what causes zucchini female flowers not to open and then the vegetable rots? I have a small greenhouse.
I don't believe I am over watering, but there are some leaves that seem to have blight or fungus?? One plant has never produced vegetable and the other 2 only 1 zucchini comes to maturity. I believe I also have white flies on a small portion of my tomatoes. It is possible the tomatoes also have a fungus, lower leaves yellow than brown. I have lots of glorious tomatoes so I hope you can help save my plants!! Thank you so much for being there to help! I understand it is hard for you to diagnose without seeing the plants. I live in Pacific Grove, CA 93950. Do you know of anyone that I can hire to help advise. I don't know how to upload photos. Patricia Van Laarhoven
Certified GKH Gardening Expert
Unfortunately, without photos I will be taking guesses. Fortunately, I believe that I know what the most likely two causes could be.
The most common cause that can cause this symptom on both of your plants will be a MAGNESIUM and CALCIUM deficiencies. This will cause what is known as Tomato End Rot, or simply Blossom Rot. It affects many plants and is caused by a lack of calcium (and magnesium, since calcium is almost useless without magnesium)
This can be corrected VERY easily. A handful of DOLOMITIC LIME per container will resolve the issue within a week. You may not notice the correction until new fruits form, though. It won't take a way damage already done.
Another possibility is that it does, in fact, have an infection. This can be treated by adding WETTABLE SULFUR to the Dolomitic lime if the lime treatment doesn't work in a few weeks. You only need a teaspoon or so per pot.
These articles will help: