I wonder If it really makes a difference tho, as tobacco from the feald also has an bunch of spores on it. As long as the temperature is kept above the temperature where mold grows during the curing time, to my mind it seems like it won't actually matter.
I’m going to use a ceramic heater wired to a temperature controller and looking at LED grow light
Done! As of 5 minutes ago I have the led grow light, and the 4” duct fan running with a Govee for tracking installed. I still need to secure the wiring inside and give it another wipe down - it still has a slight ‘old refrigerator smell’. For the record it is starting at 77 degrees but we were back in the 80’s here today.
Is the 4” duct fan just stirring the air inside and doesn’t let any external air in or out? If that is the case, I would install the grill vents so one is on one side near the bottom and one on the opposite side near the top. Then get a simple on/off temperature controller (like an Inkbird) and use the duct fan as an exhaust fan. Hang the duct fan inside at the top of the fridge and plumb the outlet of the fan to the upper grill vent. Leave the vent at the bottom attached to nothing, it is your fresh air intake. let the temp controller drive the exhaust fan and have it turn on when the internal temp is too high. I would also get a small 5 or 6” clip on fan to stir the internal air. Your seedlings will need fresh air (CO2) and can’t be sealed inside a closed box like you do when kilning.
A problem with the simplest temp controllers is that they don't have enough temp hysteresis. However I think I remember that Inkbirds do have min and max heat temps. I wondered why did some plant temp controllers had start and stop temps. I was thinking any old thermostat with a couple of degrees of hysteresis would be adequate. Then I read an article from NC State Extention that stated germinating seeds liked a temp swing between 68 and 86 degrees. The article was for pelleted tobacco seed but it seems loose seed would want the same. So NC State learnt my brain a new wrinkle real quick (the brain being the one place one should enjoy a new wrinkle). So here I was smothering my seeds with love and heat and they did not want it all the time.
When growing plants indoors I always let them have a temp swing. Warmer during the day and cooler at night. Seems more natural to me. The only time I control heat is when the lights are on and things may get too warm. When it’s lights out, the temp swings back down to room temp, which in the winter is 65F at night. During the day with lights on, the temps get close to 87F. I generally keep my humidity constant 24/7. I only grow indoors in the winter when it is easier to control the heat and humidity, plus electricity is cheaper.
