Fruit and vegetable growers who sell through farmer’s markets, farm stands and community supported agriculture know that work associated with being a successful market grower does not end with the active growing season. The colder months are an ideal time to launch projects to improve efficiency, product quality and economic return for the season ahead. One viable project that can accomplish all three of these goals is the construction of a cold storage room.
Market growers typically sell their produce within a few days of when it was picked. Freshness of the product and its “localness” are factors that allow the grower to charge and collect premium prices. This makes quality essential for building customer loyalty and increasing sales. These farms generally are small to medium enterprises with local emphasis that do not operate with a broad financial base. The high cost for commercial or industrial-grade cooling equipment may be difficult to justify. The solution is lower-cost cold storage options that decrease inventory loss and increase sales by helping preserve produce freshness and quality for an additional few days.
An economical cold storage room can be built with off-the-shelf building materials using standard stud-wall construction techniques, provided it has sufficient insulation in the walls, floor, and ceiling. A vapor barrier to the warm side is needed, so for a cold room this means proper sealing to the outside of walls, floor, and ceiling. Insulated panels, like those used for garage doors, are another potentially economical construction material, depending on their availability as scrap or surplus. A standard room air conditioner can provide a low-cost cooling source. However, if you try to use a room air conditioner to cool below about 65˚F, the cooling coils will freeze up. This limitation can be overcome by outfitting the air conditioner with strip heaters, a thermostat, and a timer to create a defrost cycle that alternates power between the strip heaters and the compressor. At least one manufacturer now offers an off-the-shelf control unit that does the same thing.
To learn more about construction of a cold storage room to extend freshness and quality of fruits and vegetables, contact your local Cooperative Extension Service.
Submitted by John Wilhoit, Biosystems and Agricultural Engineering, University of Kentucky