Minecraft wiki entry for Melon_Seeds, associated text: Melon seeds can be planted only on farmland. Over time, they grow into a stem and produce a melon on any adjacent dirt, grass block, farmland, podzol or coarse dirt. If a melon is already occupying an adjacent dirt/grass or farmland spot, the stem does not grow any more melons until the melon is removed. A single stem can grow an unlimited number of melons. Like other seeds, they need a certain amount of light to grow and produce melons. Melon seeds are affected by bone meal only with respect to stem growth; bone meal does not help produce the actual melons.