I wonder if the root zone needs the warmth too, or if its just the aerial parts of the plant that needs the warmth for optimal growth. Maybe plastic with holes

I wonder if the root zone needs the warmth too, or if its just the aerial parts of the plant that needs the warmth for optimal growth. Maybe plastic with holes for each stem could be used to insulate the aerial airspace from the root airspace and then a small heatpump could make that 10F differential with relatively low power cost.