Ask Mr. Smarty Plants

There are specific definitions for full sun, part sun, part shade and full shade, but with these definitions there is a healthy dose of art that's thrown in with the science of it.  We define full sun as an area that receives more than six hours of direct sunlight each day.  Part sun is defined as receiving four to six hours of sun each day, while part shade areas get two to four hours of sun daily and full shade areas are defined as receiving fewer than two hours of direct sunlight each day.  However, the mitigating circumstances can be a bit tricky.  For example, afternoon sun tends to be more intense than morning sun.  Sometimes, reflected sunlight can play a significant role in light quality and intensity.  Finally, geography also affects light intensity with desert areas and high-elevation regions having generally more intense sunlight than other places.