Growing plants in the Rockies Greenhouse gardening at 8500ft

As a way to cheaply keeps the plants roots from freezing and keep the soil warm, I came across an article on using a ropelight to warm the soil.

The rope light uses just 5 watts of power, is totally waterproof and is flexible. We leave it on 24/7, the soil temp in punnets for seedlings stays at 70 F, and we fed it thru some planter boxes to help keep he soil warm, so far it seems to work.

Have a look: