Hello
My name is Ryan and I live in Central Michigan where we have what I would say to be mild winters. I built a 10' x 16' greenhouse with "3/8 plexiglass sheets and double walled with plastic. The ground however i dug down 3' and dug 13 yards of material out then insulated with "8 of poly iso foam insulation on floor and walls makeing a tub with an r value of 44. Then refilled with 12 yard of Morgans Dairy Doo compost top soil. Now I heat via hydronic threw pex lines through the floor. I can heat the soil to water I what and would like to keep as warm as possible without killing plants so what would be okay in the winter as far as root temps? By the way I've heated the soil to over 90 degrees before very easily. Below are pics
