I've kept pumpkins for up nine months before, but nowadays, I just want my pumpkins to last from the time I get them in September or October until the end of November. To keep my pumpkins looking nice and fresh and new throughout the season, this is what I do.
- I'm careful to pick pumpkins with no soft spots, blemishes on the skin, gouges, or mold at the base of the stem or on the bottom. You really have to check them carefully. So many, especially ones from the grocery store, are damaged and aren't going to last.
- When I get them home I wash them thoroughly in the sink or tub to get off any dirt and to wash away any mold spores and excess bacteria. The mold and bacteria are what causes the pumpkins to soften and rot.
- Make sure they are very, very dry. I dry them with a towel and then let them sit on my cold stove burners for a few hours so air can circulate underneath the pumpkins. (You could also use cooling racks, like for baking.)
- When I'm sure they're clean and dry, I take it a step further and wipe them down with either rubbing alcohol, hydrogen peroxide, or a bleach solution. This ensures you're really killing the bacteria and mold spores. Be sure you clean the bottom of the pumpkin and the base of the stem very well.
- Let it dry again. This shouldn't take as long as before. Then you're ready to display them in a cool (room temperature is fine, but try to avoid keeping them right under your heating vents or near your radiator or fireplace) dry place.
- I rarely carve pumpkins anymore, but if you do carve them, be aware that they'll only last a day or two at the very most.
It sounds like a lot of steps, but they go by quickly. It actually takes less hands on time than arranging grocery store flowers in a vase and then you don't have to think about your decorations for three months, so it's totally worth it. That totally works for me.