Melon Seeds

Melon seeds are an item that can be used to grow melon plants.

Natural generation
Melon seeds can be found in minecart with chests of abandoned mine shafts in stacks of 2 to 4.

Melon stems
Melon stems, when destroyed, may drop 0-3 melon seeds.

Nether reactor
In Pocket Edition, melon seeds are only obtainable through the Nether Reactor or from crafting.

Farming
Melon seeds can be planted on farmland. Over time, they grow into a stem and produce a melon on any adjacent dirt, grass or farmland block. If a melon is already occupying an adjacent dirt/grass or farmland spot, the stem will 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. Melon seeds are affected by bone meal only with respect to stem growth -- bone meal does not help produce the actual melons.

Melon Stem
The melon stem appears to rise up from the ground as it grows, turning from green to brown. A single stem will connect to any melon in an adjacent square, whether grown there or placed there. If there are multiple melons it can connect to, it will favor the east, then west, north, and south. When the melon is removed, the stem will return to an upright position.