Should you put a towel under your pumpkins when the weather gets colder?
Would a towel, cardboard, or something under the pumpkins still on the vine help them from growing "warts"?
Certified GKH Gardening Expert
I don't know so much about preventing warts, but it is a good idea to put something under squash that you want to use ornamentally. This helps prevent scratches, scars, rot and other external damage.
A towel or cardboard would not be my first choice because these things will hold onto water which can promote rot. A pile of straw is better at it protects the pumpkin but allows for airflow under the plant and for water to flow away from the pumpkin.