Our low tonight is supposed to be 39 degrees. I have my tomatoes in WOWs however today is overcast and cool with a high of 66, so inside the WOWs it is not all that warm. The temp dips to the low 40s around midnight, so it will be pretty cool all night long.

I was thinking of going out this evening and filling the cells of the walls o water with warm/hot water to help keep the plants warmer. Does this sound necessary or like a good/bad idea?