Sigma greenhouses have a traditional look, with a galvanized steel frame and twin-wall polycarbonate panels. Sigma Gen III is rated for 4.5 ft (55 psf) of snow and 65 mph wind, with a 10-year warranty.
Sungrow greenhouses have a modern, heavy-duty, bell-shaped design made for backyard growing in harsh climates. They're rated for 6 ft (75 psf) of snow and 65 mph wind, with a 10-year warranty.
