I'm impressed. What zone are you in? No greenhouse now but I always am interested in how others manage them.

I'm in about zone 6b now. When I originally moved here 22 yrs ago this was zone 5, but winters have been getting increasingly warmer for the past 8-10 yrs. We have a southeasterly exposure to our house and gardens, up on a hillside, with "Tick Ridge" behind us to the North, so the North wind dosn't hit us directly, just the tall treetops. Strong

I used to, but haven't really bothered the last few years. This past winter we moved to a new house and now have a couple acres to play with, this year I planted a ton of various cover crops for compost and ground breaking after having just a medium sized garden last year. I am getting serious spring fever now though and think ill start up some cold hardy stuff inside and see what I can keep going into the spring.

Fayetteville is the location (technically Farmington...)

Impressive! I'd never heard of using heat sinks. Are the tubs above ground or sunk down? Sounds like a good use for those big plastic feeder tubs that are used for cattle if they're big enough.

yes, I am using those same syrup tubs in the larger hoops, and various gallon or two gallon jugs in the smaller cloches. In my larger coldframes, 4 of them, I use the excess crystal rocks I have on this property [small boulders] dumped in a plastic covered "L" in front of the coldframe. The rocks heat up faster and hold heat longer than water does, in fact, when the outside temps reach 70 degs I have to cover that rock area or it'll get so hot it starts to melt the plastic overhead. Strongeagle

i did this for many years in an unheated walk-in cold frame while living in the buffalo river area...using in-ground beds and plenty of dry oak leaves for insulation on cold nights. there is something that can be grown 12 months of the year in the ozarks, how wonderful!