Plant is large, looks healthy, blossoms galore, zucchini start to about 3 inches, then shrivel. Growing organically, treated for white flies, aphids, no visible creatures; bees and butterflies in my garden.
It sounds like a pollination problem. Even if you see pollinators in the area, wtih the heat as it's been in much of the country and heavy rains in some areas, pollination becomes more difficult. When this happens, it usually helps to hand pollinate plants.These articles will help:
https://www.gardeningknowhow.com/garden-how-to/beneficial/insect-pollination-process.htm
https://www.gardeningknowhow.com/edible/vegetables/squash/squash-fruit-falling-off-the-plant.htm
https://www.gardeningknowhow.com/edible/vegetables/squash/pollinate-squash-by-hand.htm
What causes bumpiness on the surface of zucchini and does it affect edibility?
Typically, these are caused by damage that the fruit suffered when it was small. It does not affect the fruit in any way that would make it harmful to you.
Our zucchini plants produced only one zucchini this year in July. The zucchini grew to approximately 8 inches; however, it never ripened and has remained extremely hard. What may be wrong? As well, lots of flowers but no more zucchini formed. Is it possible to only have male flowers all season or no pollination? Any other possible reason for no fruit setting?
Poor pollination could be to blame. Here is an article or two that you may find helpful: https://www.gardeningknowhow.com/edible/vegetables/zucchini/zucchini-fruit-fall-off-the-plant-before-they-are-full-grown.htm
https://www.gardeningknowhow.com/edible/vegetables/zucchini/why-zucchini-blossoms-fall-off-the-plant.htm
This is our first time to grow zucchini. We started late and now have vines growing along our fence and flowers but wonder when to expect zucchinis to grow and what they will look like as they begin.
You should have zucchini by now. You may have a pollination problem. You need to attract more pollinators to the garden. In the meantime, you can try to hand pollinate the blossoms. These articles can help you with both things:
https://www.gardeningknowhow.com/garden-how-to/beneficial/creating-a-pollinator-garden.htm
https://www.gardeningknowhow.com/garden-how-to/beneficial/insect-pollination-process.htm
https://www.gardeningknowhow.com/edible/vegetables/squash/pollinate-squash-by-hand.htm
It sounds like a pollination problem. These articles will help:
https://www.gardeningknowhow.com/garden-how-to/beneficial/insect-pollination-process.htm
https://www.gardeningknowhow.com/edible/vegetables/squash/squash-fruit-falling-off-the-plant.htm
https://www.gardeningknowhow.com/edible/vegetables/squash/pollinate-squash-by-hand.htm
You could also be having a problem with blossom end rot. This article will help if you are seeing any of this as well: https://www.gardeningknowhow.com/edible/vegetables/squash/squash-blossom-end-rot-causes-and-treatment.htm
I have seen some aphids and also green worms on my zucchini. Someone suggested Spinosad and BT for the catterpillars.
BT will only treat the caterpillars, but is a good control for them.
I am not all that familiar with Spinosad as it is relatively new, but from what I have read, it works much like neem oil. The plant absorbs it and when a bug eats the plant, it dies. I neem oil (which would be another option for you) works very well, so I imagine that Spinosad would be as effective.
My zucchini fruit get to about 3 inches long and yellows and falls off the plant. The plant looks relatively healthy other than this. There were numerous fruit but it has happened to every one. The plant is in a raised garden bed with bought soil.
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: https://www.gardeningknowhow.com/edible/vegetables/zucchini/zucchini-fruit-fall-off-the-plant-before-they-are-full-grown.htm
https://www.gardeningknowhow.com/edible/vegetables/squash/squash-blossom-end-rot-causes-and-treatment.htm