My tomato and cuccumber vines are full of healthy looking yellow blooms. Some have turned into fruit...but there's lots of blooms still waiting to be pollinated.
I've learned a little about these plants and I'll try to write down the process in which they pollinate. These plants have both male and female parts and each vine has both...separate from each other, thus resulting in "self pollination". As the pollen is formed and dusted off onto the wings/bodies of insects, usually bees, it is carried to the blooms of the opposite sex where it, hopefully, gets dusted onto it's ovaries. Only then can the bloom grow into fruit.
Now...if a person waters too much the pollen becomes gummy and will be less prone to dust off onto insect wings and be carried to the opposite sex blooms to complete the pollination process. What is too much watering? Good question! Bees are more active in the heat of the day so either water in early morning or late evening. Of course, too much watering causes the roots to not develope properly and only grow shallow...thus leaving plants with a weak root system.