You've already read Before You Build Raised Beds and chosen to build beds with simple 2-inch thick boards. These are typically 2x6 inches but you can use whatever your lumber yard has available.
Prepare The Soil
If you can double dig the are where you will place your raised beds, that is best. This will ensure that the soil beneath the beds is loosened and free of rocks. If this is not possible, make sure your raised beds will be deep enough to accommodate the full roots of your plants. You might also consider putting hardware cloth in the bottoms of your beds if you're not planning on using any of the existing soil. This will discourage weeds and burrowing rodents like moles.
Lay Out the Beds
If you can have the long sides of each bed face south, that is ideal for equal light exposure for all plants growing in the bed. This way taller plants won't shade the smaller ones. But in some areas this matters less, and you should orient beds in a way that makes sense to you.
Often farmers will grow tomatoes or other tall, trellised plants in two-foot-wide beds to avoid the shading issue. These beds will be just one plant deep.
Leave Wide Pathways
You might want to leave the paths between your beds wide enough to wheel a wheelbarrow along them. This will make life a lot easier. If you plan to have grass grow in the pathways, make sure they are wide enough for a weedeater or small mower.
Another option is to mulch the pathways. Secure a double layer of landscape cloth to the ground, then cover with two to three inches of bark mulch, coarse sawdust, straw or whatever you like (just make sure that it's weed free!).
Gather Tools and Materials
First, gather your tools and materials:
- Lumber (2x6 boards, ideally cedar, but see here for other ideas)
- 2x4 or 4x4 lumber the depth of your bed (6 inches if using 2x6 boards) to use for corner posts and support posts if your bed will be longer than 8 feet.
- Fasteners: 3.5" #10 coated deck screws are good for this project.
- Cross supports: These provide stability for longer beds. 1/2" aluminum flat stock works well. You can cut it with a hacksaw and screw it in with 1" stainless screws.
- Tools: A hand saw, square, level, mallet, drill and hacksaw are the basic tools required for this project.
Build the Beds
It's easiest to build the beds in place, individually, so begin by clearing the location for the beds.
- Cut the frame for the beds to size. Screw the corners together temporarily with just two screws. Set a level on the frame and use blocks underneath on the ends and sides to make the bed level.
- Drive the corner posts into the ground a few inches and screw the corners of the boards into them from both sides, using two screws per side or more for deeper beds.
- Add additional boards for depth if you are using them. You can add these underneath the first row of boards. You may need to dig into the ground to get the boards to fit in places. Cut the top of the corner post flush with the top of the bed if needed.
- Check bed is level. Use your level all around the sides of the bed to make sure it is level, digging in and building up as needed.
- Fill in bed with soil. Smooth the pathways and begin to fill your bed with soil.
- Add cross bracing if needed. If your bed is longer than 8 feet or deeper than 18 inches, you may want to use 1/2" aluminum flat stock to help keep the sides of the bed from bowing outwards in the middle. Cut the stock with a hacksaw to the width of the bed. Attach to the posts at each side with screws.
- Finish filling the bed and plant! Add any soil amendments now, and mix the soil in the bed with a shovel or trowel. Use a fine spray to wet the soil evenly, then add more soil as needed (the wet soil will compact a bit).
For step-by-step instructions with photos: