Raised bed gardening is more than just a trend. It has some real advantages in terms of space, ergonomics, and logistics. It is easier to install deer protection around a raised bed than a big garden plot. If you are challenged by a shady yard, a raised bed may be just the thing to tuck into a sunny corner.
Let’s explore some of the advantages in more depth, and then some examples where you might NOT want to use a raised bed. Finally, we’ll take a tour of types of raised bed materials and how to choose which ones best suit your gardening goals.
Advantages of Raised Beds
If the thought of a big garden seems overwhelming, raised beds can be a great way to get started. If squatting and kneeling are not for you, raised beds can be made to ergonomic friendly specifications at almost any height and depth. Here are seven advantages of raised beds:
Can be built to meet accessibility needs
Easier to fence to keep out pests
Defines planting area
The soil warms faster
Prevents rhizome rooted weeds such as Creeping Charlie and horsetails
Facilitates minimizing soil disturbance
Easier to address soil structure and drainage
These last two points are important factors in building soil health.
Limitations of Raised Beds
But there are limitations or trade-offs in raised bed gardens. The most obvious one is scale. If the goal is to grow a lot of produce, you will need a lot of raised beds. They require the use of hand tools over labor-saving or production-scale methods.
Scale
Requires more frequent watering
Space
Depends on type of material (e.g. wood will deteriorate–but that may be a benefit?)
Cost
And please note: some things might NOT grow as well in a raised bed–things that need to spread or take a lot of space, things that will be tall, or things that need awhile to become established. Below are some examples:
Asparagus or strawberries
Broccoli or cauliflower–things that want to spread out or take up a lot of space.
Large squash and melons that spread horizontally
Potatoes grow fine in a raised bed but are hard to dig out at harvest time
Corn
Also note: some varieties/cultivars may be better suited to raised beds–such as dwarf varieties.
Tour of Materials
Fabric - fabric is lightweight. It is easy to water and good drainage is almost guaranteed. Depending on what is being grown, it may mean more frequent watering. Landscape fabrics vary in their ratings, but fabric with a 20-year rating will likely last as long as one made of wood.
Wood - often readily available and affordable, wood also has the versatility to be made into almost any size or shape. One caution: while it may be tempting to reuse wood from another project, consider if eco-certified wood might be a better choice to avoid chemicals used in wood processing.
Concrete or brick - in this case, the reuse hazards are less. And it can be season-extending in spring or fall to use a material that will hold heat longer, like concrete will. This heat-holding may be a liability in the hottest part of summer, however.
Metal - metal for raised beds runs the gamut from very expense structures built specifically for gardening to re-using wash tubs or water troughs. Consider carefully whether it’s appropriate for growing food: https://depts.washington.edu/hortlib/pal/growing-edible-plants-in-galvanized-containers/
Hand-dug raised beds - the soil itself can be used in a pile to make a raised bed.
Hugelkultur - a type of no-dig raised bed that uses natural materials such as logs, branches, leaves, grass clipping for structural support. As these materials break down, they also contribute to soil health. This requires some more forethought, and has a very different aesthetic than other raised beds, but depending on your growing goals, it may have advantages and is certainly sustainable in the long run.
How to Choose Bed Material
With all those material choices, how do you choose? First and foremost, think about what you plan to grow and when (like the concrete/brick options extend seasons). What is readily available at your site? Aesthetics may play a role too–what adds to your vision of a garden? What is your skill level/commitment to DIY? There are great video tutorials and instructions on how to build wooden beds, for example. Here is one for wooden raised beds and another one for raised beds with legs.
Do you have the time and skills and/or interest to build? Budget plays a role here too–how much do you wish to invest? Finally–what amount of maintenance are you willing to commit to?
For example, hand-dug raised beds (beds without framing) are typically redug every few years, and the walkways are heavily mulched. They are good for larger areas or production systems. Also, because there is no infrastructure, they can easily be taken out of production and "rested" as part of a rotation. At scale, these can be made with a bed shaper - https://kerrcenter.com/video/using-bed-shaper/ (Bed shapers can also be used to hill potatoes.)
There are many factors to consider when choosing raised bed gardening. It may be helpful to see some real life examples. Check out community gardens in your area which may have raised beds. This recent blog post explored community gardens in both Northern Lakes and the Driftless regions.