Minecraft wiki entry for Sugar_Cane, associated text: Sugar cane can generate naturally near water, as two (11⁄18 chance), three (5⁄18 chance), or four (2⁄18 chance) blocks tall. Rare taller sugar canes can be found if the world generator places two smaller canes on top of each other. It generates in approximately 0.8 sugar cane per chunk seeing as how they only generate near bodies of water.