I can't put a blanket over mine, but that's a good idea if you can do it.
I do have foam board that I use between the tent floor and the pots. For my seedling phase in cups I use seedling trays with the dome lids and I cut out holes for the cups to sit in like in a cup holder. and I have the trays on top of laminate floor planks which sit on top of seedling heat mats which sit on 5 gallon bucket to put distance between the tent/garage floor and the plants.
Then I have a couple of electrical heaters in the tent. Right close to the seedlings.
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