Raised bed gardening is an excellent garden plan for people with poor soil, people who have trouble bending to reach gardens on the ground or people who want to get an increased yield in their current garden. Built above the existing soil, a raised bed garden can give you twice as much produce as you previously harvested with traditional planting methods.
Raised bed gardens are larger versions of container gardens. Built above the existing soil, they can be placed directly on the ground or built up on platforms or legs, to reach whatever is your desired height. After the container is built, the garden is filled with soil and intensively planted.
Your garden plan depends on what plants you want to grow. Decide how many plants you need of each variety and plan the size accordingly. Raised beds are planted in an intensive square pattern, so more can be grown in a smaller area, but don't underestimate the size of your planters. It is much less easy to add on to a raised bed garden than a traditional one, so be generous in your plans.
Build the frame for your garden. Many materials can be used, such as planks or railroad ties. Gardens can be built on stands or legs to raise them to waist level for those with trouble bending. After you build your frame, fill it with soil and compost to a depth of at least 12 inches. Make sure that the entire design is level, so that water will not pool at one end.
Read the seed packets for your chosen plants. Notice that most planting instructions call for plants to be spaced a certain number of inches apart, while rows are to be about a foot apart or more. This is only for cultivation in traditional gardens, not for the plant's benefit. Use the smaller number for plant separation, and plant each seed or seedling this far apart in all directions. For example, if your carrots are to be 3 inches apart, you can plant 16 of them in 1 square foot of garden space.
Intensive gardens need a bit more care than traditional gardens, as they will dry out faster and need more nutrients. Water daily if need be, and feed monthly. There are more plants per square foot, so the nutrient needs are proportionally larger.
Raised bed gardens begin with the best soil that you can obtain, so there is no problem with adjusting soil. These gardens will grow the largest crop possible. They drain better, so they are healthier for plants. There is no chance of compacting the soil, as these gardens are not walked on, so there roots have the maximum amount of room to grow. They can be planted much more compactly, so the yield is much larger than in any traditional garden.
If you truly have a space problem, raised bed gardens are still a good possibility. They may be your only possibility for growing vegetables in some circumstances. Rooftop gardens are raised bed gardens built totally above ground. With much smaller areas available, planter boxes and large flower pots can use the same methods for growing fruits and vegetables. Even window herb gardens are a form of raised bed gardening, taken to the smallest extreme.