I probably don't know enough to even answer your question. Just wanted to add that I planted a buttercup (is sugar bon a buttercup??) and only got 8 squash out of about 6 vines. Doesn't seem worth the effort. Am anxious to hear what others have to say.
We were short on rain too, but I did keep them watered.

I'm not sure why that would happen, though I have not grown buttercup before. Buttercup is from the family c. maxima, which is more susceptable to borers than butternut. Butternut is in the c. moschata family.

You mentioned purchasing plants. Why not get seeds during the winter and plant those? Squash is very easy to grow from seed. Just prepare your soil, so that it is weed free (or nearly so) and plant the seeds about 1" deep. It will take about a week for them to come up, but my guess is that squash planted from seed will grow as well or better than transplants, since there will be no transplant shock.

Did you see pollinators on the flowers? I suspect you live in the Midwest. Some parts of the Midwest have been hard hit for pollinators.

Below is a link to thread on hand pollination of squash. It's aimed at producing pure seed. But the technique would work for simply getting fruit. One could simply skip taping the flowers shut.

George
Tahlequah, OK

Here is a link that might be useful: Hand pollination of Squash

Quite a few people had problems this year. We had a late frost and a cool summer which isn't conducive to grow winter squashes. That on top of pests such as cucumber beetles, squash bugs, and squash vine borers and thrown in a lack of bees and some powdery mildew, you'll have a poor crop of squash.

Powdery mildew is always my nemesis and I only fight the initial outbreak, then just watch the whole plant be consumed eventually (although it never seems to affect the squash quality).

Yield can always be increased by hand-pollination of the female squash flowers. Just find a mature flower anther/stamen and sprinkle the pollen towards the stigmas/ovaries.

Um, most of the factors mentioned above could be somewhat responsible. In my experience, the main reasons for poor yields on squash are drought, crowding, and poor site -- bad soil/not enough sun.

But, just so you know for future reference, butternuts are real champs when it comes to production, while the C. maximas are typically more "stingy" when it comes to overall production.

What an interesting read. For me the problem is just opposite. I always get a reliable bumper crop of buttercup, with butternut being iffy every year....yield is okay, but nothing spectacular. We don't (I'm touching wood when I say this)have the squash borers here....our season should be long enough for both, but always buttercup wins the race.

I'd like to "second" what Flora2b has to say. Burgess Buttercup makes a repeat performance yearly in my garden. I've tried other c. maxima like the kabochas with very, very limited success. I think the problem may be an exposed gardensite and cool overnight temperatures.

So, why don't I grow a short-season acorn squash? They just don't taste right coming from my garden. I've tried 3 or 4 varieties.

Early Butternut has grown with good results. And, my DW decided that 'o8 should be a butternut year. I advised her that the Waltham wouldn't grow as well as the Early. She took no notice of what I said and bought the Waltham seed and, sure enuf, it didn't produce very well, at all. I actually thought that the vines had died during a very cool Spring.

Burgess Buttercups overran the butternut hill and produced reasonably well again this year, despite the cool Spring.

Steve