If you're looking for something space efficient but can produce high yields, raised bed gardening would be the best option for you to try. Besides being efficient when it comes to space, it also solves a number of other issues such as dealing with difficult soil as well as your garden's accessibility. Raised bed gardens are basically made up of mounded soil that's surrounded by a frame to make sure it doesn't fall apart. They are usually at least 3 to 4 inches above the ground itself and each "bed" is typically separated by a pathway. Plants would cover the entire surface of these beds and the paths would provide the gardener with ample space to work in, making sure that they don't end up stepping on the soil in the process. A raised bed can be 3 to 5 feet across and the length can vary depending on the need. You'll be able to grow a wide variety of crops vegetables on it as well as herbs. Perennial and annual flowers also thrive in this type of gardening along with roses, shrubs and even berry bushes.