The advantages of raised beds, whether you are growing herbs, flowers or vegetables are numerous. Hopefully, you have decided to move forward with a raised bed project and are ready to begin. Remember, boxes can be constructed out of a variety of materials, including brick, cinder blocks, rock, etc, but by far the most common is wood, so let’s focus on that.
First, you must decide on the type of wood you are going to use. Both cedar and redwood are rot resistant and quite attractive, but they are also expensive. For my garden beds, I selected pressure treated lumber manufactured with alkaline copper quat (ACQ) which has been approved by the Environmental Protection Agency for use when growing food crops. I have over 50 raised beds, so the cost savings in using ACQ versus redwood was quite significant.
Herbs & Vegetables
If you are going to grow a variety of herbs and vegetables, you will want to purchase lumber that is a minimum of 12 inches deep so that when you rotate your crops from season to season you will always have adequate depth to support everything from parsley to potatoes. Plan on boxes that are no wider than four feet, but they can be as long as you would like. Next, put some thought into the location of your beds. Think sun, sun, sun, and a convenient level location with access to water. Also, remember to leave enough space between the beds to maneuver equipment like mowers and garden carts, usually three or four feet.
Having selected your site a little prep work will pay nice dividends in the long run. Dig out the turf and any established weeds and cover the area with some ground cloth to smother the weeds. You can also lay in a sheet of wire mesh to prevent moles and chipmunks from tunneling into the beds from below.
Constructing the beds is pretty simple.
All you really need are stainless steel L brackets and screws, a portable drill and a power screwdriver. For each corner of a 12 inch deep box you should use two 4 inch brackets requiring 16 screws. Take one of the four foot end pieces and align it to the outside of a sidewall piece and screw in two L brackets. Repeat this on each corner and you are good to go. Many of my boxes are over 25 years old and have held up really well using this method. One labor saving tip is to deliver the cut pieces of lumber to your site before construction so you don’t have to move the finished box from one place to another.
It is time to fill your bed with high quality composted soil. Don’t simply dig up soil from around your property or from an old garden. This is the only time you be able start with clean weed free soil. Previously compost filled soil is ideal for gardens and can be delivered by most landscaping companies. Give these companies the total square footage of your beds and they can tell you how much to order. Upon delivery I like to mix in some peat moss and bit of sand to equal about 10% of the total soil volume. This “light” soil will promote good drainage and a healthy environment for young roots to expand and prosper.