Raised bed gardens put you, the gardener, in control! If the soil in your yard is unworkable, despite the fertilizers and amendments you add, consider using the growing medium of your choice in a raised bed.
A raised bed is basically a large, permanent container garden. Since you fill the box with soil, you don’t have to mess with the infertile native soil below. Raised bed gardens have many benefits over traditional flat-bed gardens, including weed control and improved drainage.
Since raised bed gardens are walled in, you’ll want to keep yours on the smaller side so you can reach the center of the garden from all sides. A 5-foot square is about as big as you should attempt, but there’s nothing (but available space) to stop you from having more than one raised bed. Square raised beds are ideal for an intensive gardening practice known as square-foot gardening.
A raised bed should be at least 12-inches tall to allow vegetables to develop strong, deep roots. I built my raised garden from 16-inch wide pine boards to create a rectangular garden 5-feet long by 3-feet wide, but the size and shape of yours will be largely determined by the available space in your yard. Building a raised bed is a simple carpentry project, especially if you get the hardware store to cut the boards to size for you. These instructions from Sunset magazine may prove useful for inspiration and construction tips.
As far as filling the raised bed garden, I used a combination of compost, steer manure and garden soil. Compost drains well and holds moisture, so make it an addition to whichever soil mix you choose. If your garden is 12-inches high, use the square footage of the garden to determine how many cubic feet of soil you’ll need. Fill the bed to within 1 inch of the top and get planting!