Branded salad supplier Florette has had a bumper summer, with sales rocketing by 24% year on year, the company says.

Record temperatures in July helped it on its way to £6.1m sales growth so far this year, boosting brand awareness from 64% in March to 70% four months later. MD Mark Newton said: "Growth is now more than 20% in a market showing 2% overall growth."

But many growers have reported problems maintaining quality and availability, particularly for iceberg lettuces and, to a lesser extent, little gem. Tighter supplies have kept prices above the seasonal average, with a class one iceberg selling for 64p at Asda, Tesco and Sainsbury's this week.

Peter Sargeant, leafy salads director for leading East Anglian grower G's, said keeping pace with high demand was proving a real challenge.

"Sales have been very strong this summer due to the warm weather, and availability of product has just about matched this," he said.

"There is traditionally a fall in demand at this time of year and a drop in price to counteract that, but we haven't seen a price fall this year and I think we will see market price strengthen and stay that way for a few weeks," he added.

He blamed the tight supply situation on the heat, which has created misshapen lettuces, internal breakdown and bolting plants.

"Iceberg lettuce has certainly been affected by fluctuations in quality, and ordinary lettuce to a certain extent, with little gem affected to a lesser degree."

British Leafy Salads Association chairman David Piccaver said: "It has been tricky to manage the gap in the planting and harvesting cycle but I don't expect any major shortages. However, there have certainly been improvements in retail prices."