Bone Meal

Bone meal is a material made from crafting bones. It can be used as dye as well as a fertilizer for most plants.

Fertilizer

 * Seeds, Potatoes, Carrots: When applied to the plant, it will accelerate its growth, either moving it to the next stage of growth or final stage depending on its current growth and amount of bone meal used.
 * Melon and Pumpkin Seeds: When applied to the planted stem, the stem will grow to a later stage of development, and enough bone meal can grow a stem to full size. Bone meal only affects the stem itself; melons and pumpkins sprout from adult stems at a fixed rate which cannot be modified.
 * Saplings: When applied, the sapling may grow instantly into a tree, provided it has enough space, light, and luck. Multiple uses of bone meal are necessary to achieve this.
 * Grass Blocks: When applied to a grass block, tall grass, and usually a few flowers, form in a random pattern in a 10×10 area centered on the northwest corner of the grass block (the corner with the lowest X and Z values). This can be an effective method of gathering wheat seeds. The flowers that appear are dependent on the biome, meaning that in order to obtain specific flowers, the player must travel to biomes where the flowers are found naturally. See flowers for more information.
 * Mushrooms: When applied to a mushroom that is planted on dirt, it will eventually grow into a huge mushroom after enough uses. The sudden growth may cause nearby players to take suffocation damage if they occupy the space it needs to grow.
 * Cocoa: When applied to planted cocoa plants, the cocoa plant grows instantly, ready to be harvested for cocoa beans.
 * Sugar Canes: On the Pocket Edition only, bone meal grows sugar cane to maximum height (three blocks tall).

Bone meal does not work on cacti, vines or Nether Wart.

Video
Note This video is outdated, as it shows bone meal as it worked before it was changed in 1.5.

Trivia

 * Tall grass planted with bone meal in an area already populated with grass blocks can force grass to appear up to 6 blocks away from where you originally used it. The chance of any plant growing on the block decreases with distance from the block which bone meal was used on, the chance becoming very small at 6 blocks distance.
 * Bone meal can be used on the sides or bottom of a grass block, as well as on a grass block with plants already on top of it.
 * Regardless of if it succeeds in fertilizing, bone meal makes green sparkles. However, like smoke from a torch, the sparkles only appear if the player has particles set All or Decreased.