What about a 30ft long water balloon/bolster/row warmer

[decherdt]

I suppose I may have just lost my last marble but I wonder if a 30 ft long surgical tubing water ballon would just explode, or hold heat for a month of cold nights? Or a large OD drip tape/no drippers? Drag/hoe a shallow trench, roll it out and hook up the hose, open and close a valve......Anyone have a favorite tubing or tape?

[Doug9345]

What I understand is that your are proposing to bury a small diameter length of tubing using it as a tank. Short version is there is not enough mass to affect heat retention of the soil to any degree that you can measure.

[Wi-sunflower]

I do use 2 inch layflat tubing in a 15 ft wide greenhouse for my heat. It is connected to a wood water stove tho and the water in the circulating lines can be close to 200* at times. Basically I use it as a "radiator" type of system. The green house is really more of a cold frame too as it's just 1 layer of plastic. It has kept plants from damage in the 20s but I don't think we've had any tamps lower than that.

Carol

[decherdt]

Thanks Thats more like what I would need. I see that 4" or 6" dia is available. ( the bigger better AG rated stuff seems to be only sold by the pallet) Now I need to figure if 40 gallons in 30 ft of layflat warms a low tunnel better than 60 ft of soil heat cable.

[Doug9345]

I still haven't figured out if you are just going to use it as a thermo mass or are you proposing to heat your tunnel? You are forgetting that the soil itself has a large thermo mass.