Minecraft wiki entry for Cactus, associated text: Cacti naturally occur in desert and badlands biomes (twice more common in desert than in badlands). They generate as one (11⁄18 chance), two (5⁄18 chance), or three (2⁄18 chance) blocks tall. Rarely taller cacti can be found if generation chooses to generate another on top of one already generated (although not as commonly as sugar cane).