How To Build A Raised Garden Bed

Walter Green - General Manager
September 3, 2015

How To Build A Raised Garden Bed

For the soil and drainage poor gardener, a raised garden bed offers the opportunity to perfect your environment and control many of the factors that are otherwise left up to nature. Building a raised garden bed allows you to optimize soil nutrients and drainage, even as you prevent soil erosion and save your back from added strain during weeding and harvesting.

The first step to building a raised bed is choosing a location that fits the needs of whatever you choose to grow—ideally you want a spot that receives full sun for about six to eight hours out of the day. It's also important to remember that just because a bed can correct poor drainage, that doesn't mean you should set it in a marshy area.

The second thing you'll want to consider is your choice of the material used to build the raised bed. Many materials can be used to form the framing, some of which are more cost effective than others. On the inexpensive side, concrete blocks work well, as does pressure-treated lumber. On the more expensive side of things, decorative stone or brick also work well.

Should you decide to use lumber, you're going to want to build the frame with posts that are set in the ground and can offer stability, or you could dig a trench that's at least a few inches deep. Lay out the plot no more than three or four feet wide. It's important to keep in mind that you need to be able to reach all the plants to harvest and water. Your raised garden bed should be at least a foot deep, although for plants with deep roots, you'll need to go as deep as 18 inches. (When using any kind of treated wood to build a bed for any kind of edible plants or vegetables, be sure to line the lumber in order to prevent it from leaching toxins into the soil.)

For the more ambitious gardener, installing an irrigation system can make your raised bed even lower maintenance, micro-sprinklers or hose systems often work the best and don’t wet the foliage (which can cause mold). Since an irrigation system is optional, you can either put one in place before adding soil to the bed, or simply count on hand-watering through the dry season.

The next thing you will need to do is fill the bed with a sandy clay loam soil that’s been well-mixed with compost or other organic matter. After planting, you can add mulch (try pine straw or mini pine bark nuggets) as the finishing touch, an especially important one to raised beds, which can be prone to drying out.

For a raised garden bed that’s ornamental—to be planted with flowers and other beautiful plants—aesthetics are of course the most important consideration in plant selection and layout. Trellises and stakes will help conserve space, as plants climb instead of sprawl. Once you’re ready to plant, add seedlings of various varieties and next year, you’ll have a bonus: The soil in raised garden beds heats up faster than the rest of the landscape, so you get on average a two-week head start in planting.

Now the only thing that's left to do is stand back and admire your work. And of course enjoy the flowers, plants, and vegetables that are now inhabiting your new raised garden bed!