Melon Seeds

Melon seeds are an item that can be used to grow melon plants. They can be found in Abandoned Mine Shaft Chests, or crafted from melon slices. Melon slices in turn can be obtained by Trading, or by mining a Melon block, which (as of version 1.7) is occasionally found in Jungle Biomes.

As of version 1.7, the various forms of melons are somewhat more difficult to find, as both dungeons and jungles are much rarer. The easiest way to find them is now to purchase the slices from Villagers.

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. When a melon grows on farmland it turns into a regular dirt block. A single stem can grow an unlimited number of melons.

Melon seeds take a longer time to grow than other crops, and breaking a melon block yields 3-7 melon slices which can be used as a reliable food source. Melon blocks only grow when no opaque block is directly above the stem.

Melon seeds, as with other seeds, need a certain amount of light to grow. A Torch seems to be the minimum lighting needed. Redstone Torches or very little light cause the seeds to pop out of the ground and can be picked up again. This allows for semi-automatic farming, This is because when the plants pop out of the ground because of low lighting, they may occasionally return 2 seeds to the planter. Melon Seeds are affected by bone meal only with respect to stem growth -- bone meal does not help produce the actual melons.

Additional information regarding farming melons can be found under Melon Farming.

Pocket Edition
Plant more melons.

Automatic Farming
An automatic melon farm can be created using pistons. Placing melon seeds, empty dirt, and pistons in a particular fashion can ensure that melons grow in front of pistons, so when activated, the pistons break the melons. The melon slices will then be forced forward. By placing a water channel directly in front of the melons, you can build a system that will deliver the melon slices to you by water.

NOTE: If you are creating an automated farm in an enclosed space, such as underground, a melon plant requires a transparent block above it to spawn a melon in an adjacent block. This does not apply to the melon block itself, which will grow normally with a block above it.

Trivia

 * In Minecraft Pocket Edition, melon seeds are only obtainable through the Nether Reactor.