I've really enjoyed all the greenhouse discussion. Mostly Brian's two earlier threads when he was building his greenhouse. Very interesting and informative.
My greenhouse is in Alpine Texas at 4500 ft elevation in a sunny dry climate. I'm about 300 miles SW of Mark, drier, cooler, and more sunny. It's 54x32x16ft tall. Built myself in 2005. Used for hobby at first, then 7 years growing and selling fig trees, now back to hobby growing. Cooling is wet wall and three 36 inch exhaust fans. I can maintain low 90s all summer with no shade cloth needed.
I'm growing nectarines, peach, apricot, pluots, sweet cherry, mulberry, figs, citrus, mango, banana, and grapes.
What's different about my production system is a chill cycle of 45 days in winter to get chilling for stone fruits. I can achieve 700+ Utah chill hours by heating to 42 at night and holding daytime at 65 or below. Citrus take's the chill cycle in stride, the mango and banana aren't too happy but survive. Next winter I'll install a 20x10ft greenhouse over some of the mango to hold about 15F warmer during chill cycle.
I started out with normal 6 mil double layer inflated poly on the roof. That lasted 2-3 yrs before losing inflation mostly due to hail. Then went with a woven poly called Solarig. It's a massive improvement over 6 mil 4 yr poly. It was totally problem free for 10 years. Now I have Palring 175 double layer inflated. It's the best yet. Cost marginally more than 4 yr and lasts 3x as long. If I built another GH it would be 100% covered in Palring double layer inflated. If someone wants single layer, then Solarig would be a good choice given more diffused light than Palring. Double layer Palring gives high light level inside with some IR retention in winter. From what I've seen Palring is the most cost-effective GH covering available.
https://www.robertmarvel.com/greenhouse-coversYesterday I harvested my first nectarines. Like Millet I really appreciate a warm sunny place to grow things even when it's cold and windy outside. The GH is the best money I ever spent. It paid for itself many times over in profits and enjoyment.
Congratulations Brian on your GH. And I greatly appreciate all you've contributed here. Very informative..!!