As the day warms and the humidity rises the pollen becomes tacky and non-viable. it is most viable within a short time after the blooms open.

Plus you have to beat the bugs to it. :)

Dave

Maybe they aren't a morning sex type of Zucchini! ;)
Personally, I let my Zuk do their own thing and usually end up putting them on the neighbor's porches on Aug 8th "put a zucchini on your neighbor's porch and run" day!
Nancy
PS...That's DH and my 40th anniversary of our first date! Watching Nixon resign!

Lol funny one nancy :)

Thank you digdirt, that's probably exactly what it is. See, I like in Texas so I imagine to heat cause the pollen to be non-useable if I pollinate at 10

Is there some reason you are hand pollinating zucchini?

There can be many reasons for hand-pollinating them. Growing them under cover to prevent SVB is the most common. Stress, lack of active insect pollination, blossom-drop or BER, ratio of M:F blooms, preventing cross-pollination, room for only 1 or 2 plants, etc. are all reasons for hand-pollinating. There is a FAQ here about it.

Dave

It is good to get some started as soon as possible....before the plants die!

I suspected it might be the SVB, but I didn't realize they were a problem for Zucchini as well as other squashes. I haven't grown much squash. Thanks Dave, for that explanation.

I have a sinking feeling I'm going to be hand-pollinating this year since it seems that most everyone's hives in and around Central Ohio got wiped out this past fall/winter from Colony Colapse :^( so that's good to know about doing it early in the mornings. I imagine the same thing would apply to cucumbers? What about bush green beans, or are they self-pollinating?
Edie