I used a similar method with PVC pipe covered with clear plastic. However, I held my plastic down with clamps on the pipe. I used cheap jumbo binder clips, but small sections of larger pipe split down the middle are a better solution that don't rust. Or maybe A clamps from the hardware store. There are pictures on my blog of my setup.

That said, if you want cold protection, I didn't find the hoop cover to provide much. I woild consider a true cold frame.

Good luck!

Here is a link that might be useful: Sinfonian's garden adventure

I use 3/4 black poly over 2 ft 1/2" rebar driven 18" down, 2 or 3-foot separation between hoops. The ends of clear poly-row cover are rolled onto 3/4 SCH40 PVC both sides, and PVC held down by two brick pavers and one paver each end (6 total per unit). The fabric is clipped to black poly by sawing extra black poly in half, smoothing sharp edges and placing every 1-2 feet, depending on whether we get normal wind or a Chinook is in the forecast. Hard frosts get row cover under clear poly and at least one milk jug of water under there (my milk jugs are filled with water dyed dark with food color and a touch of bleach for the algae).

And I agree with sinfonian on the cold frame. I made mine with dumpster diving...found material. One is 2x6 cedar and the other is 1/2 chip board sandwiched around R3 sheathing insulation. Yesterday in Denver we had salad from the cold frame. You can also go on Craigslist (esp now!) and get storm windows/surplus windows from builders going BK for cheap and do your Mel's sunbox thing. I have my eye on storm windows that I might pick up a couple if the MIL doesn't object to another crazy Dan project.

Dan

mtnrunner...send me your email and I will show you what I have done. It might give you some more ideas.

Here's another idea for you..there are 4-7' tomato plants that I cut down from the vertical structure and some other things growing under there as well. This is in late November/early December...

What's that heated with, snibb?

Dan

Dan...its not heated with anything...its pretty much the sun and the plastic. But, it might be 70 degrees in there even though it was cold and snowy outside. Its all very easy.

Snibb:

I have a coldframe, outside of Denver, and have cold seasons in it all winter, but it is far better insulation than that hoop structure. Does it freeze at night? Do you retain heat with water?

Dan

Your probably right on that one. Yes, I am in SLC, Utah, so I would think our weather is similiar. It does freeze at night but because of the heat build up during the day, I think that saves me at night. I have never tried to retain heat with water-I know it would work, but, when it gets right down to it, Im a lazy gardner. The less work, the simpler, the better for me.

Looks like you are in Sunset zone 3x, whereas I'm in 2b, not sure I can make that work here. I've thought about it and I'd sure like to, as it is less work than making a cold frame, that's for sure. As it is my coldframe has opened every day for at least the past 2 weeks to vent excess heat.

Maybe I'll give 4-6 lf a go next fall & see what I can make happen... thanks snibb!

Dan

I bought materials today for making 2 hoop covers for my garden, and should make a final decision on the design very soon. Because of my bed construction, the covered wagon style is not an option. Instead, the other design in the new book will be utilized - after a little creativity is added to it. You know me....always have to be different!

EG

Dan,
I was covering my beds last fall. I found that plastic alone doesn't really hold heat in very well but combined with blankets, I kept plants alive until it was about 18 degrees IIRC.

I did not have water jugs in there at the time which likely would have made a difference.

I use welded wire fence with 2x2 boards along the edge, then cover with vinyl. see link below

Here is a link that might be useful: row covers

I use a row cover underneath plastic to get to 24º. I've never tried 18º, but I'm pretty sure I could get there with water or soil cables. Here the issue is controlling the heat in the daytime and not cooking the lil guys underneath. Welded wire will hold an old sleeping bag overnight, that'll take you way down in temps!

Dan

I am going to try this this year, but using PEX (crossed polyethylene pipe) instead of PVC due to PVC being very toxic and banned in Germany, and PEX is cheap and available at home depot. Kind of like using coir instead of peat because peat is non sustainable and coir is the environmentally sound alternative.

Posted by megmaine (My Page) on Tue, Feb 24, 09 at 10:32
I am going to try this this year, but using PEX (crossed polyethylene pipe) instead of PVC due to PVC being very toxic and banned in Germany, and PEX is cheap and available at home depot. Kind of like using coir instead of peat because peat is non sustainable and coir is the environmentally sound alternative.

I don't want to be the one to burst your bubble, but none of those statements you made are true. Germany reversed their ban in 1995 after exhaustive testing showing that PVC is safe at temperatures that water is provided. Only above about 200 degrees does PVC begin to leach chemicals.

Spaghum Peat is sustainable at the rate it is being used and more environmentally sound than coco coir at the moment. Canadian Spaghum Peat is regulated by the Canadian government, where coco coir production is not.

I urge you to please read real scientific studies on these things and not believe every website that you read.

What jleiwig said.

I'm not sure PEX has the rigidity you want anyways (besides not being resistant to UV), and bending PVC for a span of, say, 4' will be interesting (one is limited by the width of their row cover). Black poly drip tubing is rigid enough yet flexible, and more resistant to UV than PEX. Welded wire fence is for permanance, black poly is for the need for flexible design/application.

One thing we want to keep in mind is that peatlands store carbon, and soon we'll be in a world that prices its carbon appropriately - meaning peat likely will go up in price in the foreseeable future.

Dan

Granny kisses jleiwig and quietly backs out of the room...

Here is a link that might be useful: Annie's Kitchen Garden

Posted by anniesgranny 6b (My Page) on Tue, Feb 24, 09 at 11:02

Granny kisses jleiwig and quietly backs out of the room...

Thanks Granny.

I don't like to label people treehuggers because I'm all for sustainability, but people who just jump on a bandwagon for a cause without really researching about that cause drives me nuts.

So many people are quick to believe anything they hear or read or see on a webpage that it is almost impossible to spread the word about the truth in things.

Last week I was at a place that was blaring John Tesh's radio show over the speakers, and every other commercial break he was talking about this study proving that this thing causes that ailment. Some people go all crazy thinking this chemical causes that or this product produces that when it's all a bunch of bunk.

One thing I learned in years of clinical research is that for every study that you can find for to support a position, I can find two to support the opposite position.

Just like the whole chemical/organic fertilizer thing. Don't even get me started on that rant! Plants cannot physiologically tell a difference between the two, and neither can your body!

Okay...rant off...sorry for interrupting!

So many people are quick to believe anything they hear or read or see on a webpage that it is almost impossible to spread the word about the truth in things.

True, but this is part of the human condition, and is particularly prevalent today (as Google doesn't have a 'wisdom' button), namely: how do we teach critical thinking to such a degree that we eliminate selection/confirmation bias?

We can't, and this is why forums like this exist. And why think-tanks exist, and why K St has been so successful at disseminating their information to certain ideologies (because confirmation bias is a real issue in human learning [or boon if you are promulgating political information to influence policy]).

Also we are nearing information saturation/fatigue and this makes research difficult; I'm currently doing applied research, and I missed a conference in Boulder to submit to - there is just so much stuff to go through out there...

Dan

snibb,

I'm amazed at what you've got going there and especially intrigued as 2" of snow fell overnight here.

You must have some sort of very interesting material covering your bed, yes? On the garden supply web sites, I've seen a broad variety of fabrics claiming a broad variety of qualities (and with a broad variety of prices).

Cheryl

Cheryl..its really is nothing different-its just Mels mix-which is now available commercially by the way-with some PVC "arches" and 6 mil plastic. Its good quite a long time. When the weather gets in the teens or lower, some things dont do well under there. This was only a way for me to get the rest of my tomatoes to ripen, which they did. Its extra work, but, you can really get a major extension out of the growing season this way without it costing you an arm and a leg...

Last winter all my PVC pipes turn into garbage after strong freezing. Best alternative would be PEX but also have issues like UV sensitive. Anyway I will try pex tubing and nothing happens with my pipes whole summer. Because I use pex-al-pex tubing with aluminum layer inside pipe.

Here is a link that might be useful: where to buy pex-al-pex