I have several zucchini plants in my garden and they all have several male flowers on them, but no female flowers with fruit. In addition, they seem to be turning yellow. They are in a row next to yellow squash, which are green and twice the size of the zucchini and are producing both male and female flowers with fruit that range in size from tiny to 3-4 inches, with many more on the way. If it is a pollination problem, wouldn't it affect the yellow squash also?
Problems With Zucchini Plants
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These articles should help: https://www.gardeningknowhow.com/edible/vegetables/zucchini/solutions-for-common-problems-growing-zucchini.htm