Recycled plastic bottle vegetable gardening is an effective way to combat hunger, desertification, and grow plants in urban areas. By collecting plastic bottles from around the world and teaching people how to use them for container gardening, they can help reduce hunger, educate children, decrease plastic waste, and provide a sustainable food source even in dry or urban environments. The document shows examples of using cut plastic bottles for container gardening, with the top portion placed over the bottom to create planters that can grow vegetables like parsley, lettuce, and cauliflower.