Polycarbonate and acrylic have better R-values, hovering around the 2.0 range for both, depending on the thickness of the material. Growers need to decide what is more important, heat retention or light transmission, which will be largely determined by the crop grown, climate, and time of year it is being grown. The lower the value, the less the insulation quality.) Of course, the thickness of the material will also mean less light entering the greenhouse. (The R-value is a scale that evaluates the thickness of insulation. It has an R-value of 1.4, when doubled up and inflated, while 8-mm twin-wall poly bumps the R-value up to 1.5. Six mil double polyethylene is essentially the standard minimum thickness, according to Rick Hannigan, of Warps, a producer of various plastic products based in Chicago. For this reason, Floral Plant Growers, with locations in four different states, has chosen to use double poly in their northern houses. This pretty much rules out glass as a covering, which lets in maximum light, but doesn’t insulate against the cold very well. Northern growers need to fire up their greenhouses in late winter and early spring. Energy considerations Next to labor, energy is the biggest cost greenhouse growers face. Understanding these considerations for coverings will help you choose the appropriate greenhouse glazing and possibly save money in the long run. Ask yourself, ‘What is my payback and how long will I own this business?’” “Things have changed over the last 40 years. “You need to weigh in a lot of factors,” says Jess Roethle, corporate facility manager at Floral Plant Growers in Denmark, Wisc. In the ever-changing business climate we’re in, it’s important to consider just how long you plan on being in business producing a particular crop. Greenhouse growers have many variables to consider before they make a substantial investment in a greenhouse covering, such as crop type light diffusion and transmission the R-value (insulation measurement) of the covering to allow or not allow ultraviolet (UV) light and geographical location. If only the choice in greenhouse coverings could be so simple.
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |