Hi Jendle66 - You can harvest hard shell gourds when the stem to them dies back at least a foot. If your gourds are mature, frost is not supposed to hurt them. If they are not mature, frost will do a number on them. However, if they are not mature by the time freezing weather hits, and you take them inside early, they probably will rot. I accidentaly left two gourds outside all winter last year and when I found them in the spring, they were fine. However, our winters here usually only get down to 0. Some growers leave their gourds out all winter, through snow and all. I don't like to because I end up with a lot of dark brown stains which I don't care for. Hope this helps you. Gene