Stopping powdery mildew

You can buy a gallon of skim milk(non fat) and just spray it from the
bottle. No dilution necessary.
Or, you can buy non fat dry milk and mix it as follows
one part dry non fat milk
nine parts water.
A good schedule is every two weeks or oftener if you see a problem sooner
than the two week period.

It is really important to spray in the cool of the day, I do it in the
evening after leaves have cooled down.
It is really important to keep all bad looking leaves trimmed off of plants
so that spores don't continue to infect healthy leaves.

It is very hot in Florida. I used to live there. Have you thought of using
some 50 per cent shade cloth to cool down your plants when temps rise into
the 90's?

Always water at ground level, do not wet the leaves. Always water in the
morning in case the leaves do get wet, they have a chance to dry before night
fall.

Hot days and cool, moist nights are a perfect media for powdery mildew.
That is exactly what we are dealing with here in Long Beach, California. Our
plants are simply dripping with dew each and every morning.