Background paper on UV and why it matters: https://www.uv4plants.org/wp-content/uploads/2014/10/UV-web-opt.pdf Now, some product sources: Shade Fabric | Coolaroo (up to 90% blockage) Shade Cloths - Canopies - The Home Depot (multiple vendors listed - up to 90% blockage, choice of several colors) Some plants do better at high UV levels - here's why - Plants make their own sunscreen to block damaging rays peer-4reviewed papers and monographs: Effects of ultraviolet radiation on plant cells - PubMed Interactive Effects of UV-B Light with Abiotic Factors on Plant Growth and Chemistry, and Their Consequences for Defense against Arthropod Herbivores Ultraviolet radiation changes plant color
What does the damage look like to the eye? more to follow. For some reason the board keeps throwing a Forbidden flag when posting some items.
Our small (10x10) greenhouse was made with 12mil re-enforced film good for at least 7 years, we get better performance owing to the ability to take the structure down at the end of the growing season. With a UV shade, the greenhouse film will last longer while protecting the plants from damage. Not quite win-win owing to the expense of twin layers in the greenhouse cover. The issue, as I see it, isn't *just* UV degradation, but winds and now, hail. There are 'anti-hail' netting products on the market, and some solar film products claim to be 'hail-resistant'.(insert large salt lick here) There are documented cases where some greenhouse films have survived large hailstones with minimal damage, but the story's leave out the age of the film in use. The same claims are made for glass (hail-proof glass, yeah) and for poly panels. I have my doubts for both. What can you do, past pulling the greenhouse/tunnel sheeting down prior to weather likely to produce hailstones? And even this will expose you plant s to weather damage anyway... To look over the edge of the 'box' there is this: Inside a greenhouse in a hailstorm - roofing is Acrylit High Impact panels (Texas) (banging hailstones) (material - used for skylights in industrial buildings High wind areas tunnel The Walipini is earth sheltered, so good for high wind ares. low energy use. This example is a bit over the top, but lends it self to intensive gardening. The board has featured walipini structures in the past. (The Walipini Earth Bermed / Sunken Greenhouse Walipini Consruction (The Underground Greenhouse) (3.49 MB) Walapini Build with rocket mass heater) (this example looks like a bunker, but hey, it is their place) For a slightly less expensive greenhouse (part 3 of several) So-called industrial glass can be had on occasion from commercial building renovations. It is however, very heavy and require equipment for emplacement - not to mention a very stout (steel is best) support system. However, if you live near an urban area, this may be an option. Use "recycled skyscraper glass" or "salvage high rise glass" Here is an idea of the weight involved Replacing Windows of High-Rise Buildings | XSPlatforms About that 'high rise glass' Curtain Walls | WBDG - Whole Building Design Guide Still, it would be the classic one and done. more to follow.
Why post this series? Error - Cookies Turned Off Global increase in UV irradiance during the past 30 years (1979–2008) estimated from satellite data Zonal average ultraviolet irradiance (flux ultraviolet, FUV) reaching the Earth's surface has significantly increased since 1979 at all latitudes except the equatorial zone. As the magnetosphere shifts/fades, this will become a growing issue - no pun intended. Get ready now, while you can more to follow
Commercial greenhouse coverings - case studies Case Studies Archives - Greenhouse Product News UK greenhouse covering - case studies REF Case study search Impact of greenhouse coverings on insects Field trials measuring the effects of ultraviolet-absorbing greenhouse plastic films on insect populations - PubMed (PDF) Effect of two UV-absorbing greenhouse-covering films on growth and yield of an eggplant soilless crop some case studies from Commercial greenhouse operations. While some UV(B) is desirable,. too much is, well, too much.
