Have you ever heard of a garden that waters and fertilizes itself? Originating from the continent of Africa we will take a peek down the hole and see what’s what in a “keyhole garden.” The sustainable gardening method was developed by a humanitarian aid organization in Africa, where resources are scarce and the climate unforgiving. There, three keyhole gardens can reportedly feed a family of 10 all year long.
A keyhole garden is the ultimate raised-bed planter. It is often built in the shape of a circle measuring about 2.5 m. in diameter that stands waist-high and is notched like a pie with a slice cut away. A hole in the center holds a composting basket that moistens and nourishes the soil. The garden, which from above looks like a keyhole, can be built with recycled materials and requires less water than a conventional garden.
The concept is incredibly simple, and the keyhole raised bed is quite easy to construct with hardly any tools and only very inexpensive materials. Keyhole gardens are now being used in different settings all over the world. They reportedly can be made with bricks, stone, rocks – just about anything that will hold soil in place.
Organic material from the garden (lawn clippings, leaves, etc.) and kitchen scraps that one would ordinarily compost are tossed directly into the central core to eventually feed the surrounding soil. While the keyhole provides easy access to the composting basket in the center, almost any raised bed with a fairly large in diameter will work.
“You can adapt the concept to whatever you have available,”
Some builders enrich the soil directly adding recycled newspapers, telephone books and cardboard, which are reportedly adding carbon, nitrogen and air to the soil.
A keyhole garden offers as its main advantages the constant availability and efficient use of nutrients and water while also being ergonomic in the ability to tend your beds from the one position. You literally work from within the bed and rotate to access every inch of it. Plus, the bed is raised so you don’t need to get on your knees when conducting your gardening tasks.
Why would I bother building one of these?
The ultimate answer, apart from the features mentioned earlier, is the efficient use of space. Consider creating a square, raised garden bed that you could access from every angle. It could only be 1m x 1m but would take up a space measuring 2m x 2m for access. Therefore, this one garden bed would require 4sq. mtrs but only provide 1sq. m of gardening plot. The arable portion of this plot is only 25%.
A keyhole garden, on the other hand – with the measurements quoted earlier, would take up an area totaling 9 sq.m and provide a plot size of 5.78 sq.m. The arable portion of this plot is a whopping 64%.
Even if you were to try and maximise the space used for the square garden beds the best percentage of arable land that you would get would still only be 36%, almost half that of the keyhole garden. So, it makes complete sense to build these rather than waste valuable space constructing their square counterparts.
And you don’t have to get all medieval in your garden with sticks, rocks and stones, check out this high tech version below.