Creating Raised Bed Gardens

I originally wrote this article for use in our online newsletter and in a local gardening magazine:

With spring quickly approaching, many people are starting to plan for their vegetable and herb gardens.  If you are tired of the traditional gardening style of individual rows and tons of weeding, consider creating a raised bed garden.  Raised beds allow for anyone to easily overcome the problems created by poor soil quality, and they can easily be scaled to fit any need.

Raised beds are simply any type of bed built on top of the native soil.  They can use native soil, but usually they are a combination of native soils and soil amendments.  Raised beds are usually contained by wood or stone enclosures, but they can also simply consist of mounded earth.  Raised bed gardens offer many advantages:

·     Raised beds warm up faster in the spring allowing you to work the soil and plant earlier.

·     Raised beds drain better.

·     Raised beds do not become compacted because they are accessible from all sides.

·     It is fairly easy to control the soil conditions of raised beds.

·     Raised beds are easier to maintain.

You can choose from a variety of materials to construct your raised bed, but for the sake of demonstration, I’m going to explain the process that I use for constructing wooden raised beds.  The first step of the process is collecting the materials.  For this project you will need three 8 foot cedar 2” x 12” boards, galvanized screws or nails, newspaper, straw, blood meal, compost, leaves (optional), and potting mix.

After you have collected the materials select a site for your bed that receives at least 8 hours of sun per day, and then assemble the bed.  The great thing about using eight foot boards is that you an easily create a 4 ft. x 8 ft. bed by cutting one of the three boards in half.  (Note: Never use treated boards to build beds or compost bins that will be used for growing food.  The chemicals used to treat the boards are toxic and can be absorbed by the plants and you.)  After making your cut, nail or screw the bed together using the 8 foot boards for the sides and the 4 foot pieces for the ends.  Finally, make sure the bed is level as an uneven surface will not drain properly.

Once your bed is assembled you can now start adding ingredients to make the perfect planting mix.  If you are building your raised bed on grass, add a layer of newspaper to the bottom to smother the grass.  The paper will later decompose and contribute nutrients to the soil. 

Above the paper add about 4 inches of straw, but make sure that the straw has been winnowed to prevent weeds later on.  Next, add about three cups of blood meal to the straw.  This will aid decomposition and add nitrogen to the mixture.  If you are unsure if your straw has been winnowed, add another layer of newspaper to smother any potential weeds. 

On top of the straw add a layer of leaves and about a cup of blood meal.  Leaves make an excellent soil amendment if you have them available.  On top of the leaves add some compost.  This will not only add important nutrients to the mixture, but it will also impart important microbes to begin the decomposition of the lower layers.

Finally, add about a five inch layer of potting mix to finish the bed.  This takes about five bags.  Now you might be thinking that the bed is finished and ready to plant, but it isn’t.  It is best to let the bed set for at least a few weeks to allow for decomposition; however, allowing it to set over the winter is best.

Your newly constructed bed should last for about 8-10 years if it is constructed from cedar.  Each fall you should remove some of the old soil and replace it with compost.  This will allow for the nutrients to be replaced that were lost during the growing season.  You can also build a short frame above your raised bed and cover it will plastic film to form a low cost winter garden.  When it comes to raised beds, whether expensive or inexpensive, you are only limited by your imagination when it comes to design and uses.