Minecraft wiki entry for Glow_lichen_farming, associated text: Glow lichen can fertilized with bone meal manually or via a dispenser. It can only be harvested via shears and if broken with other tools, even enchanted with Silk Touch, the lichen drops nothing. Efficiency does not affect breaking speed. By applying bone meal to one lichen, it is possible to cover the sides and the top of an adjacent block, but not the back. Otherwise, glow lichen does not spread naturally.