The Melon is a Vanilla Minecraft crop which is a block and an item. When eaten it restores two hunger points (1 Shank). Melons grow in Jungle Biomes which when broken and placed in a crafting grid will provide seeds. Melon Seeds can be found in Abandoned Mineshafts and Strongholds and can be purchased through the Market.
1.8 or newer - Melons are NOT found in Gardens.
1.7 or older - Melons were found in Tropical Gardens.
To learn more about the Melon in vanilla Minecraft, read here: Official Minecraft Wiki - Melon
When a Melon seed is placed, it becomes a melon vine block. You do not harvest the melon vine. Once the melon vine is full grown, every 1-30 minutes (real time), a melon block will spawn next to the vine. Breaking the melon block will give the melon item. Silk Touch is needed to pick up the whole melon block.
Melon can be combined with other ingredients to create: