Update: more than two years after my previous post on this thread. All but one of my curry tree plants have died. For a start, none of them grew a very dense root system. I'm not even persuaded that my variety of curry leaf plant has aromatic leaves. I gave up using energy to keep them warm in a heated chamber. Last winter, and so far this summer, the two surviving plants were being grown hydroponically in nutrient solution. But they can't have liked the winter temperatures, down to almost freezing in my house. Not only did the leaves all fall off but the branches fell off, too, leaving simple upright stems, now 4 or 5 years old. I think one of the two plants has now died. The remaining one is growing new branches and leaves fast and there is a new plant growing out the bottom of the pot.