Grown in the "rhubarb triangle" between Leeds, Wakefield and Bradford, Yorkshire Forced Rhubarb is cultivated and harvested indoors by candlelight to preserve its sweet flavor. The triangle offers ideal growing conditions for the 12 Yorkshire rhubarb farmers who still produce the crop. The region benefits from deep, cold and moist topsoil, which rhubarb farmers enhance with recycled-wool fertilizer from local mills. Producing a harvestable crop can take up to three years, as the plant is originally cultivated outdoors to be subjected to frost before being transplanted into darkened sheds that are heated to 122°F (50°C).