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Planning a hoop house

Posted by ajsmama 5b (My Page) on
Mon, Sep 3, 12 at 8:52

We got hoops! I didn't count, but Uncle Harry said 46 and maybe we can get more as he clears them out (he said 14wide x 135 ft long hoophouses, I don't know if we'll set up a long one like that or maybe do 70-80 so we'll need a few more hoops to do 2 side by side).

Anyway, given these are just over 6ft in the middle (I am 5'2" and couldn't quite reach the center ridge pole, maybe they're 13.5ft diameter b/c I don't think they're 7ft tall) and roughly semi-circular (a couple are bent from snowstorm last year, but they were originally 1 smooth arc), I'm trying to plan out bed(s) for inside, as well as shopping for plastic or fabric to cover.

If it's 14ft diam, that's 44ft wide plastic to cover (plus enough to lay on the ground). What are standard sizes for width and length? Plastic would obviously hold the heat in better but since I don't have irrigation, I would have to take it off (or mostly off) during the summer for rain watering. If shade cloth comes wide enough, would that be better or would it be totally useless for extending the season (anything heavy enough to hold heat in would shade too much)? What if I also used mulch (currently using burlap and hay) to warm the soil first?

Sorry, so much to learn, I have read Eliot Coleman's books (have to buy them) but the lack of irrigation is one of my biggest hurdles (the rocky ledge soil is another so I plan on putting in raised beds, which also limits how high the plants can get, unless we buy new lumber for the sides of the house(s) and make them higher. We already plan on clamping the pipes to the sides, can't dig out 100 holes in our soil to bury the receivers Harry used.).

I have strawberry, blackberry and raspberry plants near the house where I can water them. I was planning on veggies for the hoop house(s), I know early tomatoes would be great sellers, and if I am to keep growing peppers I need to get them in early too (so frustrating to have them coming in Sept, and only getting 2 good-sized bell peppers off each plant!). I am flexible on the bell peppers (though I have to grow some hot peppers for DH), the tomatoes are a must, but any other suggestions for dry farming crops in a hoophouse would be appreciated. I'd love to do melons but don't think I can count of keeping them watered enough. Thanks


Follow-Up Postings:

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RE: Planning a hoop house

I just ran a garden hose into my hoop house and watered with it.

Congrats on getting the hoops.

Farmtek has film and shade cloth, various sizes.

My shade cloth was given to me, and doesn't cover the house completely, but does cover all but 6-8' on each side. The cloth cools my house down about 20 degrees, and well worth it.

This year, I used most of the house for growing plants and a small amount for inground veggies. I planted some peas, beans, zucchinis, lettuce, beets, onions, carrots. Most everything did as well in house as outside, just a little earlier. I could have planted even earlier, and will probably next year. We made 1 permanent bed on the south side of house. about 3' wide and length of house. Filled it with well composed horse manure and left=over plant dirt. I want to to put a couple of soaker houses down each side of the bed.


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RE: Planning a hoop house

Ajsmama-

Putting on my middle school math teacher hat on here.

Circumference formula is C=2 *3.14* R. Or C= 3.14*D

That would mean that your Circumference is 43.982297150257104 feet.

The hoop house is only half that so you will only need about a piece of plastic that is 22 feet wide.

Congrats and good luck!

Jay


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RE: Planning a hoop house

My hoophouse has single layer Agribon row cover on the inside and plastic on the outside. This accomplishes the dual goals of daytime heat and nighttime heat conservation.

If heat retention is your goal, don't use organic mulches like hay or burlap. They will lead to cold overnight temps. inside the hoophouse (especially if you don't use row cover) because the soil is unable to warm the air. Bare soil is best.

Summer crop suggestions: okra, sweet potatoes, eggplant.

In my hoophouse, I plant chard for the spring, eggplant for summer and spinach for fall. To save time, all are transplanted.


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RE: Planning a hoop house

Oops, sorry, I used D instead of R when figuring C=2piR and then dividing by 2. Sounds much easier to find 22ft wide plastic. What do you recommend for height and bed spacing? Without sidewalls, I might just have enough height for 1 row of tomatoes down the middle, and shorter plants on the sides. So I would like to build 2-3ft tall sidewalls, and attach the hoops to the top of those, then roll the plastic up to the top of the walls to vent, though that still won't help get rain in.

Marla - I don't think I would get much water pressure even if I could find a 1000ft hose to reach from the house. We've got to get a gas- or diesel-powered pump and a foot valve for the pond, then run the hose/pipe across the roadway. Until then I've got to haul water in 50-gal barrels in the pickup and water by hand. No electricity, no well (just spring-fed pond) out back.

Slimy - thanks, tried okra this year but only 8 plants and it's not even enough to do anything with, I don't know how it would sell here? Eggplant is an idea though (along with the tomatoes of course), and we love sweet potatoes. Do you mean you use low tunnels or row covers with Agribon inside the high tunnel, or do you actually have Agribon over the whole tunnel (and how do you get 2 layer then - Agribon permanently attached to the underside of the hoops?)?

Do you plant eggplant into the chard (not that chard is a good seller here, might try spinach) and the spinach into the eggplant? Or do you pull each crop to make way for new transplants?

I did get some good heavy duty landscape fabric along with the hoop house - Harry used to set potted nursery plants on it with the hoop over, he used really thin (3 mil?) plastic that he replaced every year, just tore it off when weather got warm. I was looking for something more permanent, since I wanted to just uncover the hoops in the summer and then put plastic back on in the fall to extend the season. The landscape fabric is about 14ft wide, but of course won't cover the full width if I do raised beds of any depth, it has holes running down the middle where his sprinklers were so I figured I'd just cut it in half (of course will have to cut it shorter too, I think one piece is 100ft and another 35ft) and use it in the aisles, if I could fit 3 beds and 2 aisles in 14ft.

Would black plastic mulch be best to warm the soil (and keep the weeds down) until ready to plant? I don't know if I'd want to keep it down, might roll it up when ready to plant since I'm afraid it will get too hot in there during the summer (even with house vented or uncovered).


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RE: Planning a hoop house

I have Agribon over the whole tunnel, permanently attached. Mine is a pretty small tunnel, so the 30' wide row cover from Johnnys worked well. However, you would need a much wider piece (or use multiple pieces). I also use low tunnels with more row cover for additional protection in early spring when a hard freeze threatens (less than 20*F). I take them off during the day because the combination of that many layers of row covers cuts the light.

Yes, I pull up all of the previous crop before planting the new one. They grow like crazy inside the tunnel, so there's little space to interplant. With the chard, I experimented with moving the uprooted plants to an empty garden plot this June. Surprisingly, they re-rooted and began producing again without bolting. Spinach is difficult to grow as a spring crop in a hoophouse because of the bolting issue. I've never tried perpetual spinach though - maybe that would work?

For soil warming and weed control, the best would be clear over black. Next best would be IRT.


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RE: Planning a hoop house

You will not be able to remove the plastic and re-install, sorry. I didn't remove my plastic at all the summer, just stayed out of it. Occassionally I went in to soak the dirt, but otherwise didn't do anything with it. the plants grew by themselves.

Son's greenhouse, he put the black landscape fabric down, like what your Uncle did, he removed what he made into beds. Really kept the weeds out.

I used agribon inside my hoop, over the top of 4' wide tables with PVC hoops. 2-3 layers saved my tomato plants down below freezing. Didn't get the catfacing either.

Our greenhouse is only 50' away from a hydrant or electricity. We broke ours in half because we didn't have enough room for 1 entire length. I'm very happy with the 45' length that I have. The professional greenhouse that I've worked for has 15 individual greenhouses. They could have put them all together, but they decided against it. They do have 1 acre sized one, but all others are 45-90 long. By having smaller greenhouses, they can heat the ones they want, and leave the rest alone. They can also separate the flowers from vegetables, which from what I've heard from several people is a good idea.

If you don't get all the hoops up, you can add later. Plus hubby can bend them a little more to store hay in, we have used ours for equipment storage last winter.

Marla


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RE: Planning a hoop house

What's IRT?

Marla - I've got to figure out the water problem. I will consider 45-50' lengths, have to see what the timber (PT 6x6's?) lengths are, join 4 of those together and of course will have to make new end walls since we only have 2 (threw away the door frames, they were so rotten, just kept the "thresholds" to get proper spacing when we put it back together).

What do you think of making taller sidewalls? We'd like to get another just to store the tractors in. We don't need a hay loft. DH wants to put smaller section near the house for propagation, but I'm also looking into getting frame (taller, narrower) from my great-uncle's GH that he has up in the loft of the goat barn, since he bought a new plexiglass GH.

I'm trying to figure out how they're putting on the plastic in this link from hightunnels.org:

Here is a link that might be useful: Low-cost hoop house


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RE: Planning a hoop house

i don't trust the math and instead i measure the ground to ground distance around a hoop. i just did this. the math wouldn't work because the hoophouse is 12' wide and about 7' high. that isn't a circle.
i would also discourage the use of organic mulches in a hoophouse since they provide excellent hiding places for slugs.
i don't see how you can grow inside without irrigation.


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RE: Planning a hoop house

Put the plastic on will depend upon whether you got wiggle-wire or not. Wiggle wire is much easier to work with, according to my son. The greenhouse company that he worked for, they replaced 10 or so each year and he was with them for about 7 years. He got really used to re-covering them. Between him and a friend, they covered ours in very little time. Of course, we have about 4-5 extra people to help hold when needed. Ours isn't wiggle wire, but stapled on with wood strips. I'll see if I can get some good detailed pics and send them to you.

Marla


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RE: Planning a hoop house

Hi ajsmama, IRT is infra-red transmitting plastic. It's more pricey than black or clear plastic but it combines the best of both worlds - the weed suppression of black and the soil heating of clear plastic. It is usually cost effective in a limited, intensive area like a hoophouse.


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RE: Planning a hoop house

We already plan on clamping the pipes to the sides, can't dig out 100 holes in our soil to bury the receivers Harry used.).

And then when the first good storm comes, your hoop house will end up in Kansas. Why do you think he went through the trouble of all those posts? You're building a giant plastic wind sail. You need ground posts along the sides and it's still a good idea to set the corner posts in concrete.

Roll-up sides to vent heat are the very first upgrade to consider. Neighbors of mine didn't want to spend the money when they built their greenhouse; and then they had to buy plants from me because they cooked all of theirs. For a hoop house that long, to use roll-up sides, you want to build it perpendicular to the prevailing winds, so the cross-wind ventilates for you.


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RE: Planning a hoop house

If it ends up in Kansas, maybe it will be near me. If it is usable, then I will put it back up.

aj-You will need to dig holes and bury the posts. You must secure this structure to the ground. If you don't believe me, go out on a windy day and try to hold a 10 foot piece of plastic between you and another person. Now multiply that my 7 to 10. I had two of my ground posts loosened and pulled up by they 55-60 mph winds we had the other night. The soil is so dry around them, the were loose. Now I have a construction rebuild project.

Jay


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RE: Planning a hoop house

We have had our hoophouse up for over a year and it has withstood 80 mph winds. We did NOT dig holes, but we did drive pipes (top rail for chain link fence) into the ground and then attached the pipes to it, screws thru both of the pipes. The reason we were able to get ours, they used rebar and didn't attach the pipes in any way to the rebar.

We haven't had any problems with the sidewalls, but our end walls do need to have some work done on them. We did NOT use removeable sidewalls and we did NOT loose any plants this year in our area. Since you, Sheila are further north, I would guess you would have about the same as us. Of course, as soon as it started to warm up, we opened both end doors (8x8), and put a box fan in.

Our prevailing wind is from the west most of the year and east in the late winter/early spring, and that's the direction the length our hoop house is directed. Our son's also.

Marla


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RE: Planning a hoop house

Thanks Cole and Jay - we have so much ledge, I know we can't secure the end of each hoop in the receivers buried in the ground (sounds like same thing Marla used), we were hoping with the landscape timber "frame" on the bottom that we could just clamp (or DH says drill holes in, but I worry so many big holes so close together will weaken it) them to the bottom frame, and drive rebar though the timbers in as many places (less than 100) as we could?

Been reading up on them and looks like perpendicular to prevailing winds is the way to go, still trying to figure out rope system in first link, or the PA system (link to come - gotta run put DD to bed).


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RE: Planning a hoop house

The corners are the most important. You can dig down to the bedrock and then drill into it, set rebar, and then pour concrete over that. There are a lot of different earth auger post products. The article I put below also talks about stacking a pile of rocks around a post to secure it. You would need the post to have lateral braces within the pile, but it is a neat idea. Rocks are also mass to help even out your hoophouse temps. Be careful, though, about anything sharp touching your poly.

I have read of a lot of homemade greenhouses getting blown away in thunderstorms. I put together a 14x48 Clearspan kit over the winter. Every 4' had a post 2' into the ground and the corner posts were set in concrete. We had 80 mph winds in one storm, and it was no big deal. I'm in an open field with no windbreak; I think it would take about an f1 tornado to blow it away.

Here is a link that might be useful: article on posts in rocky soil


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RE: Planning a hoop house

We have a clay loam type of soil, so we don't have rock in the first few feet of dirt. Our drive posts were driven about 2-3' in. We also have board banding around the entire 22x45 hoop houses. We've tried to put the previous houses perpendicular to the prevailing winds, and had the houses collapse in the winds. That's the reason we chose to place the ends to face the winds, this time, with much less trouble. Ends are easily to repair than sides.

Our son has installed several hoop style greenhouses, professional, and ours are put together as he would for permanent ones. We did put our hoops on 5' spacing, with a drive post on each hoop. Also installed perlins the length at the top and on each side. Each side has a wooden perlin and a top rail about 4' high on each side.

A tip he gave us regarding the poly is, any rough edge, even the slightest, take duct tape and wrap the pipe or whatever to cover the rough spot. It really does help.

Marla


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RE: Planning a hoop house

5ft spacing isn't bad - Harry had his on 3ft spacing, I was thinking we might be able to get away with 4ft if we take the plastic off before heavy snows come each year (so if we use 1 as a garage we'd put them at 3ft). Looking at wiggle wire to be able to take the plastic on and off more easily.

Good point about prevailing winds - though if we do shorter houses maybe we can do perpendicular. I'll have to look into it more - another reason for doing perpendicular is that the pond we'd be pumping from is located to the west of where I want to put the houses, prevailing wind is from north (I think, they really can get pretty variable at least at the house), if we put houses running E-W then we can run the irrigation in the west end - which is also facing the roadway. If we pump into a 275gal tank on top of the hill, that's to the south of the area, but I think it would be harder to run lines into the houses side by side facing E-W so then we'd have to run them N-S to run into south end. So I really have to think about irrigation more than wind direction in planning orientation. Sun too, I'd love to run them E-W to get southern exposure along the length rather than the end.


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RE: Planning a hoop house

I put so much duct tape on my high tunnel that it looked like the project was sponsored by the duct tape company. White is best; it reflects light and does not get hot in the sun. The new treated lumber will also ooze out its treatment chemicals, and that is corrosive to poly. Several coats of white latex paint will help.


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RE: Planning a hoop house

If you do put your hoophouse parallel to prevailing winds, ensure that both endwalls are either open or closed. If one is open and the other closed, it will turn the house into a sail.


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RE: Planning a hoop house

You don't put the duct tape on the plastic, but on the framing. Also for the greenhouse plastic film you don't want to paint it, the paint will cause the plastic to break down faster. Old timers used to use the 'paint' stuff on glass or the last year of plastic.

Don't plan on being able to put the plastic back on after taking it off, It just doesn't work.

I've had my hoop house doors open or closed, and for most of the spring, only 1 open. Worked great until a huge wind storm changed my mind, then I just opened both.

We don't get the super heavy snows, so you probably need to put the ribs at the 3'. I've had to go out and sweep the snow off a few times last year.


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RE: Planning a hoop house

Also for the greenhouse plastic film you don't want to paint it, the paint will cause the plastic to break down faster

I painted mine white for the summer with a diluted latex paint. I have wiggle wire holding the poly down, so I can remove it, but I don't have enough people to help me. It is my understanding that latex will not break down poly, and the paint layer shades some of the sun, slowing the UV damage. I have a supply catalog that sells white paint for shading greenhouses. I have not yet tried to remove the stuff, though. I can't imagine it will be fun.


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RE: Planning a hoop house

I read somewhere that the paint will decrease the life of the film. there is supposed to be a paint for the plastic that isn't paint at all, but it doesn't get removed (from what I understood), but changes from white to clear when the humidity in the house has wetted the plastic. I use a shade cloth that was given to me, it wasn't in great shape with some holes and wearing-out spots, but it worked like it was supposed to.

I did check again with the son that did all the greenhouses. He said not to try to replace the plastic that was installed with the wiggle wire because when the wiggle is installed it will cause either holes or weak spots and the second time it will tear at those places. You might be able to put the plastic back on IF you are going from a larger house to a smaller house. We've done that. Of course, the film will only last so many years before the sun deteriorates it.


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RE: Planning a hoop house

I thought the whole purpose of wiggle wire was so that you *could* remove the plastic? Still haven't gotten a good look at what it is - Farmtek was down when I tried the other day and I've been busy.


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RE: Planning a hoop house

Wiggle wire is to make the installation and removal of the film easier. Trust me, it works. Otherwise, you need several people to install, and hold while 2 other people are stapling it onto wood pieces. We don't have it. And to remove when it's wore out, you remove the wiggle wire and the plastic is able to come off, versus popping each staple.

Most greenhouses don't remove the plastic during the summer, that's the reason for the roll up sides. Plus most actual greenhouses don't keep plants inside all summer. I removed all plants when it was safe, but I wasn't growing much inside. What I did grow inside, did fine without removing the plastic/film. I just left both sets of doors open and left a fan on for circulation.

If you've looked at the price of the greenhouse plastic/film, you won't want to remove and throw away. I got lucky to be given 2-3 almost full rolls along with the shade cloth and several new roll covers.

The only reason I got all of this was my son was working for a place that cleans up repoed houses. This one was a couple thinking that they could make a living off of farm markets and pay a mortgage without working elsewhere. They bought alot of seeds from Johnnys (yes, I got those too, too old and no good at all) and a greenhouse (didn't get it). They bought everything that they thought they would need, but didn't/couldn't pay the mortgage. It was a shame for them, but worked out well for me, since the bank wanted everything 'gone'.

You can find it elsewhere, just google it.

Marla


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RE: Planning a hoop house

when the wiggle is installed it will cause either holes or weak spots and the second time it will tear at those places.

You know, when I was putting the plastic on with the wiggle wire, that thought did occur to me. It did look like it was wearing the plastic, making little white stretch marks. Maybe I'm not so foolish to leave it up all year. I'm glad you posted that, thanks.

I don't like having to run the inflation blower for the double layer all year, but I have read that an un-inflated double layer will wear against itself in the wind.

The shade paint I have seen is meant for the outside. I haven't seen the other kind.

For anyone not familiar with it, wiggle wire is 2 parts. One is an aluminum channel. The other is wire with about a 2" zig zag up and down. Both come in 8' pieces. When installing the wire, you "wiggle" it up and down to work it into the channel, thus the name. The problem, though, is that when your helper is pulling on the plastic to stretch it, you are pressing down with the wire to push it into the channel. It's too much force over too little of a surface area. Sometimes the ends of the wire poke through as well. I don't regret using it, though. I think it is much stronger than screwing down wooden lathe strips.

I used treated lathe strips to secure my end walls. The treated lumber chemical is nasty stuff, so I painted both sides with a white latex. Then the side touching the plastic got white duct tape. It conveniently overlaps on each side of the lathe stick. I don't ever let treated lumber touch poly without at least two coats of paint and white duct tape to act as a barrier between the arsenate oozing out of the lumber and the poly. It will of course eventually eat through the paint and the tape, but hopefully I'm buying enough time to match the life of the poly in the sun.

Here is a link that might be useful: shade paint pic


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RE: Planning a hoop house

You can use two furring strips, it is a very simple, strong and cheaper than wiggle wire. We have 2 by 4 or 2 by 6 hip boards. We attach one furring strip to the top edge of the hip board. Then we put the plastic on and pull it over the furring strip, then we sandwich the plastic between the two furring strips and then screw it to the hip board. The plastic goes over the first one, between the furring strips and then behind the second one. They have never came loose or pulled out. I have had plastic work loose with wiggle wire.

Check out Figure 11 for an image, I can't find mine.

Jay

Here is a link that might be useful: High Tunnels .org


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RE: Planning a hoop house

The treated lumber isn't as toxic as it used to be. They used to arnesic to treat it. It did take care of any insect that tried to eat it.

Jay, we have done it the way you suggested, but it has pulled loose, with a tear where the staples/nails had been. Of course, it did take a few years before it happened.


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RE: Planning a hoop house

Also if you order wiggle wire, be sure to order the channels also. They do not come together.


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RE: Planning a hoop house

i think wiggle wire is the way to go. not sure there is a good way to handle end wall film without it.


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RE: Planning a hoop house

We have a wood framing that we attached the end plastic to. The end plastic is a separate piece.


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RE: Planning a hoop house

The treated lumber is not as toxic, but I think it might be even more corrosive with the new "arsenate" instead of the old arsenic. A seed company I buy from states in their catalog in bold print next to the poly that their year-rating for its life does not apply if it touches treated lumber. By the time I had painted everything white once, the chemical treatment had oozed through the paint and turned it yellow. I wish I could afford to make everything from the new synthetic lumber, but until I can, I'm sold on the two coats of latex and a layer of white duct tape.


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RE: Planning a hoop house

We used treated, but not on the dirt boxes. Most of the wood doesn't touch the ground, except end walls.


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RE: Planning a hoop house

Thanks for all the tips. We did get the baseboards with it, they are about 35-40 yrs old, the really bad treated stuff I guess and they are looking a bit worse for wear, might need to be replaced. We have cedar (lots of our cedar trees are dying), though it will take a while to cut and saw it into timbers.

Considering we got the hoops, purlin, and end pipes/receivers for free (except delivery), I guess we can afford to buy lumber for baseboards, hipboards and end walls as well as plastic and wiggle wire (plus channel). What would you suggest for material if we go buy it rather than sawing our own cedar (in the interest of time)?

This isn't going to be a greenhouse (unless we use 4-5 hoops near the house), I plan on growing in high tunnel(s) like Jay does, though maybe I won't get quite as long a season it would help to be able to transplant peppers and tomatoes May 1 every year instead of waiting til Mem Day (or even June, as has happened the past 2 years due to cold rainy weather), and keep things going until end of Oct of even Nov (though most markets here end in Sept-Oct, I may be able to keep some customers later, esp. if wholesaling works out).


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RE: Planning a hoop house

Those treated ones, being as old as they are, REPLACE them, they are the ones treated with arsenic. Cedar is probably best, unless you can get cypress, but cypress is bad for some plants.

You might be surprised what you will use it for. I just wanted to have a place to take my plants out to when the house becomes overstuffed with plants. Now, we've planted some in some beds, and next year, I want to try some large container gardening. I have some 25-35 gal tree pots and the dirt, why not????


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RE: Planning a hoop house

Don't sell yourself short, you can start planting way before May 1st. I am planning on starting carrots around January 1-15th. They came up in two weeks or less last year. I also direct seeded salad mix on dec 30th. The salad mix was ready by march, carrots were ready in may.

If it were me, I would decide a location, square it up and get those ground posts in before the ground freezes. You can always work on the above ground stuff on the nice days, but it is really hard to get. Posts in frozen ground.

Two years ago, when I built my big building, and had to move the smaller one, I was spending every moment in November and december getting the posts in. Once I did that, mi could pick and choose my work days. Although I worked every one I could to ensure it was done on time.

Jay


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RE: Planning a hoop house

Jay, keep in mind that she's not in KS, but CT. Even I can't work in it in january, and I'm not that far from you, but far enough.


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RE: Planning a hoop house

If you don't mind me asking, why can't you work in your tunnel in January? I know of people north of you in Michigan who grow, plant and harvest using a similar planting schedule that I mentioned.

Two years ago we had several cold snaps that it never got above the mid teens for weeks. During this time, we harvested for market and sold produce. The hardest part was getting the produce from the tunnel to the house.

Just wondering.

Jay


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RE: Planning a hoop house

Most of the time, ground was still frozen. First year with it, might work better this next year. It did make a great garage tho, my Blazer was spoiled. Parts of MI are warmer than I am, if they're near the lakes.


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RE: Planning a hoop house

I actually wished they still used arsenic, at least as an option. It's the new arsenate stuff that is supposedly less toxic to people that is so corrosive to paint and poly. If it were me, I'd use the old boards, if you can get them sanded down to a smooth surface that won't snag your plastic.

I read about an experiment once where they tried to make arsenic-laced vegetables with treated lumber. They took freshly-treated, new lumber and ground it into sawdust. Even using that as media, the only produce they could get with arsenic above the government's safety threshold was root crops like carrots and radishes. And even then, the only part with an unsafe level of arsenic was the very tip of the root, a part people don't eat, anyway.

The synthetic lumber is really the best stuff (no paint, no sanding, no splinters, no poly-dissolving arsenate, and a 100-year life in full sun), but it is of course very expensive.

If you do use some sort of wood and you plant on painting the lumber white, which is a good idea, it's a lot easier to lay the boards on saw horses and paint them before you start building.


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RE: Planning a hoop house

I have never had frozen ground in my high tunnels, maybe the outside few inches, but that is only in the mornings. Once the sun comes out, it is nice and toasty in there. Last year, I was tired of staying inside, so I put up a lounge chair in the high tunnel and took a nice nap in the warm sun!

Jay


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RE: Planning a hoop house

I enjoyed it in March. I need to work on more heat sink. Planning on installing the black fabric on the floors to help with the heat. Also planning on having more dirt inside in big black pots to help out. I didn't have alot of heat sink this last year. Another thing to work on before winter hits.

Marla


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RE: Planning a hoop house

And then there's zone 2. The soil in my high tunnel usually freezes to a depth of 8-12", compared to 3-4 feet outdoors. Complete thaw occurs by mid-March, compared to late April outdoors.


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RE: Planning a hoop house

Went to a workshop on High Tunnels last night. Guy spent a lot of time talking about greenhouses - says USDA allows heat and electricity in tunnels now, though NRCS won't pay for it, if you get a grant and want to add it/them it will be on your own nickel but not a violation. Have to grow in the ground 3 yrs but after that you can use pots, bags, whatever media you want.

Not too much more info than I'd already found online, but he did say I should make my sidewalls no more than 3ft high and put bracing in if I want to use the 14ft hoops. Of course I already knew the shape wasn't the best for snow, and "wider is better" to borrow a phrase but hey, I got the hoops for free.

I have to search online for movable tunnel designs - Jay, don't you have some on tracks?

And he did say that if all I was interested in was season extension for summer crops, can put clear plastic (not black) on ground and cover the hoops about 2 weeks before I want to plant - said even if I had plastic on all winter, it wouldn't do any better to warm below the top 2" or so of soil, if I really want to warm the top 6" for my tomato transplants I'd have to run warm water (geothermal using a closed loop in my pond? Propane hot water heater?) tubes buried in my beds.

Very interesting to hear that with a single layer of plastic, unheated HT can actually become *colder* than outside b/c of radiational cooling on clear "black sky" nights. I hadn't thought of that - guess it's good I'm only looking for season extension, but double layer with a blower would be good idea even if you don't have heat, but have electricity for the squirrel-cage blower.

Sure glad I don't live in zone 2 ;-)

Oh, and someone on Freecycle has some "cement boards" 60'x11.5' (don't know how thick), not quite enough to build a big house (only 15) but it's a start - think I can use those for baseboards since he said he wouldn't use even 40-yr old PT if I wanted to be "organic" (not looking for certification). Couldn't answer whether he thought most of the arsenic had already leached out by now. If we can use the cement boards and get one tunnel up, it will give DH some time to cut some cedar and have my cousin bring his portable sawmill up next year.


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RE: Planning a hoop house

40 year old PT boards have arsenic in them, the newer PT boards are treated with something else.

Yes, it can get colder on 'black sky' nights, that's when you want to have some of the row covers. I used 3 layers and it protected my tomatoes from below freezing nights.

High tunnels are basically greenhouses without heat, and the ends are able to be opened more.

Did you ask the guy 'how long has he been growing in his high tunnels?' I would have. You have a much better source of actual growers here than you would find most anywhere.

Check out countrysidemag.com and look at the past issues. Issue 84 has a really nice article about a farm that has a moveable high tunnel. Unfortunately that issue is sold out, but you can read the article on line.

Marla


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RE: Planning a hoop house

I don't know that he's ever grown anything in a HT personally - he's a PhD in Ag Engineering, does audits for the USDA and does consulting. Retired from UCONN. But has published a lot and seen a lot of commercial growing in GHs and HTs.

The cement "planks" turned out to be concrete slabs 2" thick, if DH can get someone to help him pick them up we may be able to use them as extra-large "pavers" to replace the gravel outside our back garage door where he keeps the grill, but definitely nothing we can use as baseboards on the HT!

Here is a link that might be useful: UMASS greenhouse engineering - Dr. Bartok


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RE: Planning a hoop house

Which volume (or date) Issue 84? I tried searching "high tunnel" and can't find the article you're referring to. Only hit for "high tunnel" and "issue 84" was "Equipping the Ideal Homestead"


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RE: Planning a hoop house

countrysidemag.com, then click on 'past issues', year 2000, click on July/Aug, article about Welcome to Anathoth.

Here's the direct link, sorry I didn't think about adding it on the first post. I was in class and trying to pay attention to Business Law and message at same time, I probably shouldn't do that.

http://www.countrysidemag.com/issues/84/84-4/Countryside_Staff.html

Marla


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RE: Planning a hoop house

The article has alot of extra information that doesn't apply to greenhouses, the actual magazine had pics that the online doesn't.


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RE: Planning a hoop house

Re: PT wood. If you are doing raised beds, lining the bed with scraps of roof poly should stop/slow down the water exchange between soil and board to the point they are safe. This assumes that the wood preservative actually leaches out of the wood, and that plants pick it up.

Re: Anchoring hoops: Yes. Several ways:

A: Bottom end of hoop slips over/inside post that is pounded into the ground. Hoop is pinned to post with a bolt that passes through both.

B: similar to A, but support post is set in concrete.

C: Use fence posts. The hoop is then fastened to to the outside of the post using lag bolts that go through the hoop and into the post. This is the best way if you want to raise your house. Note: Wind force goes up with at least the square of the height.

Ventilation: Roll up sides. Definately.

Irrigation. Google gravity feed drip irrigation.

You can put a tank up 3-5 feet above the garden, pump into that tank, and distribute from there.

As to the 1000 foot hose. I did that. 60 psi water pressure will punch about 1 gallon per minute. So I ripped it out and put in 1.5" System works. I water 20,000 trees with 5 gal/minute.


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RE: Planning a hoop house

OK, update. Hoops are 13'1" center to center, looks like 1 1/8" (OD) galvanized pipe. Couldn't get a good measurement of height or total length the way they're stacked, but I could barely reach the purlin when it was assembled so I will assume that even if they are "squished" so they're a little taller than 6' 6.5" (6'7" allowing for OD), the pipe was probably standard length for top rail - is that 21 or 22ft?

Then of course they were set in "receivers" buried in the ground, with a bell end sticking up above the baseboards they were clamped to, so the ends of the hoops were about 6" off the ground (like B option above). I want to set them up even higher (buy new pipe to drive into the ground, use the old ones to connect them inside the sidewalls?), really like 2ft sidewalls so I can get over 8ft tall in the middle and have *some* room on the sides for crops. Also, I want to put the hip boards high enough to put gutters and downspouts on to try to put a couple of rainbarrels up for irrigation.

Sherwood - when you say use fence posts to raise them up, you mean steel T-posts or cedar fence posts? I'm assuming every hoop.

Here's the problem - I have (I think) 96 hoops that were originally placed 3ft apart, using what I'm sure is CCA treated lumber. I could replace the lumber with new (ACQ or CAB - saw some on Craigslist, right here in town, guy is checking what it is for me, but he's got some 6x6x8ft posts and 19 2x8x8ft planks - that would give me 76ft in length if I used them as baseboards) - but still wouldn't be "organic" (not that I'm going for certification). Probably would have to replace all the fasteners anyway, lots of the clamps look white, not sure how long galvanized lasts even with CCA.

Area where I have cleared is about 48x76, small rise to south but I don't think it blocks much sun (and I'm not growing 4 seasons), I can place it far enough away that I think I can catch southerly breezes (and it's a convenient place to put a tank if I want to pump into it - that's another story since GAP says not to use pond water).

BUT... the land slopes from west to east, maybe a couple of feet over the 48ft width. Area is more level going N-S, with an existing swale to the north. Another rise (long ledge) running to the north, wooded, and wooded to the East (why I don't want to go farther than 48ft E-W, plus it drops off more sharply past that), but clear to the West. Prevailing winds are from the south here in the summer, according to expert in HT design at workshop I took a month ago.

So what's the best orientation and size? 1 (or eventually 2) 76ft long tunnels running N-S (I don't think that's really best, maybe 1 but easternmost one would get shaded and ventilation affected by western one and not best use of prevailing winds), 2 (or eventually more since there's room, but endwalls are more expensive) tunnels running E-W (but have to build up sidewalls to level them on east end, plant taller crops on east?, same problem with shading from southernmost tunnel(s), ventilation affected?)?

Also looks like Farmtek's standard greenhouse film comes only in 24ft or 32ft wide rolls, so no burying edges with 24ft, lots of waste with 32ft if I try for 2ft tall sidewalls? Will 24ft wide work if I plan on rolling up sides anyway, and stack hay bales against the sides during colder months (again, just looking to extend the season a month or so in each direction)?

IF we put the houses running N-S, we could make them shorter than 76ft and then move them since the area is more or less level in that direction. Don't know if that really matters since I'm not sure how many different types of crops I'd be growing, but if going N-S for another reason, I'd probably use Jay's design and make it/them movable for flexibility in the future.


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RE: Planning a hoop house

I used 24' film and then attached a separate piece for the roll up sides (which I attached permanent, after they tried to blow off). that white stuff MIGHT be whitewash, which alot of older greenhouses used for shading. Shouldn't hurt it.

Mine are running E to W, mainly because I have western prevailing winds AND that's the space I had.


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RE: Planning a hoop house

Well, maybe I'll get fancy and make solid 18" or 2ft sides, I've read where sometimes you don't want the sides open all the way down to the ground, you want the cool air to come over the tops of the plants and in, not hit them at ground level. Then 24ft width should be good.

I think the white stuff on the galvanized metal is corrosion, it's not whitewash b/c the wood wasn't whitewashed. After 30 yrs even though CCA isn't supposed to be corrosive to zinc, I guess it's just weathering.


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