Pumpkins form 2 types of flowers.. males and females.. males develop the pollen and females develop the fruit. You can tell them apart by the baby fruit directly behind the female flowers. Usually they form males a few days to a week before the females. Once the female blossoms start opening, you can start getting pumpkins any time.

If you have a lack of bees, be prepared to hand pollinate by cutting off a male flower, pulling off the petals and brushing the stamen around against the stigma structures inside the female flower (this is best done before 10am). The male and female flowers are only open for a day so you should be diligent.

Depending on your location it may be getting late in the year to successfully grow them before a freeze but in southern regions it's definitely possible.