The fruits of my zucchini plants look healthy when only a few inches, and then as they grow start to turn yellow, limp and rot. I have tried adding coffee grounds (diluted) to the soil with hopes that the plant would perk up. No luck. New flowers/fruits still appear fine at first and then seem to drop off. Is there anything I can do at this point in the season to save them?
Problems Growing Zucchini
Certified GKH Gardening Expert
It sounds like you either have a pollination problem or blossom end rot. These articles can help you learn more about both and decide which it might be: