I use a heating mat-roll" (actually a plastic 11-wide heating roll). They come in various lengths (from 3-ft to 20-ft in length). The temperature is regulated by a thermostat. Just roll it out and set as many containers on the roll as one wants. During the winter I keep the containers at a minimum of 64F. Works great. The rolls are water proof, therefore no problem with watering the containers throughout the winter, doesn't matter if they get wet or not, therefore there is no shock worries. They can be regulated to supply heat from 40F to 110F. - Millet (635-)

Which heat mats are you getting that go to 110F? All I've seen are the seedling heat mats that don't really go beyond 76F or so. I've heard about the mats that have thermostats but didn't know they went above 80F . . .


What about my question about the watering with the old nutrient solution?

thanks,
Todd

I feel guilty for not keeping up on this. Got busy at work, but also distracted finishing my greenhouse!

I've not conpletely given up on a networked heated container solution, however, i do think there are advantages to having them sit on a heated mat (or in my case, a heat rope with a few coils under each pot).

Bottom line with heat mats:
We lose the efficiency of concentrating the heat into just the pot, but likely gain the advantage of more of that heat "leaking" up into the canopy area of the plants - especially useful in colder times in an otherwise unheated greenhouse. It's really not a total efficiency loss.

I think Millet and I use the same black and green heat mat. He's right... you unroll it, and optionally hook it up to a thermostat controller. It is made by hydrofarm. They come in various sizes. mine are 20x48 each, and have no problem getting my roots up to 86 degrees! I read surface temps or the mat itself at 110 if unregulated. they are indeed waterproof and durable. I have a 16x48 tray on top of each mat with 3 or 4 potted trees in each tray. one is even suspended above the ground and the heating mat is largely exposed on the bottom thus losing a lot of heat. It still keeps the roots at 80, and if i added an insulator underneath the temps would be even higher. I could not be more pleased with the solution...
Here is a link
http://www.hydrofarm.com/pb_detail.php?itemid=3351
Al

I will say it took 3 full days to get the temps up and stable. initially, i too was not impressed with the mat. Then I realized it was like a pot on a stove. Once up to temp, it takes very little to keep it staying hot ....Also, i think the larger mats are capable of higher heat than the smaller ones. not just larger heating area...

Al