Tesco has restricted customers to three iceberg lettuces per shopping trip as the European vegetable shortage takes hold.
The retail giant is one of a number of supermarkets that have been forced to take the action, while sweet gem and romaine salad varieties have been taken off sale completely in some cases online.
An extreme mix of drought followed by flooding and freezing conditions has severely affected growers in southern Spain, while poor conditions have also hit farmers in Italy, Greece and Turkey.
Experts have warned that if the weather does not improve in the coming weeks the problem may continue until April, with customers hit by price rises.
The lettuce shortage follows similar reductions in the supply of courgettes, while salad peppers, broccoli and cabbage supplies are also under pressure.
Concerned healthy eaters have been sharing pictures of bare supermarket shelves with the hashtags #lettucecrisis and #courgettecrisis, while complaining that prices have nearly tripled in recent weeks.
Spain usually supplies half the vegetables on the European market during winter.
However, supermarkets have been forced to look as far afield as the US west coast to meet demand.
London retail analyst Rob Gregory posted a photo on Twitter of empty boxes in a Tesco and a sign that read: ‘Due to continued weather problems in Spain, there is a shortage on Iceberg and other varied lettuce products.
‘To protect the availability for all customers, we are limiting bulk purchases to three per person.”
He tweeted: ‘My local Tesco also affected by the lettuce and salad rationing. Not much there to ration though!’