A couple weeks ago we ran a story about urban planners in Mexico City looking to build vertical gardens to help clean the air without taking up any space. But you don’t need to own a skyscraper to make a vertical garden of your own. In fact, making your own vertical garden (indoor or outdoor) is quite simple, and a green way to make use of limited space. If you’re looking to create an indoor vertical garden, all you really need is a good support for the plants or vines (a trellis or plant rack), direct sunlight, and a good watering system. If you want to make an outdoor vertical garden, the process is even simpler since nature does most of the work for you. Again, the easiest way is to grow vines on a trellis, or espalier some trees to the wall. If you’re looking for a nice selection of plants to try out on your own outdoor vertical garden, Savvy Gardening recommends climbing roses, honeysuckle, ivy, morning glories, or even something as simple as a hanging basket filled with carnations, petunias, dailies, or geraniums. Hopefully a vertical garden can help green up your walls this spring.