When should I take my covers off?

I bought some of my plants really early this year and because no spot in my house gets any direct sunlight everything started to look wilty. I talked to a SFG expert who told me I could go ahead and plant my tomatoes and peppers right now as long as I kept the plastic covers on them to protect them. She was right and my plants look awesome and are starting to grow really well--they have been staying nice and warm under the cover. She told me I need to remove the covers during the day when it gets warm so they don't cook when temperatures start to rise but I didn't ask her what kind of temps she was talking about. Today it has been 60 and I pulled a corner to vent it, which seems like it was pretty good--still warm in there but not hot. At what temperature do I need to completely remove the covers so my plants don't die? And what nighttime temps do I need to watch for to put the covers back on?

I'm very happy with my tomatoes--this is the first time I've ever planted them horizontally and it was super scary to bury them so much but the tips have turned and they are growing straight up now!

I have harmed more plants by keeping them too warm than I have too cool. Absent a thermometer, get in your car. Is it warm? Better get the cover off fast. Temps between 40-60 won't kill your tomatoes, but they will slow down the growth for a while. The plants won't exhibit any growth above 85-90 either.

Well, I guess I got my answer today because I waited too long and everything is dead. What a bummer...

Probably too late to add anything immediately useful. Please accept my condolensces to the deceased.

I noticed that hoops/covers run about 40 degrees above outside temps on sunny days...as a rule of thumb. They run about 10 degrees above on cloudy days. And, the temps spike really quick when the sun pops out from clouds.

Managing hoops isn't easy. And, it isn't likely easy for someone that works a full day away from home.

My recommedation going forward would be to vent your hoops on cool days by popping a corner or rolling halfway up the sides when temps are supposed to be in the forties on sunny days. If it's supposed to get above 50, just open them up all the way.

On cloudy days, I would not worry unless things are going to get to 60. But, on partly cloudy days, I would err on the side of too cool.

At night, I would cover tomatoes on any night getting down to 40 or below.

Hope that helps attempt #2.