Plans from Bailey Design are for the 1,965 sqm floor space to be increased by an extra 1,533 sqm.
A report with the application submitted by owner Gerald Ingram said: "As with most garden centres now, outdoor plants, shrubs and trees only account for a small percentage of overall sales.
"There is a greater need for internal sales areas with emphasis on leisure, aquatics, clothing, foods and gifts. The sales and store extension will mirror the existing framed building. The proposals form the final plans to improve and develop the garden centre for future growth."