaller sizes and lower overall availability from the 2026 British crop.

The association added that similar weather conditions were also affecting onion production across Europe, where yields in some key growing regions are forecast to be more than 25% below normal.

The difficult season has also renewed calls for greater investment in water security.

BOPA said more support was needed to help growers invest in irrigation infrastructure and water storage, particularly in major food-producing regions such as East Anglia.

The trade body said British growers would continue working to maximise quality and availability but warned that the 2026 crop would be “substantially earlier and shorter in supply than normal”.

BOPA represents more than 80 per cent of the British onion industry, including growers, packers, processors, agronomists and other businesses across the supply chain.

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