I have a late sprouted tomato that has survived cold weather (down to 14 C, hail) for some time. All other tomatoes are near death or long gone. This one is green and vibrant. It sprouted in a bunch of lillies. Lillies have a mechanism called thermogenesis - they create heat. This occurs in the flowers at night. Some insects like bumblebees harbor in the flowers which close over, and are released the next morning, coated in pollen, to do the lillies bidding. I suspect the thermogenesis of the lillies, coupled with the nutrient dense (drain overflow) habitat is providing a nice wee microclimate, and at night, it's enough to make a difference. I don't expect the plant to fruit before the cold really gets here, but I'll watch closely. I do think I may have stumbled on nature teaching us a new trick. Next year I'll put a couple of tomatoes in with the lillies and see if they'll extend the fruiting season.