If you are planting Saffron Crocus bulbs to harvest the stamens to cook with, you will want to do this once they begin blooming.
Harvesting Saffron: When the flowers are fresh, simply remove the bright red stigmas you'll see in each flower's center; they carry the saffron spice. You can use it immediately in the fresh form, or dry it for later use. To dry your saffron, simply spread the red stigmas out for several days on a paper towel in a warm dry place. Once they're dry, store them in an air-tight container in a cool, dark place, and use the saffron whenever you like.
For more information on growing and harvesting Saffron Crocus, read our blog post: Saffron Crocus: Delightful and Delicious.