Be sure to prep your garden space first by adding the proper fertilizer.  Perform a soil test if necessary.  Then, plant accordingly.  Ensure your garden area is landscaped and appealing so when potential buyers come to view your home, they can imagine what they might plant in the space.  A properly landscaped garden can give you and extra edge when showing your home to a potential buyer.  Always inspect the area before taking a potential buyer to ensure it is safe and appealing.