When harvesting pumpkins the stems should be cut so you have a 4 or 5 inch stem if possible. Pumpkins without stems do not store well, so it's important to pick them up from the bottom not by the stem.

Pumpkins should be harvested when mature and the rind is hard, but before night temperatures fall below 40 degrees. Don't harvest when the pumpkins are wet or allow them to become wet after harvesting. Any of these things will cause them to rot more quickly. After harvesting, allow the pumpkins to "cure" if possible. This is where they sit for 10 days or so in a temperature around 80 degrees and a high humidity of 80%. This can sometimes be done in the field if it's warm enough, or near a furnace. The pumpkins will last longer if cured first.

Afterwards, store them at 50-55 degrees in a location where the humidity is about 50-70% such as a basement or a garage. Don't store the pumpkins near apples or allow them to sit directly on a concrete floor.