BROOKSVILLE — Even in Florida, growing vegetables is a seasonal pursuit. But JG Ranch is stretching the payoff harvest season with a protected culture system known as high-tunnel production.
The 16-foot-high Quonset-shaped structures — opaque plastic sheeting stretched over metal frames — at first appear to be economy greenhouses. But there are several differences.
The huge expanse of plastic provides a greater surface area to capture more of the winter sun's heat, negating the need for artificial heat. Sides can be rolled up like window blinds to allow the release of summer heat. The manual temperature management means no surface irrigation is needed to ward off frost. And, less irrigation is necessary during the summer because the tunnel ceiling minimizes moisture evaporation.
Widely used in other countries, the system only recently has been adapted to Florida's climate through research at the University of Florida, and also has been validated by Hernando County Cooperative Extension Service director Stacey Strickland.
Strickland, who has a doctorate in plant science, is monitoring and has written several scientific papers on the system at JG Ranch, owned by the Joan and George Casey family, southwest of Brooksville.
UF research has revealed early high-tunnel yields that are 54 percent higher than in open fields, 16 percent higher in the second season.
Jeff Casey, 43, who is in charge of the family's five-tunnel installation, couldn't be more pleased with the results. The extended harvest season has allowed for year-round sales at the family's onsite part-time farm market.
On a recent chilly, blustery day, Casey invited visitors into a warm tunnel and noted: "No heaters! It's 8 degrees warmer inside than outside. I can add 10 degrees (more) with freeze covers."
The latter are, essentially, blankets of baby diapers laid over plant-high hoops, appropriate for low-growing plants such as peppers, which Casey is currently harvesting for off-season prices. He figures the crop will produce for four months.
On space-saving trellises, Casey is picking cucumbers, another high-profit vegetable at this time of year.
Vining tomatoes are just coming into harvest.
"They'll keep growing and producing until you kill them," Strickland said.
Casey figures his tomato harvest season now covers 20 weeks of the year.
Joan Casey, Jeff Casey's mother, learned about high-tunnel culture while attending a regional extension seminar on new farming opportunities. Jeff Casey embraced the idea after learning of a U.S. Department of Agriculture program that would pay for an initial 900-square-foot tunnel installation.
The Caseys purchased five additional 2,500-square-foot tunnels at a cost of about $5 per square foot.
The family, known for a decade for its U-Pick blueberry enterprise, sought alternative crops as the blueberries neared their natural lifespan and because of less-than-ideal clay-based soil on the farm.
"In farming, if something's not working, we don't keep doing it," Strickland said. "If we're static, we'll be out of business."
Beth Gray can be contacted at email@example.com.