PLants have flowers which fall off and not produce fruit.
-Extreme temperatures, especially in the high tunnels at this time, can cause flower drop. High temperatures interfere with fruit development even with the flowers having been pollinated. -The Zuchini plant needs to have both male and female flowers to open at the same time so that pollination, which is enabled by insects and rarely by wind because of the heavy and sticky nature of the pollen, can take place. Sometimes it helps to hand pollinate. If not pollinated, the flowers fall off. Are there pesticides in your garden? -Flowers may also shrivel and then fall off as they age