Melon Seeds

Plant these in the summer. Takes 12 days to mature.
Overview
Melon Seeds are a type of seed that grows into melons when planted and mature. Like other crop seeds, they are a basic farming item used to start a melon crop for later harvest.
They can be purchased at Pierre's General Store, JojaMart, and the Magic Shop Boat at the Night Market on Winter 16. They also appear occasionally in the Traveling Cart. After donating 10 items to the Museum, 

Other sources of Melon Seeds are more situational. Five to twenty Melon Seeds may occasionally be found in treasure rooms in the Skull Cavern. Because of this, players exploring the mines may sometimes come away with a sizeable stack without buying any. On Ginger Island, 
- A planted seed grows into a
Melon crop at maturity.
- Purchase sources include
Pierre's General Store, JojaMart, the Traveling Cart, and the Magic Shop Boat at the Night Market on Winter 16.
- Gunther rewards nine seeds after 10 museum donations.
- The Seed Maker can generate more Melon Seeds from harvested produce.
- Skull Cavern treasure rooms can contain 5 to 20 seeds.
- Mixed Seeds on Ginger Island can sometimes grow into melon plants.
Melon Seeds are especially useful for players who want to scale up melon production efficiently, since they can be bought in bulk when available and also recovered through farming and dungeon rewards.
Official description
Plant these in the summer. Takes 12 days to mature.