Harvest winter squash when the skin is hard and will not break under thumbnail pressure. Appearance tends to be dull, rather than bright like the summer squash at harvest-time. Spaghetti squash should be a golden yellow. Always harvest before the heavy frosts. Hazards of leaving the fruit on the vine too long include foot-traffic damage, theft, bug, and disease damage.
Leave a 2″ stem on the fruit. Cure at room temperature (70-85 degrees F) for 10+ days before long-term storing begins.
Only put squash that is firm (no soft spots), heavy, and free of blemishes in long-term storage. Store at temperatures from 45-55 degrees, with 50-70% humidity.
Small squashes, like Butternut and Spaghetti, will likely only store 2-3 months. Banana and Hubbard squash will store as long as 5-6 months under ideal conditions.