I harvested a lot of squash flowers from my garden already. Everyday as I wake up, my destination is my vegetable garden at the backyard. I have to be careful though because there are lots of bees eating the pollen of the flowers. I have to shoo them away before I will cut the flowers with my scissors. After harvesting the flowers, I put them in a plastic bag and put it inside the refrigerator so it will last longer.
Cleaning & preparing squash flowers
An hour or two just before cooking, place the flowers in a colander and rinse them well inside and out with cold water. Gently tug the petals open and fill with water. Stick you finger inside the flower to dig out any insects that may be trapped inside. If the flowers are not dry by the time you're ready to cook with them, just pat them lightly dry with a paper towel.
While some squash flower connoisseurs advocate removing the innards of both male and female flowers, others prefer leaving them in with no ill effects. Personally, I leave the flower as intact as possible to get the most vitamins and nutrients from this rare treat -- I suspect this may also contribute to added merriment around the table after consumption.