Friday, April 29, 2011

Adding Raised Beds to Your Garden By Joyce D’Agostino

Those of us who live in the front range of Colorado know that our compacted clay soils are a true challenge to having a successful garden.  In addition to the hard clay, the high pH of our soil
s here and throughout the state due to the free lime that naturally exists also can pose a problem. 

One answer is to add raised beds to your garden. Raised beds allow you to grow your garden vegetables and flowers in quality soil and nutrients that will allow you to get higher yields and better results from your gardening efforts.

If you purchase a raised bed kit, you may notice that many of them are only about 6” deep and most suggest you buy more than one kit for the optimum depth. Outside of some small annuals, most plants want and need a deeper root medium, so you will need at least one more kit, or add purchased railroad ties or similar timbers to give you the right height and depth.

Most garden vegetables such as tomatoes and squash require full sun for most of the day. Check your seed packets or the information included with the plants you purchase to know how much sun is required. For example, if you choose plants that require full sun or sun for most of the day be sure that the placement of your bed will not have partial or heavy shade.

After choosing the location, we raked up all of the bark that was in the area and set it aside. Wood bark should not be incorporated into your soil because it takes a long time to decay  and also ties up the nitrogen necessary for good plant growth. When your beds are completed, you can use the bark to make pathways in between the beds but be sure to not add the bark to the new soil.

The next step is to prepare your soil. The soil in the areas of our planned beds was covered not only with landscape fabric but bark mulch on top. Landscape fabric is often used by gardeners and landscapers to help control weeds, but over time the pores of the fabric become clogged from dust, debris and soil and torn. The result is that the fabric no longer allows the proper amount of air and water and this can stop the beneficial bacteria and organisms in your soil to be present and weeds can penetrate through the tears. It was necessary to remove this worn out fabric and discard it.

Since the soil under this fabric was very compact, we used a pitchfork to loosen and aerate the soil in the area where the beds will be placed.We added some new soil to this area along with a layer of leaves that we saved from the fall. As the plants grow, it was necessary to loosen the soil under these beds so that their roots will not stop at the compacted soil which could act as a hard barrier

The new soil was then added to the beds. Choosing a quality soil is crucial. Take time to read the contents on the bag of soil. If it states vague ingredients such as “organic matter” then you may want to be cautious. If you are in doubt, buy a small bag of the soil that you are considering, open it and and carefully examine the contents. Watch for topsoil that contains a large amount of things like wood bark and chips, rocks and other matter that was used as a filler. A good topsoil will be clean of debris. Many topsoils and composts are not regulated as to their content so can vary widely from high quality to soil that was scraped from construction sites which could contain harmful chemicals, nails, glass and other debris.

There are several good articles that can help you plan your new raised beds and choose the right materials.  Go to and click on publications. There are many free fact sheets that can help you with all of your gardening needs. The following fact sheets discuss raised beds and choosing your soil:; and