Polycarbonate Greenhouses

I must confess, polycarbonate greenhouses are my choice every time over a glass greenhouse. I love the looks of a glass greenhouse, and I understand that they have their place and purpose. But, I am more of a form follows function kind of grower.

We started using polycarbonate in our local installation business in the early 90′s. Then our choices were 8mm clear twinwall and 16mm clear triplewall. Oh, there was also bronze and opal. Neither one of them serves much purpose for a greenhouse due to the low (usually 30% to 50%) light transmission. So, being in the deep South, we usually opted for the 8mm clear. The 16mm was more expensive, and we really did not have the need for the extra insulation.

Most of the hobby greenhouse kits today offer a choice of 6mm clear twinwall, 8mm clear twinwall, 8mm clear triplewall, 16mm triplewall and 16mm 5 wall polycarbonate. Some manufacturers will offer specialty polycarbonates as an upgrade.

If you are building your greenhouse frame yourself, there are many more options for you to choose from. There are specialty polycarbonates such as Lexan Thermoclear Plus Softlite, which offers 100% light diffusion. Also, there is Solexx glazing material which offers 72 – 77% soft diffused light. Although, Solexx is polyethylene rather than polycarbonate. Polygal offers 8mm Polycoolite which reduces excess heat while letting in high photosynthetic light quality and quantity. There are sheets such as Lexan Thermoclear Plus which have a higher warranty than most polycarbonate sheets. All I can say is that the options have changed a lot in the last 20 years.

Polycarbonate greenhouses do have one downfall that I can think of. If you want to stand outside and see what is inside clearly, you cannot. Looking down the end of a polycarbonate sheet is like looking down the end of a cardboard box. You have the sheet on the outside, the sheet on the inside and the rib that runs between the sheets. In the cardboard the rib will be wavy. In the polycarbonate sheet the rib will be straight between the two outer sheets. The rib is what distorts your view. I had a beautiful red begonia which I took into my polycarbonate greenhouse year after year, until she finally gave up. From the outside I could see the green of the leaves and the red flowers, but I could not tell you if it was an impatien, a geranium, etc.

Most polycarbonate (be sure to check with the manufacturer) will have a warranty that it will not vary in light transmission more than 6% in ten years. Which is a fancy way of saying it won’t turn color or get brittle. It also has a ten year warranty against hail damage. Polycarbonate is an excellent choice for greenhouse glazing.

Tammy Wylie has been selling and installing greenhouses since 1993. She currently owns two greenhouses personally. A smaller 8 x 12 is used to overwinter plants. Her 18 x 24 greenhouse is used to start vegetables, herbs and annual flowers. She also tests new products in this greenhouse and evaluates them for efficiency and user friendliness. She is the owner of http://advancegreenhouses.com.

For more information on this product, visit this page: http://advancegreenhouses.com/polycarbonate_greenhouses.htm.