Supermarkets are warning shoppers that their pumpkins could be green-tinged, as the sector faced its second-worst harvest on record.

Asda has displayed signs that cautions customers, “Don’t worry if I’m slightly green, I will ripen at home and turn orange”, however the supermarket giant claims that despite their odd appearance, its supplies will not be affected.

Speaking to Grocery Gazette, a spokesperson for Asda said the supermarket is “not bracing for any shortages”, and had seen an increase in stock year-on-year, and now expects to sell around 1.8m pumpkins.

Yet the notices come amid a difficult year for pumpkin harvest, where farmers have said the wet weather in spring and slugs has impacted the quality of the yield.

Speaking to The Guardian, pumpkin supplier Barfoots’ chief executive Julian Marks said some of the year’s initial plantings had “failed”.

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Marks said: “When the weather improved the fields were replanted but some did not have enough time to turn orange. There is quite a lot of green out there.”

“Right from the start of the season the weather has been not conducive to a bountiful harvest. In terms of ripeness, they’re perfectly good pumpkins and they’ll carve and look wonderful in the dark with a candle stuck in the middle, but they might not be 100% orange.”

This year’s crops were also hit by slugs, with the National Trust gardeners claiming the pests are to blame for their decreased pumpkin haul.

British Growers Association chief executive Jack Ward added: “Pumpkins don’t like those conditions…slugs are a big problem too. It’s by no means universal. Some people have had a good run but I think the general feedback is that it has been a difficult season.”

Despite this, other supermarkets are reassuring shoppers of the availability of the crop for Halloween, with Morrisons and Tesco reporting they have not experienced any issues.