Up to 200 workers have been told to self-isolate on the farm where they pick crops after 73 of them tested positive for Covid-19.
Vegetable producers A S Green and Co, in Herefordshire, has gone into lockdown after the positive tests.
Food and other essential supplies are being delivered to the farm, where the workers have been segregated into the mobile homes they live in. Herefordshire Council, which has organised the supply of deliveries, believes the outbreak is "contained" on the farm.
The firm is being supported by Public Health England (PHE).
A spokesman for the company said the welfare of its staff was its "priority" and further testing of management and visitors to the farm had so far produced negative test results.
As a precaution, the workers are being treated as "one extended bubble" and are staying within household groups, the council said.