Winter squash are harvested late summer through fall, then cured or “hardened off” in open air to toughen their exterior. This process ensures the squash will keep for months without refrigeration. When selecting any variety of winter squash, the stem is the best indication of ripeness. Stems should be tan, dry and on some varieties, look fibrous, frayed or corky. Fresh green stems or those leaking sap signal that the squash was harvested before it was completely ripe. Ripe squash has a vivid, saturated color and a matte, rather than glossy, finish.