You could harvest them to eat immediately, although the flavor and sweetness won't be fully developed. For storage, you need to leave them on the vine until the shells are hard. Squash picked so young won't keep.

How hard? They are pretty hard, how do you know? How long does the process typically take with acorns?

Winter squash are normally picked only after the vine begins to brown and dry. Regardless of how "hard" they feel, you gain nothing by harvesting them now unless you want it for eating right now. But unless destructive pests are a serious issue, you lose nothing by leaving it on the vine for now and letting it mature more for better flavor and storage.

Dave

Acorn and Delicata squash are sometimes referred to as "Fall Squash". Because they're not summer squash like other Pepos and they're not true winter squashes like the Maximas. The name "Fall Squash" is appropriate given the performance. These squash require no curing for excellent taste early in the season, right after harvest in early Fall. But on the other hand, they don't store quite as long. They seem to be "in-between" the summer and winter varieties.
As far as when to harvest... I have found the quality has peaked (or nearly so) when the yellow spot on the bottom of the squash turns a waxy, orange color. Assuming that you are growing a green and orange variety.

The question is: what would be the advantage of harvesting now, more than for immediate consumption? To store them? Then harvesting now isn't a good idea, because it will shorten storage time.

Is there some other reason?

I was asking because I want to eat them! :)

I would assume picking would also encourage more production.

This post was edited by Peter1142 on Mon, Jul 21, 14 at 14:39

Both good reasons.

Yes, eating sooner is a good reason. I eat my acorns or delicatas much earlier than my Maxima winter squashes. They fill the gap while I'm waiting for my Maximas to reach their best eating quality, which begins around Thanksgiving. And in early March, the Pepos suddenly turn corky and flavorless, while I still have various Maximas still in good shape.
I doubt harvesting will encourage any more production, but that's in my climate where I don't harvest before October 1st.

I put my winter squash, Taybelle acorn and Hi Jinx pumpkin in on June 11th. My garlic harvest was about a month early for all varieties and I have already harvested the pumpkin and am waiting for the acorns as they took longer to put out female flowers and set fruit. I did find, however, that both the acorn and the pumpkin dropped polinated and un-developed female flowers when they had set as many fruit as they could carry. For the pumpkins that was three per vine, one of the acorns has three good sized ones and the others have 4 or 5 each which I expect won't be overly large. Some are very dark green with hard skin and others are still a lighter green and soft. I did break off two of the acorns accidentally and am glad that I can go ahead and eat them. One of the summer squashes I planted, Heirloom Yellow straight neck, did not taste good if harvested too early.

Thanks for all the good information.

I am anxious to get the squash harvested so I can begin to prepare the soil for the main event, garlic.

The ones I harvested tasted great... not really sweet, but I don't think bush acorn squash is supposed to be sweet. Very flavorful and not stringy. And they did make more.. but all my plants had SVB so they are small and not fully matured :(