I asked my husband about them and he said he has a drawer full of them, but his are 12 volt and would require something extra. I think I'll look around for the 120 volt ones.

If he had an old 12 volt power supply from a drill charger or something they would work fine. Those small fans move a surprising amount of air. I have 2 in the GH that push air down over the sunward side, to eliminate hot spots on those benches.

Thanks, Ric, I'm sure he has a lot of old power supplies. I just asked, and he said that's what he intends to use. I guess I'll be covered with my grow tent fan.

He sounds a bit like me. A hoarder. I have a barn full of things I may have a use for.

Ha, yes. We are overflowing with things we think we'll use 'someday'.

You guys aught to read the current issue of Low Tech Magazine.

See: http://www.lowtechmagazine.com...

Interesting link! I'm saving it to check when I have more time.

Thanks for posting that link, Tom -- LOTS of interesting info there

mcallis said:If I'm right here the concept is the geothermal heat will warm the barrel at night. Are Temperatures at this depth constant at higher longitudes? Meaning up here in Mass would the ground heat at 4 feet deep be significantly different?

If I was the one you were asking about, no, I don't think burying a barrel 4 feet down would collect any measurable amount of geothermal heat. It might be below the frost line, and be insulated against daily temperature changes.

Maybe in a region with hot springs or volcanoes it would be different.

I just meant that barrels could absorb solar heat, and the warmed water allowed to flow down into an underground reservoir. Then, you could pump cold water up out of the reservoir and back into the barrels for re-heating. That way, the temperature difference between the water and the barrels' walls would stay large, and heat absorption would increase.

Ta Da!


Just need to get the top. We have a huge tree pot we were planning on using and I'm sure it fit but now, for some reason I cannot get it over the barrel. We'll do some creative tweeking and hopefully that will help.

We also wrapped the GH today with the solar cover (heavy bubble wrap). Man, that stuff is heavy! We still have to do the ends tomorrow and some taping but it should help hold in some heat tonight with temps dipping down to 27.

So how has the barrel buried in the ground worked so far? @abhege
I'm trying to have all the ideas that work so, I can work on them while I'm putting up my greenhouse.

Lucky, I just knew someone would ask that! I'm not really sure because we also added the solar blanket to the outside. The greenhouse has been at a consistent 45-47 during the night but that is still with a small quartz heater set at 45. I will say, last year, even with the heater, temps would dip into the 30s so either it's the solar blanket or the barrel, or both.

lol, I saw that you put a solar blanket on it.
How much are those? Did you bubble wrap as well?

The solar blanket is basically a large, heavy duty bubble wrap. Really heavy! LOL!

Off the top of my head, I cannot remember how much it was. I think I got the 20x40 but I'm not sure. Seems like it was under $200. Should make that up in savings on electric heat.

20X40.... wow that is big.
Well, that's down the road for me I guess.
Still thinking about the barrel in the ground idea. Don't want to take up to much room for a barrel in the ground.
I guess I'll think about it as I probably have one more month depending on El Nino

I think my clear 12x24' 5 year solar blanket cost me $80 to 90, free shipping and saved @ least 1/3 of my heating bill, evened temps, and increased humidity. So a investment.

It definitely evened the temps and that alone makes it worth it. Mine was free shipping as well.

@Eric4home Is your solar blanket over the outside of your greenhouse? We have winds of 40 to 50mph frequently on our hilltop so would it work if I put one inside? Our heating bill isn't bad right now because the electric heater only runs during the night. I'd love to be able to raise the temps more than the 55 I have now.

Yes Karen, my cover is on the outside. Since my 1 wall is solid i started at the gutter and I used a 1x1" strip of wood in the gutter to start the rest has a metal strip screwed to the outside edge of the gable rafters and uprights over the edge of the solar cover. I used a wood strip to attach at ground level. Since the entire edge is held down the wind has not been an issue, with gust up to 50-60 mph.

luckyzl230 said:20X40.... wow that is big.
Well, that's down the road for me I guess.
Still thinking about the barrel in the ground idea. Don't want to take up to much room for a barrel in the ground.
I guess I'll think about it as I probably have one more month depending on El Nino

You could always put two barrels in the ground and put a top on them and put plants on the table.