The spacing will depend on the type of pumpkin you are growing. (The 15 plants are all pumpkins, right?) Ideally, follow the suggestions on the seed packet or transplant. In general, mini pumpkins may need about 1.5 to 3 feet between each after thinning, while standard pumpkins need about 3 to 5 feet. In a planter, the giant type of pumpkin likely wouldn’t be appropriate. For standard types in a 3x3 bed, thin out your 15 pumpkin plants to just 1 or 2, snipping the stems off at the soil surface, so as not to disturb the roots of the plant(s) you’d like to keep. For mini pumpkins, you might be able to keep 2 or 3 plants. (For pumpkins, it’s better to have a deeper container, such as 2 to 3 feet deep, if possible.) Good luck!
The spacing will depend on the type of pumpkin you are growing. (The 15 plants are all pumpkins, right?) Ideally, follow the suggestions on the seed packet or transplant. In general, mini pumpkins may need about 1.5 to 3 feet between each after thinning, while standard pumpkins need about 3 to 5 feet. In a planter, the giant type of pumpkin likely wouldn’t be appropriate. For standard types in a 3x3 bed, thin out your 15 pumpkin plants to just 1 or 2, snipping the stems off at the soil surface, so as not to disturb the roots of the plant(s) you’d like to keep. For mini pumpkins, you might be able to keep 2 or 3 plants. (For pumpkins, it’s better to have a deeper container, such as 2 to 3 feet deep, if possible.) Good luck!