I have very healthy plants but they are not producing any flowers. There are several reasons for poor flower production. Sun-loving plants when planted in a shaded site often produce few or no flowers. Plants also need to grow and reach a certain size before producing flower buds. Too much nitrogen fertilizer will encourage leafy plant growth, but no flowers will be produced.
Vine crops such as squash, pumpkins and cucumbers produce two type of flowers - male and female.
The male flowers produce pollen but no fruit, only the female flowers produce the desired vegetable. However, you need both types of flowers. Most of the first flowers that are produced are male, with female and male flowers produced within a couple weeks. Plants may produce mostly male flowers if stressed from excessive heat or cool temperatures, or lack of moisture. Vine crops are also insect pollinated so if you don't see bees buzzing around or are using chemicals that may harm pollinating insects, you may not get any squash.