Question about temperature

ok I am growing in my camper in the backyard.. I have the whole Grow set up in the closet.. I'm in southern Ohio so it's pretty cold temperatures right now..

I have a thermometer, It has a base that shows the temps and humidity and there's a secondary device that's meant for "outside" that sends the reading to the base. I have the secondary device inside of the pot with the plant. Here's a pic just to explain what I'm talking about:


My question is:
If the one inside the pot says it's 75degrees and the one that's sitting below the pot is 60degrees, is that good enough? You would think not becuz the roots are obviously cold cuz they aren't getting the light from the bulbs. I have a heater inside the closet but it's lowest thermostat setting is 65 but sometimes it makes the temp in the pot up around 80-85degrees.

I'm looking at everything here becuz I'm having major problems with this damn plant. I've got new soil mixed with perlite so hopefully it helps and I just started adjusting ph of the water I give it so fingers crossed.

I would think an electric blanket would be better than the heater for the root zone

Your root zone temps are fine. I have a rum and whiskey strongbox that is dug about a foot into the ground outdoors. In the heat of summer it does not go above 60 degrees. Just the way it is, soil is cooler.

i thought about growing in my travel trailer, in the bathroom,,
are you venting out,, or recirculating the air?,,
can you heat up the camper,, as a whole?

lol@ spotlight