How big do asparagus grow?

Asparagus spears typically grow to be between 6 to 12 inches tall when harvested. However, they can reach heights of up to 20 inches if left unharvested and allowed to mature. The thickness of the spears can vary, with some being as thin as a pencil and others as thick as a finger, depending on growing conditions and age. Proper care and cultivation can lead to healthy, robust growth.