Japanese Black Pumpking Plants (12) with over 25 feet long vines and not one single flower in any of them.

Question

Greetings,
I planted Japanese Black Pumpkin seeds on April 5th. The plants are big, some of the vines are over 25 feet long, but we do not have one single flower in any of the plants (12 plants). I sprayed on June 18 Phosphate/Potash (0.10.10) on the leaves at a rate of two tablespoons per gallon. The PH of the soil is 7. We still do not have any flowers growing. How long should I wait before I give up and take the plants out?
Please advise.
Do you have any explanation/remedy?
I would appreciate any help.
Jose

Answer 1

This article will help you pinpoint the issues and how to correct.

https://www.gardeningknowhow.com/edible/vegetables/pumpkin/pumpkin-plant-not-flowering.htm