Can you please inform me about the differences in poly for greenhouses. As I understand it some kinds of poly "diffuse or radiate the light" so light hits the plants from all angles. What exactly am I looking for in this regard? thank you Conrad
Diffusion under poly has been studied quite a bit, I have an article by the Corvallis Research station specifically on this topic. In short, the multi-directional light that is produced is beneficial to growth of plants that have a "thick" layer of leaves, like shrubs or vines. "Flat" growers like alpines, groundcovers, etc. would benefit little from this. Light intensity is reduced compared to direct sun, but the plants are able to use a higher % of this diffused light, resulting in increased growth. Also protects some against sunscald in very hot sunny weather. As you shop for poly, you will notice IR/AC which I believe will become the standard for most purposes in the future. This poly has glass or silica mixed into the plastic before it is formed into sheets, which does increase the diffusion, as well as retaining infrared heat better at night (and reducing condensation thanks to a different coating on the one side of the sheet, tho this only lasts about one season I believe). This poly should pay for itself if you need to heat your structure.