Sandyway Nurseries, a former tomato and bedding plant grower that owns the site near Newent, had enforcement notices served against its 23 caravans by Forest of Dean District Council.
These house more than 60 Romanian and Bulgarian nationals who mainly work at Haygrove Nurseries' adjacent glasshouses and polytunnels.
Sandyway owner Jacob van der Lely told Grower: "It's been in the planning process for nearly 10 years and perhaps for that reason they have now served an enforcement notice." But having appealed against these, he added that he is "hopeful of a favourable result soon".
Planning inspector Hilda Higenbottam has already supported retaining the caravans: "If this industry does not have suitable accommodation for seasonal workers the economy would suffer."