This is my first year with a green house. Most of the plants I will have in it will be fairly hardy down to 32 degrees but on those nites that hit 25 or below ( not many where I am) I need some supplemental heat. I am thinking of using a bullet kerosene heater and or one or two of the 20,000 btu wick type kerosene heaters that you can get at the big box stores. Will any fumes given off hurt my plants? Does any one have any suggestions for alternatives? I do not want to invest in a regular propane green house heater - too expensive and it wont be used that much either. Thank you. ps the hoop house is 26 feet by 48 feet.