Heat for seedlings?

I'm germinating my first seed aright now in Rockwool cubes and they are cold to the touch. The air around them is 78F with a heater. Should I just turn the heater up and point it directly at them, add a light, or is cold Rockwool ok?

Seedlings like warmer temps. I do killer with 80F+. Crank the heater up, but don't point directly at em. Don't wanna dry em out. Keep em misted and under a dome if possible.

I went to school and they must've been cold for 7 hours- do you think they could be dead?

I put a piece of Tupperware over them as a dome.

Doubtful. Rockwool holds quite a bit of moisture - even when they feel dry to the touch.

No they're wet and have been wet. Could they have died from the cubes being cold?

I doubt it. Seedlings don't need much water. If they look dead, it's probably from over watering. Pics would help.

Post a pic plz ty

I misted inside the Tupperware cover and cranked the heat up. Air is 85F with 32% humidity. The Rockwool is room temp now. Thanks guys.
I would post a pic but you wouldn't be able to tell anything from it.