How long is your tunnel? One of my four tunnels has no roll-up sides, only the two endwalls that open. It's about 40 feet long and the endwall ventilation was sufficient even on our hottest days (85 degrees) in July/August. Another thing to keep in mind is that fall sunshine is weaker, so the temp. differential between inside and outside will be less than in the spring.

you need to use through bolts/screws for the connection between the bows and the posts. not sure of the size bolt...what size are the holes in the ground posts?
if you don't plan to cover the house for the winter then it seems best to me to just use row covers and use new film in the spring. you have no market for winter produce?

The tunnel is 65ft so I was wondering if on warm days this fall opening the end walls would be enough.

Randy - I barely have a market now - it ends Oct 1 and I don't think I'm going tomorrow since it will be over 90 degrees, on asphalt, and all I have is beans (have to see how many I pick tomorrow, only got a few lbs yesterday), 6 pints (maybe more tomorrow) of cherry tomatoes and a few lbs of Black Krims I picked a week ago that aren't mushy yet. Oh, and 1 Brandywine, a few zukes and some baby bok choy and tatsoi. Everything else is just ending or just starting, and most of the tomatoes are still green. I think these 3 days (M-W) are the warmest it's been since 4th of July! And a cooldown coming for the weekend.

Not to mention in real winter, no heat in the tunnel, no water, and it's 1000ft away from house through woods along an old logging trail I can drive, but not plow.

No way I can cover the indeterminate tomatoes with row cover, I have to put plastic or something over the hoops so it doesn't touch the plants in case of frost.

The holes in the ground posts are just big enough for some pretty big nails they had in there (with hoops resting on top), but I'm not sure what size. Do screws have to go through the hoop (no holes drilled in those) or just into the metal a bit (or even just a machine screw up against the hoop)?

I measured with a drill bit, the holes in the posts are just over 7/32, a 1/4" bit didn't quite fit.

Got the plastic and the wiggle wire, any advice on the screws to secure hoops to ground posts through those 7/32" holes? We need to adjust the height of some of the hoops as well as wanting to secure them to the posts to keep them anchored.

Tomatoes are coming in all at once these past couple of weeks. Hoping to extend the ones in the tunnel well into Oct since I have a lot of green ones but we have to get this done by Sept 28.

ideally 5/16 screws. i think i have 1/4" on some which is close to 7/32.

I figured that, but pointed like wood screws, flat like machine screws, I don't know if they're supposed to go into the hoops (not sure cordless has enough torque to drive the point into steel) or just hold against it? Thread - how coarse?

It's supposed to rain tomorrow afternoon (we need it) but be in the high 40's next couple of nights and 45 Sunday (AM?) then it will warm up again. Not sure how the peppers will do - might need to get some row cover on those and the squash, tomatoes should be OK for those few nights.

Oh, if I want to get actual Tek (self-drilling) screws, I don't know if I'll find them locally, or if I have the time to order online, but Fastenal has different point sizes, does that matter? I'm assuming a pan head might be best but we were careful to place the ground posts with the holes running the length of the tunnel so screw head wouldn't contact plastic, so maybe hex head is better? Stainless would be best but is it the ONLY material I should be considering? Forget bi-metal, I assume heads could eventually rust or break off, if we ever want to take this down that would be a hassle?

Thanks

i was thinking in terms of screws that go all the way through and you put a nut on the end. machine screws or carriage bolts.

Oh, I don't know if I can drill all the way through the hoops. What kind of drill bit and how much torque would you need to drill a hole in galvanized steel (I don't know thickness of the wall/OD and ID)?

depends on the gauge of the steel but a sharp bit makes it pretty easy. the bit would have to be long enough to go all the way through and the width of the screw you are using. if you use tech screws instead of through bolts i would use a couple for each post and drive them on opposite sides.

Thanks, that's a good idea, I don't think we have a sharp/hard enough bit to go through the steel. DH tends to break them - he's hard on tools. I could buy a new one with the bolts but I think carriage bolts tend to be bigger diameter anyway?

Any idea on material/point/thread? I'm still waiting to call restaurant to try to market my tomatoes (lunch starts at 11:30, I'm hoping they'll answer the phone at 11 so I can set up appointment to bring maters by). Then I've got to get diseased leaves off, maybe I can order screws and get them early next week (if you think peppers and squash will be OK with lightweight row cover at 45 degrees) or run by Home Dept tonight.