[RJ2019]

Have the plants been getting too cold at night? Also what are you fertilizing them with?

 

[RJ2019]

I have the temperature set to 50 degrees F. I add Miracle Grow to the water every couple of weeks.

That's what I was suspecting. Miracle grow. Back off on the fertilizer, definitely. High nitrogen is contraindicated in tomato plants when they weren't in fast growth phases. A little is fine, a lot causes problems.