Keep the pumpkin cool and dry,
BUT NOT COLD,
they shouldn`t freeze.
They also shouldn`t be leaning against anything or pressed against each other.
Basement or garage as long as it doesn`t go below zero.
If you have a rack or plant stand,
you can put a towel on it and keep the pumpkin on it.
DO NOT FREEZE.
Every one keeps telling people to freeze their pumpkins but that will turn them to mush.
If you`ve already carved it (well,
I once carved a pumpkin a few days before halloween,
like 2 days,
but there was a dent in the pumpkin and it started to rot where the dent was.
Mold spread really fast.
I had to scrape the mold off,
spray the inside and carved area with a bleach and water blend,
let dry and slather it with petroleum Jelly.