Here is a goal: A concrete porch/ patio can be cleaned how?

How would you accomplish this goal?
Mix 1/2 cup baking soda to one gallon of water for a gentle cleaning solution. Add 1/8 cup of liquid dish detergent. Spray on patio surface, let sit for 30 minutes, then scrub and rinse. For heavily stained or mildewed patios, you may need a pressure washer.