Good quality broccoli should have fresh-looking, light green stalks of consistent thickness. Bud clusters should be compact and dark green with some purple tinge. When pulled apart, some bud clusters may appear yellow around the edges. This does not affect product quality; it simply means that the clusters were not exposed to sunlight during growing.
Avoid broccoli with open, flowering, discolored, or water-soaked bud clusters and tough, woody stems.