Answer: I don't think you need plans or blueprints to build a raised bed. Raised planting beds should be set up in north/south orientation to allow the maximum direct sunlight to both sides. Avoid using creosote or pentachlorophenol treated lumber (such as railroad ties) for the frames, to prevent these chemicals from leaching into the soil and injuring your plants. Use pressure-treated lumber, redwood poles, logs, concrete block or brick.
Start by marking out the perimeter of the bed using stakes and string (or a hose) as a guide. Dig a shallow (2 inch) trench inside this guideline so that as you lay out the first level of your chosen building material, it is recessed slightly into the ground. If the ground is uneven, dig the high end deeper into the ground, so that the end result is more or less level. This will make further construction much easier.
Depending on your situation, design, and needs, you may opt to add all or part of the topsoil to the raised bed at this time. It is sometimes easier to have most of the soil in place to act as a back support as you build the retaining wall.
In other cases it is more prudent, and easier to add the soil as you build the wall.
(Don't forget to mix the bottom layers of the added topsoil in with the native soil... Remember that any additional compost, manure, leaf mold, or other organic material which you add to this planting mix will provide the soil with essential nutrients for plant growth, and at the same time, greatly improve drainage. Now is by far the easiest time to do this!)
Each subsequent course should be set slightly farther inward. If you are using logs or timbers, align them so that the seams are staggered, and nail them into place with 6 inch or longer galvanized spikes. (Pre-drilling the nail holes will prevent the wood from splitting.) At the corners, the exposed ends should be alternated (log cabin style) for strength and stability.
Concrete blocks and bricks should also be set so that the seams don't line up. For strength, steel bars should be driven into the soil through the existing holes in the blocks. The holes can then be filled with cement, soil, or gravel.
Building the retaining wall with stones requires the same abilities as to do jigsaw puzzles. The base of the wall should be considerably wider than the top (pyramid style). Interlock the stones together as closely as possible, using small rocks and gravel to fill the voids.
Fill the bed with quality topsoil, allow it to settle for a week or so, and add more soil as needed. Because the soil will continue to settle, you may have to add more soil the following year.
Dig a small trench around the entire perimeter of the planting bed, and fill it with gravel to divert excess water away from the pathway around the bed, during rainy weather.
Happy Gardening! Your raised bed is now ready for planting.
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