I'm making large hoop row covers for some of my raised beds to extend my growing season/winter garden. Looking for best supplier for 6 mil UV greenhouse plastic. I don't need really wide plastic, the hoops are 8' wide so maybe 10' plastic at the most.

Also been researching row hoop covers to see what a double layer with 2" air layer between offers in protection. I've found a couple resources suggest that this set up would provide about 8degrees F of warmth for nighttime. Assuming that is without any passive heat collectors. Does anyone else have information on how much protection this type of row cover offers? Working on a fall/winter planting calendar and sort of need to know for timing of planting. etc.

If you are just needing a small amount of plastic like that, you can get it cut to size at https://www.acfgreenhouses.com... . I have purchased some in the past from them, and it held up fine for me.

If you are are relying on the Sun for heat only, adding insulation to the greenhouse is only going to slow the heat loss during the night. Eventually the greenhouse is going to reach within a few degrees of the outside temperature. A better insulated greenhouse is just going to release the heat from the day a little more slowly.

Another source which I have used for 6 mil UV is Greenhouse Megastore. https://www.greenhousemegastor...

Depending on the size you need and how much you need, shop around, as prices/shipping will vary.

Yeah I wasn't planning on growing tropical plants in the row cover, but there are several crops which could continue to be harvested if conditions are mild enough. The row cover would also keep the snow off the ground. I'm thinking of experimenting with different heat sink materials and possibly seeing if a solar powered heater might be available. The beds are only 4x8 so not much room for a heat sink but also not much area that needs to be heated. From what little I've read so far, appears that water is actually a better heat sink than stone so I might go with five gallon buckets of water and maybe paint the buckets black.

Thanks for the sources. I'll check them both out and maybe look to see if they have any type of solar heat system.

I designed this heat sink system that I used for two years when I was growing all year. I liked it, but removed it (and the raised elevated beds on the left) this past Spring simply because I decided I needed more room. I don't know if you saw this before, but it might give you some ideas...

[quote="MoonShadows"]I designed this heat sink system that I used for two years when I was growing all year. I liked it, but removed it (and the raised elevated beds on the left) this past Spring simply because I decided I needed more room. I don't know if you saw this before, but it might give you some ideas...

I have been thinking of doing something like this with my greenhouse. How much warmer were you able to keep the greenhouse? I have heard this setup will also help keep the greenhouse from heating up as quickly in the summer because it is using some of the heat entering the greenhouse to warm the water during the day. Did you notice anything like that?

@Moonshadows that looks like a nice set up. Unfortunately the idea it gives me is that I need to move to a house that has a larger yard so I can do more. LOL. What did you do with the space where you ripped out the raised beds?

@NCgardening I read the same thing. The heat sync also slows the rate at which the air heats up during the day as the heat is transferred to the water.

I wonder how well an old radiator filled with a salt water solution might work. WOuldn't really have an air stream being forced through the radiator so it might not work all that well.

NCgardening said:[quote="MoonShadows"]I designed this heat sink system that I used for two years when I was growing all year. I liked it, but removed it (and the raised elevated beds on the left) this past Spring simply because I decided I needed more room. I don't know if you saw this before, but it might give you some ideas...

I have been thinking of doing something like this with my greenhouse. How much warmer were you able to keep the greenhouse? I have heard this setup will also help keep the greenhouse from heating up as quickly in the summer because it is using some of the heat entering the greenhouse to warm the water during the day. Did you notice anything like that?

The heat gain during the winter all depended on the outside temp and how much sun there was on any given day. I did have a barrel heat strap attached to one of the barrels that I could use to increase the heat on cloudy or snowy days and on very cold nights. And, yes, I did notice a "cooling" effect during the warmer weather.