Tesco and Aldi have joined Asda and Morrisons in rationing certain fresh produce lines as shortages of salad crops hit the UK. The UK’s biggest supermarket chain and the German-owned discounter announced on Wednesday that they were limiting purchases of peppers, cucumbers and tomatoes to three packs a person. Sainbury’s, Lidl and Waitrose said they still had no restrictions. The latest rationing announcement comes a day after rivals Asda and Morrisons announced limits on certain vegetable and fruit lines amid shortages caused by unusually cold weather in Europe and north Africa. Experts have said the problems could last for weeks. UK producers said supplies from British farms would also be hit as many have cut back planting amid the rising cost of heating greenhouses to grow salad crops. Morrisons put limits of two an item on packs of tomatoes, cucumbers, lettuce and peppers from Wednesday. Asda said on Tuesday it was limiting shoppers to three items each on eight fresh produce lines – including broccoli, cauliflower, raspberries and lettuces – to ensure all customers could get what they needed. Aldi said: “We are limiting purchases of peppers, cucumbers and tomatoes to three units per person to ensure that as many customers as possible can buy what they need.” Industry insiders have said availability of produce is down by between 30% and 40% on some crops, with the pepper harvest down 70% in Spain, according to the catering supplier Reynolds. Unusually cold weather has also affected crops in north Africa, which is often used as an alternative to Spain, while shipments by boat from Morocco have recently been affected by storms. The issue has been made worse after many retailers chose to rely more heavily on crops from southern Spain and north Africa this year because of the increased costs of energy to heat greenhouses in the UK and the Netherlands. Some importers say Brexit is also a factor, as the increased costs and paperwork involved in shipping to the UK have put it at the back of the queue for products in short supply. Wholesale prices have shot up to three times normal levels in some cases, adding to inflation in stores and leading to empty shelves. At this time of the year, Murcia in south-east Spain produces an estimated 80% of many salad and vegetable crops sold in the UK. Production in Britain does not usually begin until March. Italy, Morocco, Tunisia and Egypt are often used as alternative sources of supply in winter.