Finished the setup with plywood sides, a small 12v vent fan, and reflective floor. During peak sun hours I turn the front reflective wall to the living space to deal with solar heat gain. Fan is on a thermostat, so, during the hottest hours can maintain 84 degrees. When sun is on the way out I turn reflective wall to grow, 25w led grow is running 16/8. Got my routine down. Warming up now so diurnal swings are 55 to 85 instead of 40 to 85. Much easier to germ now, less stress all round. Soon diurnal swings be more like 62 to 85.