I like to have dried broccoli on hand to throw in rice and pasta dishes. The last batch I made was purchased frozen, and therefore only had to be cut into 1" floret pieces. Broccoli only take about 6-8 hours in a 135 degree dehydrator to dry completely, making it one of the fastest drying vegetables.
If you wish to dry fresh broccoli, it must be blanched after chopping into 1" floret pieces. You can dehydrate the stems, but they tend to be woody after re-hydration and isn't recommended. To blanch, simply bring a pot of water to a boil and submerge chopped florets for 2 minutes. After 2 minutes, quickly strain the broccoli and plunge it into ice water to stop the cooking process. Drain it well on paper towels and place them in the dehydrator in a single layer on 135 degrees for 6-8 hours as you would frozen broccoli.
When they are completely dry, they will be crispy and the individual floret tops will easily crumble from the stem. As with other vegetables we've dehydrated, store your dried broccoli in a glass jar in a cool, dry, dark place. Sealing with a Food Saver, or placing an oxygen absorber in the jar will extend shelf life. It will be good for at least one year without sealing if stored properly.