Poor Fruiting on Cucumbers, Squash and Other Vine Crops
Start by taking a closer look at the flowers. The first set of flowers produced is all male flowers. The next set of flowers is a mix of male and female. Look for the miniature fruit at the base of the female flower. Now pollination can occur, so the fruit can develop.
Once your plants start producing, you can further increase productivity with proper harvesting. Pick bar type summer squash when it is 6 to 8 inches long. The rinds will be thin, seeds small, and flavor the best. And your plants will keep producing. Harvest cucumbers for sweet pickles when 1 ½ to 2 ½ inches, dill 3 to 4, for slicing 6 to 9 inches long and burpless or Japanese 10 to 12”.
A bit more information: Some newer varieties of cucumber such as General Lee and Olympian, are gynoecious meaning they only produce female flowers. A few male seeds are included to provide needed pollination. Others like Diva are parthenocarpic. These produce all female flowers that do not need pollination for fruit to develop.