Recently discussed in this forum.

Here is a link that might be useful: Will butternut squash continue to ripen after picking?

And if they haven't been picked yet just leave them on the vine even tho it may appear to be dead - it isn't.

Dave

Very young winter squash (still light green) can be peeled & eaten much like summer squash, with varying degrees of acceptability... some good, some not so much. Those that have begun to change color can be ripened indoors, but may be more watery & less flavorful that those ripened on the vine.

Squashes which are near full size but not yet changing color are a crap shoot... in my experience, they will generally be inferior quality no matter how they are handled. I would still eat them for sustenance - and eat them first - but not if squashes of better quality were available.

I agree with Digdirt, leave the squashes on the vine as long as possible, even after the first light frost. Most of the leaves may be singed, but ripening will continue as long as the vine itself is still alive. I have observed that the vine may pull nutrients from some of the less mature squashes at this time. If further frosts are expected (low 30's) after the foliage has been nipped, the now unprotected squashes might sustain cold injury, so use best judgement, and cover or harvest if necessary. The squashes should always be harvested when a hard freeze (below freezing) is forecast.

Most winter squashes will begin to sweeten in storage, as starches are converted to sugars. This process starts as soon as the squashes are cut from the vine. Along with the sweetening, the squash may become more watery over time, and fibers in the flesh may become more pronounced. Seeds within the squash also continue to fatten up in storage, so if you are saving seeds, or intend to eat them, then do so 3-4 weeks after harvest.

Personally, I like winter squashes best in the first week or two after harvest, when they are firmer & their starch content is higher. Toward the end of winter, the squash may still technically be "edible", but I often find them to be unpalatable to my taste.