Made with 8″ concrete block (laid dry), 2″ thick polystyrene foam insulation, 2×6 pressure treated sill plates, 2-Four fluorescent bulb fixtures(4 feet long), an old sliding patio door, and two 3/8″ rebar for supporting the light fixtures.
I built two of these. One in the open and one in the greenhouse. I started all of my plants outdoors this year. I will try to grow vegetables all year long with these.
My wife is sure relieved to have the fish emulsion smell out of the house!