Why You Should Build A
Raised Bed Garden
Why
build
a raised bed garden?
Today we have to deal with polluted and degraded
soils, cramped urban environments, and a host of other problems that
make growing directly out of the ground problematic in some areas.
Older civilizations dealt with some of these same issues, and came up
with a method of improving their growing abilities.
By 300 B.C., the Quechuas of South America had deployed raised bed
gardens to increase their yields while reducing soil erosion (1). Their
system of raised beds and irrigation, which they called Waru Warn, had
impressive results. It was successful enough that it's still being used
in Bolivia and Peru today.
Today, building a raised bed garden offers solutions to host of issues,
and they can be a valuable addition, and if nothing else, a fun
experiment, for the casual gardener or determined farmer.
What Is A Raised Bed Garden?
In its simplest form, a raised bed garden is
just hard material holding a large portion of rich good soil off the
ground for the purpose of vegetable, fruit, or ornamental plant
production. Sometimes these containers are open to the ground on the
bottom, but in the case of polluted soil, they're usually sealed off to
prevent contamination.
Container materials can include rocks dug out of the ground, old
bricks, cinder blocks, wood, and just about anything else you can
imagine. While I'd be leery of planting edibles in them, I've even seen
raised beds made out of old tires.
Construction is often as easy as stacking bricks or large rocks, but
the raised beds can also be complicated and involve mortar and other
materials.
You Can Build A
Raised Ben Garden Almost Anywhere
If you live in a city or even in some suburbs, finding good quality
land to grow on can be a problem. Most of the land that isn't used for
buildings is paved over with cement and asphalt in deference to the
almighty car.
Huge post-industrial brownfield sites that could have hosted large
farms are rendered useless because the soil is polluted with dangerous
chemicals. A raised bed garden can help solve these
problems.
Any sunny surface you can find, no matter where it
is, can be used for a raised bed garden. Unused parking spots, back
decks, contaminated land, and even sturdy roofs can host one without a
problem.
In these situations, you'll want to put a bottom in the bed to prevent
contact between the soil and the ground.
Even if you have unpolluted land to plant in, some soils just won't
cooperate.
Heavy clay or sandy soils can put a wrench in
garden plans.
While it's usually possible to rehabilitate these sites with a massive
sheet mulch application, some people just aren't interested in the
work. A raised bed can save them a lot of time and disappointment.
Kiss Your Water, Heat, and Soil Problems Goodbye
High up in Africa's tiny country of Lesotho, the
rain has two modes of arriving: in torrential downpours during the
summer and not at all during the winter.
The soils are infertile, rocky, and thin, and the weather shifts
between intense heat and fierce cold. Land cleared for planting usually
cracks during the droughts and then washes away under the onslaught of
winter rain. In short, agriculture is not easy.
While fruit
tree cultivation certainly has the possibility of drastically
improving the lives of people living there, when it comes to
vegetables, a raised bed garden can make a world of difference.
Luckily, one thing the country has in abundance is rocks, and people
there are putting them to good use.
Check out how
well
a raised bed garden can work in Lesotho.

Raised beds have great drainage to keep them in
good shape during deluges, and by covering them with straw or another
type of mulch, they can stand up to a good scorching.
They're filled with manure, compost, and dirt, and so the problem of
thin soils is bypassed. Because they're off the ground, they'll also
never be stepped on and compacted, which is a significant problem in
most gardens.
During the dry season they're kept wet with waste water from the
households, and a compost heap in the center recycles food scraps into
rich soil. As you can see, the vegetables that come out of them are
large and look delicious.
If they can accomplish this in Lesotho, you can do it just about
anywhere.
A Few Other Benefits
Because vegetables are usually grown quite close together in these
raised bed gardens, with their leaves just barely seperated, they shade
the soil more than in your average garden row.
This keeps the soil from drying out under the
hot sun and also shades out many weeds. Due to the compact nature of
the gardens, its easy to cover the soil with mulch, which will further
hinder weeds, conserve water and protect the soil. A final weed
deterrent deployable during construction is a barrier between the
raised bed and the soil. This combined with the clean compost being
used to fill the planter will ensure that weeds have a much harder time
taking root.
If you use stones, bricks or concrete as your building material,
they'll heat up during the day and emit that heat over the course of
the evening. This can keep the soil temperature several degrees higher
than you'll find in the regular ground soil, which can potentially
extend your growing season.
This concept can be built on by placing old windows over the raised bed
garden to create a greenhouse that will lengthen your growing season by
at least a month before and after your area's frost dates.
The elderly and disabled will also enjoy a raised bed garden because
they're several feet off the ground, which can make it easier for them
to get to. But even the healthiest person will probably prefer not
bending down so far to get to their salad.
A Circular Raised Bed Garden Works Better
The particular type of raised bed garden built in Lesotho is called a
keyhole garden. Besides the above listed benefits, they're more
efficient than the rows you typically find in western gardens.
In a traditional garden bed, we see single rows of plants interrupted
by walkways, which take up about half the garden space. With a raised
bed garden with paths going between every three or four rows, you cut
down the space wasted with walkways to about 30 percent.
By making a raised bed into a circle or a horseshoe,
even more space can be utilized.
When you wrap a typical 4 by 15-foot raised
bed into a circle with a small opening for a path, you get the wasted
space down from about 22 square feet - with an 18-inch-wide path down
one side of the raised bed- to 6 square feet. With a circular raised
bed, less than a quarter of the ground is surrendered to paths (2).
That quarter is usually in the form of the "keyhole," which refers to a
small walkway that resembled a keyhole when viewed from above.
Having curves also eliminats the monotonous monoculture farm look,
which I'm not a huge fan of. Even if you've got some straight lines,
including a circle can add a bit of charm to your garden.
That the charm happens to be more efficient is all the better.
Most pieces of land are square or rectangular, so placing a circular
raised bed garden along an edge can lead to waste if you don't plan
correctly.
One interesting option is to face the opening of the keyhole south so
it absorbs heat from the sun. This creates a perfect planting space for
a heat-loving plant or two, which will bask in the heat the keyhole
gives off.
This may cause problems for your walking path, but
it's a great way to create an ecological niche.
So Build One
If you want to make your own, check out these step
by step instructions for building a raised keyhole vegetable garden here.
Following Up:
As you can see, raised bed gardens, particularly
circular ones, have many benefits and are a great tool for any organic
gardener.
The high-quality compost and amendments you can
concentrate into them produces tasty crops and larger yields than
you're likely to get growing in soil that hasn't been heavily improved.
Give one a try and you probably won't regret it.
Watch Andrew's video overview of his keyhole garden here.
Learn about a healthy raw food diet
that will be improved by organic produce grown in a raised bed garden.
For more gardening articles, click here.
Raised Bed Garden
Sources:
1) "Raised
beds and waru waru cultivation." Organization of American States,
Department of Sustainable Development.
2) Hemenway, Toby.
"Gaia's Garden." pg 47.
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