Butternut squash - why are my female flowers shriveling up / not becoming fruit?

[emcas]

I've grown summer squash and zucchini prior but not winter squash; I have two butternut plants (I call them Marcia & Jan - Marcia is doing ok but Jan just grows runners and complains) where female flowers will come in, I hand-pollinate them to be sure they get pollinated, but half the time they don't become squash. They turn brown and shrivel and die off. At this point my yield will be a staggering .. 3 squash. Then, despite pruning back her runners, Jan never produces ANY flowers. It's super odd.

They are in raised beds with new soil having been installed this year; they have leaves for mulch. I fertilized with fish emulsion and then with a high phosphorous content fertilizer but neither seemed to do anything. I am watering almost daily. I am in zone 7.

What am I doing wrong?

 

[YumYum]

I get several unpollinated squash (yellow summer & butternut winter) just about everytime when they first start flowering out. Then it just seems to straighten itself out. I don't hand pollinate but I do notice the bees are more interested in the white clover in the yard than anything to do with any of my cucurbits.

If you are pruning back the runners, you are definitely cutting back on the amount of flowers (male or female) produced at a single time.

 

[emcas]

I appreciate your reply!

So, is this just the way it goes sometimes? Weather has been very unpredictable but I've never not had a hand-pollinated squash not, well, be pollinated. If it were early on I might feel a little less disappointed but ... I'm running out of time to get any more fruit fully ripened.

On my end, it took awhile before any female flowers would come in...but I've had male flowers for most of the summer. My sugar pumpkins also refuse to grow female flowers (I have exactly one pumpkin.) I also have TONS of bees - there are always a few in each flower.

I also pruned back the one plant to try to encourage her to grow flowers, as despite being 40' long, there were (and continue to be) none. Is there a better way to encourage flower growth?