I have deep wood container boxes. They are large 8ft by 5ft about. I am in Haliburton. I have planted zuccini two years in a row and get lots of only male flowers. The stem of the plant coming out of the ground is dark green (like a zuccni) and is about 4 inches long….no flower though. I have about 6 hours sun. Again there are lots of male flowers but no female. Netting is over the gatden to keep out animals.
What I have read is that male flowers come first and then when it is consistently warm, like now, female flowers will appear. Male flowers come first to insure an abundance of pollen. Female flowers are larger and require more of the plant’s resources to produce. If the temperatures are too high, the female flowers will abort. Also if the soil is too dry, there will be an abundance of male flowers. Another thing that might help is continually removing the male flowers so the plants continue to produce flowers. Zucchini flowers are good to eat – dip in batter and saute. Yum!