Hi Gardenerenthusiast,
I am glad you asked this question because the same thing has been happening to me, on both my zucchinis and my spaghetti squashes. Along with rotting blossoms that don't open, I've been getting female blossoms where the squash has shrivelled up before the flower even opens. My plants are otherwise healthy, though I have just started to see some yellowing on the leaves. Unfortunately I have no idea what is causing this, though I've narrowed it down to blossom end rot (which would mean a lack of calcium in the soil) or under watering (it's been very dry here and I've been watering shallowly and regularly, instead of deeply), or some kind of virus/fungus etc. I can't see any trace of pests on my plants, save for a few black aphids, and there are no signs of squash vine borers. One of the strange things is that it suddenly affected my zucchini, spaghetti squashes, and now my delicata squashes all around the same time, even though they are in different garden beds. This makes me think it is either the weather or a virus. My current theory is that I haven't watered them deeply enough, and also that they might need more plant food since they are quite close together and fruiting heavily. Sorry I don't have an answer for you, but I would be curious to know if any of that sounds familiar to you. Good luck!

Thanks for replying Cassiet, yes I too have gotten shrivelled up squash. I was thinking it was blossom-end rot, but why it is happening? Could it also be because there are too many fruits? They're competing for nutrients.

Hmm, I added crushed eggshells to the soil about 2-3 weeks ago for calcium. I also read that it can help deter slugs and snails. Also when my milk is finished instead a rinsing out the bag I just fill it up with water and feed it to my plants for calcium. This can also be used for all types of plants.

Aren't zucchini heavy feeders? Last couple of weeks its been really rainy so I haven't been watering that often. When I do water it is quite heavy, because now it's been pretty humid and sunny. I am watering everyday now.

"they might need more plant food since they are quite close together and fruiting heavily."

Is this usually an indication that more plant food is needed? I mix the plant food in the water, but since it's been quite rainy aside the this past weekend the last time I added plant food was over 3 weeks ago.

I have the same kind of zukes. They have just started.
As I simply compare yours to mine, the buds on yours are TOO pale. The tip of the young buds on mine have nice greenish color. OVERAL, your plant looks pale. Maybe you are watering too much or it is raining too much or it is shaded too much ?!?.

Can you post a picture of the whole plant ? and describe your growing conditions ... temperatures ...

I am having the same (?) problem in NJ.

Just finally got my first full grown squash, after many failed pollination attempts.

Noticed that one of the next female flowers, still days away, the flower had turned brown.

Yesterday morning, some of the leaves looked wilty (around 9:30). Watered.

Last night, around midnight, looked okay.

This morning, 9:15, much of it looked wilty. More of the future female flower buds had turned brown. I picked the first squash, hoping that taking that off the plant would help, and watered.

It was probably already 80-something at 9:15 this morning, didn't check. It is on a ledge running north from the house, in a container, so it gets sun all day long.

This post was edited by bandie528 on Wed, Jul 17, 13 at 13:06

Yeah once the buds started looking a little pale I knew something was wrong. I know what they're suppose to look like, I've gotten three nice zukes already. I don't think it is shaded too much because it gets at least 6 hours of sun. Zukes are heavy feeders so they require regular watering.

This week and a half has been sunny and humid about low 30s but with the humidity it's like 45 degrees. It doesn't cool down at night or in the morning. So I've been watering once a day early in the morning. But before that it's been mostly mid 20s with summer showers every couple of days, not really sunny. I didn't water that often because the rain usually took care of that. But last week there was about over 100 mm of rain in one day. BUT I noticed that there would be a huge growth in the zukes after rainfall.

BUT I NOTICED the buds browning maybe a month ago when my now ripened zukes were still growing. Other than the buds the plant looks pretty green, robust and healthy.

BTW I know one of my plants has a bit of powdery mildew.

'BTW I know one of my plants has a bit of powdery mildew".

................................................................
Are You sure ? PM can spread and almost destroy your squash plants.'

But sometime a grey/silver leaf pattern can be confusing with PM. But anyway, I think you should take the PM problem urgent.

UPDATE

All the buds just shrivelled and dried out and now all the new buds are nice and yellow and healthy looking. They look like they're going blossom in a week or so. I didn't really do anything other than just water it everyday. It's been super humid and sunny. I do not know what happened.

I think Seysonn is correct that does not look like PM I think it is just silver leaf pattern. Does it wipe off?