Sow pumpkins in the garden in spring when all danger of frost has passed, and the soil temperature has reached 65°F, and night air temperatures are above 55°F.

Harvest:
Pick pumpkins when deeply colored–deep orange or golden white–and stems and vines have dried and turned brown. The rind should be hard, not easily penetrated by a fingernail. Thump maturing pumpkins; a ripe pumpkin will sound hollow when thumped.

For more information on growing pumpkins, check out this great guide from Harvest To Table:
https://harvesttotable.com/how_to_grow_pumpkin/