Minecraft wiki entry for Shelters, associated text: Easier to manage but somewhat less useful than the above two projects, farming sugar cane and cactus underground requires little effort. A cactus farm requires sand to grow, and sugar cane needs to be properly irrigated with water within one block of it. If you don't want to spend lots of time harvesting your cactus, place a three-block-tall pillar next to where you want your cactus (See Farming for more info).