Solar access

This could be a shading study that examines how much the sun shining on the garden area is blocked by nearby buildings, trees, or other obstructions. You could use a 3-D modeling program like SketchUp or Revit that models sun and shadows for a particular location at different times of the year, diagrams showing the height of nearby obstructions and the angle of the sun during the growing season, or a rarely used but handy tool called the "Solar Pathfinder." 

The credit language says "as applicable," so if you have a site with very few obstructions, a simple site section showing the position of the sun might be sufficient. (In the northern hemisphere, on June 21st, the angle of the sun at noon is roughly 90 degrees minus the project latitude, plus 23.5 degrees. December 21st: 90 - latitude - 23.5 deg. On March 21 & Sept 21 the noon sun  angle = 90 - latitude.)