you could rent a small jackhammer. the posts have to be in the ground to provide stability.

Might have to do that - thought about renting an augur to mount on the PTO but DH says that makes too big a hole (want only 2" OD) plus trying to get it done this weekend.

DH and my dad are going to try breaking up small amounts of schist and forcing through the smaller rocks (may only be hitting something 1-3" wide and 2" deep) with some steel rods, a horseshoe stake, etc. any hardened steel before driving the posts in.

My uncle also had an idea of trenching and burying cinderblocks as anchors with steel cables running to the 4x4's. Can't dig down middle interior (I have about 20 yds of composted manure there now, and don't know if tomato roots over the years would break up the concrete) but can trench on either side. Should do it for drainage anyway. Opinions? How many cinder blocks per foot of length on a side? 14x65 ft tunnel.

DH got the first side (22 posts) in with the use of the horseshoe stake - some are 38" apart as planned, others are 33 and two are only 31 since there were some rocks he couldn't work through but we started on the 2nd side, about halfway done now (12 to go). I'm measuring each post on the first side from the north end, so can line up posts on other side in pairs. Now after lunch starting from the south end (where the posts are a little closer together, that 31" pair and a few 33"). First side all clamped to BB, had to charge drill, going to clamp the other side now. Put some hoops in, they're bent from snow load and some ground posts are leaning to inside or outside a little depending on how the rocks forced them but we're hoping to cherry-pick the hoops that fit the best, may have to adjust height of ground posts (some go in deeper, none will be pulled up but we can drill through and screw hoop in higher if needed) to get them all about the same so we don't have valleys for rain to collect.

Not perfect, but you get what you pay for - so far I've just bought 4 dozen new 1.5" pipe clamps (still have to order cross connectors for purlins, plastic, wiggle wire, parachute cord). Used hardware and imperfect site, best we can do. Definitely not leaving plastic on top over the winter (read if you lace it, you can just undo it from 1 side and pull it over the other, leave it bunched up under the cord).

Will post pix when we get all the hoops in place (though purlins will be next month).

Thanks to everyone for help - I'm sure I'll have more questions as we go along.

Our place use to be an old hog farm with lots of outdoor dirt lots. They had concrete pads with waters and feeders sitting on them. When they dug the basement for our house, regraded the ground and the field around us, I think they just buried the concrete pads or they broke it up in large chunks and buried it with all the dirt. When I was putting up my first big high tunnel I hit the concrete slab about 1.5 to 2.5 feet down. I tried everything but renting a jack hammer to break it up. I was able break a big chunk of it off, but I only went 6 to 10 inches more and hit more. So I dug the hole bigger around and just concreted it in. Fast forward to this spring when I was putting up my new high tunnel and I drove in all the posts and didn't have a single problem. Then I was digging post holes to set the endwall 4 by 4's and I encountered another hunk of concrete 2 feet from my corner post for the high tunnel. I was incredibly lucky to lay out the tunnel and not hit the concrete with the ground post. Well I was only able to dig down about 12 to 18 inches so I made the hole larger and I was able to use concrete bolts and some angle iron and I just bolted the bottom of thewood post to the concrete pad. I know for a fact that post isn't moving anytime soon. Some day I will cuss myself if it has to come out. This concrete was about 35 feet away from the other concrete piece.

If I had time and if I didn't already have the whole structure up (with the exception of this post, I would have dug out that concrete or at least defined it's size and decide what to do.

Long story short, you never know what you are going to hit when you dig holes or drive posts. Do your best to get the posts in the ground as far as they can go. Sounds like you have lots of work ahead of you. Good idea on sliding them around a few inches, that shouldn't hurt anything.

Jay

When we built our HH there was a two and a half foot stump right inside the walls. Small for western Oregon. It was previously a strawberry patch and I just planted around it. So I thought, no big deal, we have a Kubota. Oh my word, was I wrong! Underground it was twice that size with giant roots going every direction. I ended up digging, burning, and chainsawing. It put us back a month, and looked like a bomb crater when we were done. But we didn't have a single rock! :)

Depending on how big the rocks are you can pound a solid steel bar into the ground and then hit it on the sides and pull it back up. Sometimes a digging iron can loosen a few smaller rocks but if you hit larger rocks I would rely on the baseboard anchored to all the pounded pipes to hold the structure down. One foot deep isn't very deep at all so you might want to dig a slightly bigger hole and pore quickrete around those pipes.

I wanted to go 30" down on my ground stakes and I dug 14-16" then pounded the rest to slightly varying depths but all of my 2" ground stakes were "Boogered" on the tops from pounding so I set up my transit, marked them equal level to the lowest pipe and cut them all level with a 18V cordless sawzall. You would not need to have the whole structure level but if you have a grade it should be a gradual slope to pipe keeping height from ground similar.

If you bolt a clamp from the baseboard to each stake also put a techscrew through the clamp into each pipe. That way all the pipes are held in unison by the baseboard and I doubt you'll have issues. It is far more likely that the weight of snow or ice will bend your arches and colapse the structure than it lifting out of the ground.

Thanks - the hoops are already somewhat flattened from snow (or rain? I don't think they left plastic on over the winter). We're not leaving it covered over the winter.

The pipes/posts are clamped onto the 4x4 BBs, but the PO just had nails driven through holes in the pipes to set the hoops on. I know it will lower them a little (we had to take some out for our site) but I do want to drive screws through those holes once we get all the hoops adjusted.

Are tec screws machine screws? We just have a cordless drill - strong enough to drive the point into the hoops?

tek screws have self drilling points so supposedly you don't have to drill a hole in the steel and then in a separate step put a screw in. they work well with impact drivers.

Well, the holes are already there, it's just a matter of pulling the remaining nails out and putting the screws in - as long as we can make them bite. Don't have an impact driver, don't even know if they make cordless ones.

PO didn't even have these all clamped to the BB - and this wasn't a foot into the ground either!

Any ideas on anchoring the base to the ground, since 1ft deep pipes (and some are loose) aren't going to hold it? I'm also going to lace over the top of the plastic - may add hipboards and gutters/rainbarrels later but I'm tired just from construction this far, and can't see having the time to put them on later this summer.

BTW, DH pointed out that original only had 1 ridgepole, no side purlins, I need to order connectors, would need to buy more 1" OD pipe for 1 side, should I do that or since not leaving covered over winter would ridgepole be enough (22 connectors instead of 66)?