sherwindu said:

I have been growing Musquee De Provence Squash this year here in a
Chicago suburb. It really put out a lot of runners and took over most of
my raised bed. Although I may not get much of crop from the many
blossoms appearing this late in the year, I have two squashes of
reasonable size. One got to the size of a basketball,and the other is still
enlarging. It has remained in what I guess is it's maximum size for
several weeks, and is not changing color like the acorn squashes I see in
the supermarkets, with yellow streaking. Question is how to know when
to pick these things? Do they have to do some ripening on the vine for
maximum flavor?

Yes, they have to do as much ripening on the vine as the season allows for
best flavor. Don't harvest until the vines are completely dead. If light
frost threatens, you can cover the squashes with an old towel or with
newspapers, but definitely pull them if a hard frost or freeze threatens.

This variety looks to be in the butternut family (based on the stem as seen
in the photos on the websites I checked). It should do some color-changing
to a deep orange-tan, though perhaps will remain streaked with green.
The stem will become extremely hard, like the hardest of woods, and the
rinds will become too tough to pierce with a fingernail. This variety might
show a frosty 'bloom' on the rind as it matures (based on similar varieties
that I've grown).

When you harvest them, you should (ideally) let them cure in a warm,
sunny location. If you plant to store the squash for any length of time,
wash them in a dilute bleach solution and dry them carefully. Set them
in the coolest area of your house (but not somewhere that might get
below 50 degrees). Leave air space around each squash. Properly ripe
butternut squashes should store for several months like this. The only
danger is a little shrinking from moisture loss.

--
Pat in Plymouth MI ('someplace.net' is comcast)

Any technology distinguishable from magic is insufficiently advanced.
(attributed to Don Marti)