I like the heating method. We put in a radiant floor in a kitchen once. Small pump
recycled hot water from the hot water tank.
Considered a few runs of the heated outdoor floor mats one bad winter a few yrs ago.
Just plugs into an outlet.
Outside the garden we have a big coil of black water tubing on a full sun rock
outcropping. Also hooked up to an outdoor shower. Gets really hot, almost too hot for
a shower some days. Gravity fed to a soaker hose for the grapes and just outside the
main tomato bed. As long as the valve is shut during the heat of the day, a good long
shower, then shut off for the rest of the day, warm water for the garden.
But you will need some sun,
Still trying to figure out NFLD. It is April-June that needs some warmth for the head
start.
I've been using the bean test this year. I would use the poo. After testing with beans
or better, sacrifice a tom seedling.