Brent, Bet if they made a cover about 12" over the top of the plant, They might keep them going. #1 problem here was that the forecast for 3 or 4 days in a row was mid 30's to low 40's F, THen about 1/2 hour before sunset they changed it, Not enough time left to do much. Heating with bricks and rocks goes back a day or 2. Bet Doug might remember the old foot warmers, Was a brick or rock that you warmed in the oven and placed in the foot of the bed. Never used one, did see some in a Shaker museum. I am going to try to get some rocks and paint them black to see if they will help in Greenhouse. Trouble is here some times we see -40F or -40C, take your pick. Lord Byron