Straw Bale Cold Frame zone 6b?

[bwaynef]

Originally Posted by CapnChkn

I would prefer to make a bale structure and develop a passive heating system.

What're you thinking about doing as far as passive heat?

[CapnChkn]

What're you thinking about doing as far as passive heat?

I've been playing around with a few ideas.

Solar collectors with tubing running through them and banking the heat in insulated water tanks seems like a good idea, as the sun only heats during the day. Tubing running just under the wall would then warm the interior by radiating that heat, running the water through that tubing. I.E. during the day, the water would be run to collectors storing that heat in tanks, during the night or on cold days, through the walls to radiate into the interior.

Solar collectors that have tubes made from cans and painted black can create a lot of good heat. A fan blowing air from the interior and the return close to the floor. This will only heat during the day.

I'm finding a pile of leaves will heat up to 140°F (60°C), unless I've added nitrogen by adding the old compost to them. If I put a heap inside the structure, the heat should stay inside as well as carbon dioxide.

Not really passive, but building a thermal mass heater could keep the whole thing warm on really cold nights. Heating a chunk of stone, sand, and clay should act to radiate heat into the interior. That takes a firing chamber, chunks of wood, and turbulence to mix oxygen with the hot "cracked" gases.

[Cole_Robbie]

Here are a few links I had saved from my own research into the subject. I think using solar energy to heat water is a great idea. You can also move water uphill without electricity.

http://www.builditsolar.com/Experime...w.htm#Overview

http://www.builditsolar.com/Experime...nstruction.htm

[Tracydr]

I use a lot of passive heat to keep my delicate plants like peppers and eggplants alive in the wintertime. I plant them near large amounts of concrete and brick, like the house, knowing that I want them to survive through winter. Then, just some blankets and at worst, Christmas lights and fans, I've kept them alive through the nights down to 22 degrees. I always water well if it's going to be cold, too.

[Alpinejs]

I have a passive solar water heater on my roof. If you are considering solar
heated water for heat, I suggest reading up on "thermosyphon" as it eliminates
water pumps and any moving parts. Unfortunately for me, my geography doesn't
work out for thermosyphon for my hoophouses. The concept is simple: hot water
rises, so the collectors have to be lower than your storage unit which then
displaces the coldest water in your storage. It requires a pressure relief valve in
that the sun can heat the water to a boiling point.

[CapnChkn]

Thank you everybody! This greenhouse is still in the "find a place to put it" stage. Now is the time to see what to do about heat though.

Tennessee has long stretches of cloudy weather in the winter. We might not see the sun for weeks at a time. I have managed to get heat up to around 180°F (82°C) in January when the sun is shining, with a cardboard box and some plate glass.

I've been out watering, removing dead leaves, fretting over aphids, and the wall is really warm to the touch. Something like a bath. If it weren't for the fact I need to stir the compost every so often to keep the oxygen up, I could run the tubing through the heap.

[CapnChkn]

Well, the first experiment is over. It certainly works as a cold frame. Over the winter, I lost around 75% of everything I put in there. Super Beefsteak tomato cuttings survived fairly well. The potted eggplants are still kicking, though I lost one and all the cuttings.

I might have done better if I hadn't forgotten to cover them one night it dropped below freezing. I killed 50% that night. Pepper cuttings ended up coming inside to take up some residence in the lighted grow box, and any seedlings I put out there died fairly quickly.

The compost heated wall and barrels of water worked until the compost finished, and this is when I discover spring is probably the coldest part of the year for them with the wind and all. I never got the pile to heat again satisfactorily.

Now it's swarming season for the bees here, I've been concentrating on them and the raised beds are sitting idle. Still waiting for the carrots to come up, and still covering the plants, they seem to be doing better. Brandywine, Cherokee purple, Sorrento, and Costoluto Genovese seemed to make it alright in the chill. Rutgers, Yellow Pear, and Mortgage Lifter died badly.

One real problem with my Kludge. To get to the plants I have to take it apart and crawl around on my knees to take care of anything. Of course the compost would have been good heat if it didn't cut out at the wrong time and in a nod to Patrix, I think bottom heat would have been better.

On the plus side, it stood up to the winds rill gud. One reason why I don't have anything but the skeleton of a hoop house here, the wind just rips the plastic away. I've never been able to resolve that problem.

I'll try to get photos set up, I've got frames to build, swarm traps to set out, feeding to keep up, and boxes to build for the hives soon to be bursting with new golden babies. No queen cells here in Middle TN yet, but I have frames solid with brood from one end to the other. That's a warm fuzzy feeling, kind of like when the newbees land on you to see what they smell, and get a little taste. They don't bite until they develop teeth...

[zeroma]

Ha ha enjoyed the Jury-Rig "making-do" comments. Not about gardening, but my F-I-L always thought Vasoline was the fix for just about anything from a burn to a "splinter drawer-outter" to any scratch or scrap of the skin! Had he been a gardener, heaven only knows what he would use it for.