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Styles Click to view images of keyhole gardens | The basic idea is to to create an efficient, manageable, constant natural plant food in a space that allows the gardener to reach all the vegetables grown. The center is wire basket approximately 1 ft in diameter. You put all uncooked unused plant refuse into the basket to compost. You can also water the plants and assist the composting of the plant refuse by using grey water from washing dishes and other grey water sources. | ||
Construction | As seen from the Keyhole garden images, you can build one from almost any material. The slot or keyhole is to allow access for placing vegetable refuse into the wire basket to allow the refuse to compost, leeching into the surrounding growing area to feed the plants. Generally the diameter should be around six ft with the wire basket centered in the circle as close as possible. The sides should be approximately 30-36 inches high. | ||
Fill | The fill should be built up in layers starting with the coarsest materials on the bottom layer, (rocks from 3-4in down to gravel, sloping down from the center basket), 2nd layer (sticks, small logs, cardboard, maintaining the slope down and out to the perimeter), 3rd layer (bark mulch and course growing medium, maintaining the slope), final layer (fine growing medium, soil, peat, other smaller particle growing medium). | ||
The Keyhole Garden image | The image to the right is a kit ordered from The Keyhole Farm. We have had the keyhole garden for a number of years now and so cannot provide a current cost estimate for the kit. But using your own materials you should be able to construct one for very little investment. |
Tools and Materials List: Tools Power driver padded mallet level scissors small drill bit Materials One keyhole garden kit (ours came from The Keyhole Farm) |
Ordered from The Keyhole Farm, the regular price of the kit is as of 2016, $289.00. Instructions on assembly come with the kit but the basic instructions are to assemble the metal EMT conduit frame and then use the included plastic tie-wraps to attach the ribbed fiberglass panels to the frame. The panels are made overlap by approximately 2″. Once all panels have been attached to the frame, place the composting center piece in the center of the keyhole garden at the apex of the keyhole or notch in the perimeter. Use a water permeable cover on the outside of the wire mesh composting center to keep the planting medium out of the composting center and still allow the compost tea and nutrients from the compost to leach back into the planting medium. Fill your keyhole garden with layers of compostable materials and top the compostable materials with approximately 12-15″ of soil or your favorite planting medium. |
Instructions: The idea behind keyhole gardening started in Africa where a group of missionaries were trying to help some remote local people to become more self sufficient and stable. The geographic area was not conducive to traditional gardening. The soil was poor in nutrients with a lot of rock. There were some trees that had died and were just decomposing naturally. One of them decided to build a raised garden since the topsoil was so rocky and found they could construct the walls of the raised bed by using the rock that was so plentiful at the surface. Since the soil was so poor in nutrients and limited, they took the dead trees, cut them into pieces that they could fill the bottom of the garden (knowing they would eventually decompose leaving their nutrients in the garden) and then use the soil from the area where the rock had been removed from the surface. They understood the soil had to be amended to add the vital nutrients, but with no money to purchase amendments, they came up with the idea of putting a composting ring in the center of the garden and to be able to reach the composting ring, they had to make a notch or keyhole in the bed and thus the keyhole garden was born. The construction of a keyhole garden is based on a six foot diameter circle with a notch or keyhole cut out so that any compostable materials such as left over vegetable parts from preparation and/or not eaten can be thrown into the composting ring. The layering of compostable material at the bottom reduces the amount of planting medium necessary to fill the garden and through its decomposition, return any nutrients back to the planting medium used. The reason for the 6 foot diameter circle is that it was found that the nutrients leaching into the planting medium from the composting ring would not leach affectively more than three feet. Thus three feet from the center creates the six foot circle. When initially filling your keyhole garden with your planting medium, it is recommended that you mound the soil or planting medium about 6-8″ inches higher around the composting ring, sloping it down to approximately 2-3″ from the top of the outer frame. This natural slope accomplishes two things. First since we are desiring the materials composting in the composting ring to leach their nutrients into our planting medium, the natural slope of the planting surface gives a better natural flow of the nutrients to the outer dege of the garden. Also, since the bottom of the garden is first filled with approximately 15-18″ of compostable material, the garden is going to settle as the material in the bottom decomposes. The slope helps to ensure the center of the garden does not sink more than the outside causing the nutrients to collect at the center instead of being distributed throughout the garden. Because of the use of the composting ring and the base of compostable material, keyhole gardens have been shown to be among the most productive small footprint gardens. And since they are approximately 28-30″ tall, you don’t even have to bend over to care for your garden or pick the fruits of your labor. |
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