The problem with squash, cukes and other curcurbit producing flowers but no fruit can usually be traced to water washing the pollen out of the flowers before bees and other pollinators can pollinate the flower. If the pollen is washed out of the flower before pollination, the plant aborts the useless flower and puts its energy into producing another fresh flower. Rain can be the culprit but usually it is the gardener him/herself that is causing the problem by spray watering their garden. Remove all LAWN sprinklers from the garden and get a watering wand so you can soak the soil at the base of the plant without getting the flowers and leaves wet. You can also get those black soaker hoses that lets the water ooze out without wetting the plants. Spray watering not only washes off the pollen but wetting the leaves with cold water shocks (weakens)the plant and creates the perfect environment for fungal disease to take hold. There is no good reason to spray water your vegetable garden or flower beds unless you enjoy mushy flowers and vegetable plants that struggle to produce fruit. You can wait until frost kills the plant to harvest your potato crop. If you want ‘new potatoes’ you can harvest them from mid to late summer. I leave mine until frost so they can get as large as possible. You wouldn’t think that home grown potatoes would taste so much better than store bought but they really are…that’s why we grow them every year.