Thanks for the tip. Im about to build a temporary pvc greenhouse structure that i can put over the plants to hopefully up the humidity and trap some temp in over night.
Yeah its not a miracle worker and you might have to have alot of barrels to make in impact - I havent really looked into it it.
But Guys who have tried just a few barrels didnt get stella results.
Theres some other weird way to create a heat sink but it involves alot of digging and pipes.
But as I said its not my area of expertise- Google heat sinks for green house - before taking anything I've said on board