Peel the cucumber. Chop into bite-size pieces.
Remove core from apple and pear. Chop both into bite-size pieces.
Peel ginger.
Chop celery into bite-size pieces.
Coarsely chop the kale, lettuce, and spinach.
Squeeze the juice from the lemon, removing seeds as needed.
Place all the solid ingredients into the blender bowl, starting with the hardest ingredients on the bottom. Do not press down on the ingredients in the bowl. Roll the leaves into tight wads before placing them in the bowl.
Add the lemon juice to the blender bowl.
Add four cups of water to the blender bowl.
Blend on low for 20 seconds, then on high for 30 seconds (or use the Smoothie program on your blender if it has such an option).
Drink immediately or store in an airtight container in the refrigerator.