That is looking quite consistent with an acorn squash. Stop worrying! It looks like a summer squash cuz a summer squash is simply an immature squash. Most summer squash when left on the vine will eventually get large, seedy and develop a hard shell. The one pictured would probably be a reasonably tasty morsel if harvested now. But wait and your patience will be rewarded.

Hey Carol, My best advice would be to leave them on the vine for a few more weeks. Acorn squash are interesting in that they do eventually turn orange like a pumpkin but they are mature even before that when they are dark green. Basically, as you might or might not know, squashes are divided into two categories. There are "summer squashes" and "winter squashes." Summer squashes include zucchini and are harvested BEFORE they are mature. This allows the flesh to be very soft, squishy, and palatable with little cooking. Also, the seeds are edible at this stage and thus do not need to be removed but may be eaten. Winter squashes however are harvested AFTER they have matured. The flesh is usually harder, must be cooked longer, and the seeds are very hard, mature, and must be removed prior to cooking. This is why we remove pumpkin seeds and in your case, butternut squash seeds and acorn squash seeds. Since acorn squash and butternut squash are both winter squashes, they can be harvested any time after they have matured, giving you a much larger window during which you may pick them. Essentially, it is never too late to harvest a winter squash. By that same token, it IS too late to harvest summer squashes when they have matured unless you want to remove the mature seeds. What this boils down to is that you should wait a few more weeks for your acorn squashes to grow. I've grown acorn squashes for a few years now and they usually are ready by the second week in August but never before the third week of July and my zone is 6. Hopefully that helped! Good luck! Joer

Count on two months. It might be longer, depending on the temperature. If you eat them regularly, you'll notice that their texture will be getting more and more stringy/grainy as they near the end of their shelf life. Acorn squash are not meant to be stored too long. Another idea would be split and bake them, scoop out the flesh and freeze it in ziploc bags. That would last at least two years. George

I haven't grown Acorn squash, but it's fairly common to loose a few of the first summer squash that appear. I've been told that it is due to incomplete pollination, but have also been told that the plants are just new to making fruit and will get better at it. I would keep hand pollinating, it will more than likely be fine.