Owners of Grove Nurseries wanted to incorporate a Post Office into the redesign, but planning officers recommended the application be refused.
The owners wanted a change of use from nursery/market garden to garden centre, with erection of a single-storey link building.
But planners said: "The proposed development of the garden centre as proposed, with the majority of the site area for sales of items not produced on site, would result in an expansion of retail uses into open countryside, outside the settlement boundary for Lower Langford, where such uses are strictly controlled."
Meanwhile, Redfields Garden Centre in Fleet, Hampshire, has won permission for a cosmetic redevelopment, which will create six new jobs at the 120-staff, £5m annual turnover centre. Work will include new car parking, a cycleway, improved landscaping, better accessibility and better cycle parking. The centre will remain open while the work is done.