RAISED BED GARDENING WITH PLANTERS
In many everyday landscape situations
the home gardener is faced with the problem of trying to cultivate
plants in extremely poor soil conditions. New housing plans are notorious for
a general lack of topsoil and/or compacted soil which creates
extremely poor growing conditions
Who is affected?
Quite often this is a new homeowner who is trying to work with soil
that's been severely disturbed and/or compacted. It's entirely possible
that most of the lot's native topsoil was removed when the housing
development was graded. Usually, only an inch or two of
topsoil is spread over a new lawn following home construction. Therefore,
homeowners are faced with trying to plant in heavy clay subsoil which
lacks drainage and tilth.
What's the solution?
Without getting into an extensive (and expensive) soil modification
program, the quick solution is installing raised beds. This allows
for new topsoil, organic amendments and fertilizer to be custom
mixed to suit the plants being grown.
A second advantage is that by its very nature, a raised bed drains
much better than soil at the same grade of the surrounding lawn and
What type of raised bed?
The most basic type of raised bed is as simple as a pile of
topsoil. This is usually referred to as 'mounding' and can be made
more pleasing to the eye with proper shaping and contouring. But in
the truest sense of the term, it refers to a bed that's constructed
above ground using walls that create an actual planter. Usually, 12
to 18 inches of height is enough to provide a good root zone for most
annuals, vegetables and smaller ornamentals.
What about curved walls?
If curved edges are desired, it's necessary to use one of the precast wall stone products which are
so readily available today. These
products come in an assortment of colors and sizes. Proper
construction practices must be followed (proper footer, etc) to
increase the integrity and longevity of the wall. The taller the
finished wall, the more important proper construction becomes.
Which type is the easiest to build?
The simplest form of raised bed planter to construct is created with
6x6 inch (or 6x8 inch) timbers, provided it's acceptable to have
straight edges on the planter. It's especially important to use decay-resistant
timbers for any project where there will be soil contact. If you use
treated timbers, especially for a vegetable bed, it's extremely important
to use ones that are safe for this purpose.
ADVANTAGES & DISADVANTAGES
- Better soil conditions for
digging and growing
- Opportunity to add amendments
from the get go
- Provides a raised wall to sit on
- Timbers may need to be replaced
- Wall construction costs
- More frequent watering required
- Pressure treated timbers
Available in 6x6 inch or 6x8 inch
dimensions. Standard length is usually 8 feet long. Sometimes
available in 2-foot increments beyond the 8 foot length (10, 12,
14... foot) Timber construction requires a heavy duty
drill and extended drill bit, chain saw or large cutoff saw,
12-inch spikes, sledge hammer, etc.
Note: If using treated timbers for a vegetable garden planter
make sure the chemical used to treat the timbers is safe for
This raised bed was quickly
constructed using eight 6x6 timbers (8-feet long) and filling it with
50% topsoil and 50% mushroom manure. Notice how the corner timbers
overlap each other for added strength.
- Precast wall stones
Precast products come in a wide variety of shapes, sizes and
colors. While smaller stones might work well for smaller
projects, heavier stones will be necessary for larger and deeper
Proper construction techniques are very important, so follow the
manufacturers specifications for best results.
Note: Due to the weight of most of these products, consider
contracting the job. If doing the project yourself, you may need
to have these delivered by heavy truck. Plan ahead.
- Natural stone
Some tradesmen and individuals have a knack for constructing
natural stone walls, but most people don't. Precast products are
easier for most amateurs to use due to their uniform sizing.
- Soil mix
Prepare a good soil mix for your raised bed using good topsoil,
organic matter, lime if needed and the appropriate amount and
type of fertilizer. Mix all the various elements together before
placing the mix in the raised bed. Lightly compact the mix to
take out excessive air space.
Note: Most mixes will settle during the first year, so
anticipate adding more mix for the second season.
composting for the garden
vegetable garden mulches