We finally bought our homestead out in the country. I wanted a main garden before I start tinkering with other areas of the land. I started with one basic 4 ft by 4 ft raised bed. I used some 2x6's that were left over from a decking project for framing the bed.
Before, I filled the bed with soil, I dug a hole 2 1/2 feet under the raised bed. This enabled me to put branches and other rotting wood in the hole. This is a permaculture method known as hugelkultur. The rotting wood absorbs moisture and decays over time. The plants root down to this rotting wood and have nutrients and moisture. This cuts down on the water needed. In fact, I water my garden only one to two times a week.
Next, I threw the grass I had cut out to dig the hole on top of the wood. As the grass decays it will provide more nitrogen, carbon and other nutrients to the plants. Then I piled back in the soil I took out.
Now, that I had my soil setup I put the 4x4 frame on top of the area. Inside the frame I added in compost, peat moss and some vermiculite. On top of this mix, I added some bark mulch to hold in moisture. The end result is a very prosperous garden with cucumber, tomatoes, beans, broccoli, and a green pepper plant that got shaded out. I am having to cut back the tomatoes every day so they don't crowd out the garden.