Clive Whitehouse, the inspector appointed by the Secretary of State for Communities and Local Government to consider the appeal over Pennoxstone Court, said: "Each block of polytunnels at Pennoxstone Farm, by virtue of its size, degree of permanence and physical attachment to the ground amounts to a building.
"The polytunnels subject to the enforcement notice amount to development for which planning permission is required," he added.
In his decision on the appeal, the inspector allowed part of the site to be used for polytunnels but he dismissed the appeal on the majority of the site.
The inspector also upheld the enforcement notice but ruled that the period of compliance should be extended until December 31, 2008.
Councillor John Jarvis, Herefordshire Council's cabinet member for environment and strategic housing, said: "The inspector has given us clear guidance on polytunnels which has come at an opportune time.
"Our officers are currently dealing with one polytunnel application and are in negotiation on a further five sites.
"In addition, our development control manager has been meeting a succession of growers over the past few weeks to discuss what they need to submit with their planning applications to have a reasonable chance of success," he added.
Herefordshire Council is also currently consulting over a supplementary planning document to cover polytunnel development and a draft document is likely to go to the council's planning committee in February.