The problem is that I've yet to find a fabric that would be strong enough and come in large enough sizes.
Does anyone have any ideas?
ETA: If you do buy shade cloth get the knitted and not the woven. Knitted is a stronger product.
I could of course spread the shade cloth over plastic mesh, but that is one more layer to deal with and would reduce the breathability of the structure.
A place I worked at many years ago had several glass greenhouses. We were located in middle GA in probably zone 9. We always "whitewashed" the glass greenhouses each spring. Mixed it up and applied with a garden sprayer. They make a special coating that goes on and over the course of the season slowly washes off the glass. It definitely kept the GH cooler than the bare, clear glass. I don't know where to source that any more or if it would be compatible with plastic covering on a GH.
I hear you on the radiant cooling at night. That is my biggest obstacle as well.
Walt Chase wrote:A place I worked at many years ago had several glass greenhouses. We were located in middle GA in probably zone 9. We always "whitewashed" the glass greenhouses each spring. Mixed it up and applied with a garden sprayer. They make a special coating that goes on and over the course of the season slowly washes off the glass. It definitely kept the GH cooler than the bare, clear glass. I don't know where to source that any more or if it would be compatible with plastic covering on a GH.
We used to use a product called "Glass Wax" for this - it was a glass cleaner. It came in a small can and you diluted with water before spraying it on. Anything that didn't slowly wear off could be rubbed off the glass at the end of the season with a towel. I don't know if the brand is still available, but that might give you more info to go on.
1) It is comparable to the price of 4 mil construction sheeting at "big box" stores.
2) I was able to find the width I wanted Of 30 feet. Comparable price plastics came in 10'-12' widths, so I would have to find some way to splice the plastic.
3) Assuming it lasts me a full year, it will cost about the same per year as what I've found for actual greenhouse film.
4) I expect it will allow sufficient water(rain/humidity) to pass through, reducing/eliminating the need to water and preventing excessive humidity.
5) It will retain heat and reduce the possibility of excessive frost(zone 7b), but I also hypothesize that it since it is breathable, it will reduce or eliminate the need for venting during warmer days.
I do not expect to grow tomato's in mid-winter, but my goal is to achieve a space to grow cold weather crops through most if not all of the winter in my climate, be able to use the space to transition spring transplants to the outdoors, with minimal daily upkeep such as watering or adjusting venting. Without the higher costs of other alternatives such as automatic venting, irrigation lines.
I just recently completed the install, and it is warmer inside, but I haven't tested the temperature difference other than with frost on the ground outside during early/mid morning, I am not unbearabley cold inside with just a T-shirt on.(that may be attributable partially to an increase in the wind chill temperature and not the actual temperature as the fabric reduces wind speed.)
During install, I did notice that it snagged and ripped easier than a plastic would have, but overall it seemed like it would be at least as durable to wind as plastic would be. Snow is minimal in my area, but In areas with snow I believe, because it isn't as slippery as plastic, it would not shed snow, and because it snags easily brushing off the snow would not be an option.
I will try to remember to follow up with the success or failure of the system. I would also be interested in knowing if you found something that worked.