Are the buds formed and just not opening, or are flower buds themselves not forming? We ask because fertilizer might help with the latter, but won't with the former. Squash blossoms open up early in the day, and are only open for less than one full day, having been pollinated by specialist squash bees by midday and then closing-up, especially when it's hot out. Plus, male flowers and female flowers appear separately, so flowers that open, close, and never fruit may be male, not female.

Do you have any photo examples to share of blooms that are withering before opening, as if killed by fungal infection or some other factor? Is there a sprinkler wetting-down the plants early in the day, where that might keep the bees from flying and pollinating flowers?

Miri

Thank you for the photos. Although we can't see the symptoms clearly in the pictures, our primary suspect is Choanephora Rot, a common fungus that can kill blossoms or young fruits when the weather is warm and humid.

Remove any failed blossoms promptly so they do not harbor fungi which can spread to other buds, and try to make sure the flowers aren't gotten wet when watering the plant. There is no fungicide that would be useful to combat the disease during the growing season, but you can make sure all crop debris is removed from the planting bed once the season's over, so it doesn't harbor spores over the winter. If a mulch layer is on the thin side or has areas of soil exposed where spores could splash up during rain or watering, see if you can apply a bit more mulch so the coverage is more thorough, though don't cover-up the base of the squash stem itself.

Miri

You're welcome, and good luck!