Question: How can you tell when pumpkins and winter squash are mature and ready for harvest?

Answer: Harvest pumpkins and winter squashes after they change to their expected color and after their skin is thick enough that a thumbnail doesn't puncture the fruit when you press on it. If you plan on storing the squash, don't let them get hit by frost or they will rot. Also, leave 2 inches of the stem attached for best storing.