Tractor Supply is a national retailer that offers a wide variety of products for farmers, ranchers, and homeowners. They sell everything from fencing and livestock feed to tools and tractor parts. While they do not sell greenhouses directly, they do sell a variety of greenhouse accessories.
These include fans, heaters, vents, and thermostats. Tractor Supply also carries a line of greenhouse kits from a company called Solexx. These kits come in a variety of sizes and are made from durable materials.