Posted: 07/09/2013 at 19:13
Green Magpie, there are a lot of different kinds of Winter squashes with all sorts of shapes and colours and some folk call them all butternuts. If the seed was saved from a squash grown last year, it could be a cross between two different Winter squash varieties and there's no telling what colour or shape it will be. It will still very likely be very good to eat but the taste may not be as good as a pure-bred variety.
Andrew, if they get frosted they are still good to eat but won't keep. You can harvest them and ripen them indoors on a sunny windowsill but they are best ripened on the vine if you can. If the vine is looking the worse for wear and the leaves are already going yellow then you may as well harvest them now as they won't grow any larger with no food coming from the leaves.