I did all the anchoring tricks the manufacturer advised and I plan on adding a few more when I get everything finished. The metal hoops making the ribs you can see under the plastic sheeting are driven into the ground (up to 2 feet on the high corner, and a little over a foot on the low corner). The four by four posts that frame the front and back doors are sunk 2 feet into the ground and back-filled with concrete. The original structure was supposed to be 36 feet long with a rib every four feet. I shortened it to 30 due to property line restrictions, so each rib is a little over 3 feet apart and the whole structure is 20 by 30. The main roof is a double layer of greenhouse plastic with an inflator device pumping air in between the layers for insulation, it also provides a bit of stability during heavy winds, snow, rain and hail. There are extra metal pipes anchored to the ribs making rafters. I prepped it for metal cables to be strung from door post to door post and then anchored to the ground - which should keep it from blowing away during a normal wind storm. During hurricanes and tornadoes they advise you to cut your plastic sheeting to save the frame work. I don't have extra plastic laying around so I may not do that. Most farmers use these high tunnels out in open fields where they really suffer during high winds. Mine is better anchored and tucked behind the house and garage so it doesn't get the full force of the wind when it blows. I also plan on boring a few more holes in the asphalt pad and sinking some extra support poles inside to help the roof deal with any snow - if and when we ever get a really big snow storm. I need the poles inside anyway to hang orchids, ferns and hanging baskets so it will kill two birds with one stone. If all goes well and I can really keep it warm in the winter I will probably change out the plastic with some sort of polycarbonate panel. The plastic is supposed to last from 3 to 5 years, so it will be a while before I have to cough up the big money. If I can't keep it warm enough I may just section off one part of it and try to keep that area warm and reduce the number of plants I baby through the winter. Part of the reason to do all this is because I have this nasty habit of starting seeds from everything I eat. I always assume these tropical fruit trees will die (and some of them do) but the survivors and the citrus trees I bought years ago have just gotten so big that I need to plant them in big pots and leave them in one spot rather than ruin my back hauling them in and out of the basement.

Thanks farmhousebound and raee! Of the 3 new ones, I'm leaning towards the FC - one reason being, I need a countertop for my guestbath vanity* and there would be enough left from the kitchen to do the vanity top. But I am wondering if it looks to creamy against the white of the cabinets. I do want to warm up the ktichen a little as my cabs lean more towards a crisp white. No one has commented that doesn't look good with the cab white so maybe it's ok. I'm having such a hard time picturing the white/white with the rest of the space. Ugh! (*I really like Organic White better for the guest bath, but I am also try to save some $, and thinking FC would suffice.) Otherwise, it'll probably be Raven.

For the statistically-inclined, there are two sites that summarize this information for various locations. NCSU has a table of Average Last Spring Frost Dates for Selected North Carolina Locations with average dates and standard deviations. Its introduction text was incorrectly pasted from the fall dates. For the last spring frost, the average date plus one standard deviation gives the date before which there is 84% chance of a frost being the last one (98% for two standard deviations). And then there is the table of Average First Fall Frost Dates for Selected North Carolina Locations climate-charts.com has 10, 50, and 90% dates for individual locations, for example RDU airport (scroll to the bottom of the page).

Are you still having issues? We are looking at having the same material installed, but I am getting nervous with some of the reviews I am reading. I would appreciate any information good or bad!