I live in the Western United States and I come from several generations of gardeners. I am always on the lookout for good gardening ideas and tips. One kind of garden that has intrigued me since learning of them is a keyhole garden. It really looks like a great idea and could solve quite a few issues that we have in the west with water usage, land usage and crop productivity.
A keyhole garden is a raised bed garden that is usually shaped in about a 6-12 foot circle with a center basket where table scraps and vegetation can be composted and fed to the garden. There is an access path into the center so from a top view it looks like a keyhole.
Layers of compost, cardboard, phone books, and manure are used. In the center you can put in all your table scraps to have them composted and utilized in your garden.
The benefits are that you can easily compost your table scraps, have easy access to all your vegetables, can grow a ton of crops, and conserves water.
The idea of a keyhole garden sounds really great for many situations. In the West water is becoming increasingly a concern. Many areas in the West have had years of drought. There is increasing demand on water resources, due to all the land development for homes and businesses. We are needing to think of different ways to conserve water and use it more wisely.
There is also increasing competition for good arable ground. Sadly much of the good farm land is being used for home and business development. Larger plots of ground to be used for gardens and farms are becoming fewer and farther between.
Alternatives are becoming increasingly necessary to grow gardens and have them be productive. A keyhole garden is a good way to address the issues of space, water use, and fertile ground.
History of a Keyhole Garden and where it is used
Keyhole gardens were made popular in Africa. The super dry arid ground is challenging at best to grow a garden. The keyhole garden was developed to use water wisely and develop fertile soil for gardens to flourish.
In Africa the keyhole gardens and located near the kitchen. Kitchen scraps are put into the center of the garden and become compost to feed the rest of the garden. Often the greywater from the kitchen will be the source of irrigation for the garden. It’s pretty ingenious to use everything so efficiently to get such great results.
The concept of a keyhole garden is now branching out worldwide. It’s been embraced in the U.S. where similar challenges of water and soil to Africa can be found, and has been very successful.
As the concept of Keyhole Gardens is going around the world adaptations are beginning to show up. So a Keyhole garden is something that you can tailor to your needs. It can be used in many environmental conditions besides the harsher arid ones.
Benefits of a Keyhole Garden
There are some really great benefits that are found with keyhole gardens. One great advantage is that they don’t take up much room. On average they are about 6-12 feet in diameter and about 3 feet tall. You can also adjust the size to whatever you want, but this size seems to be the most efficient.
A keyhole garden can be constructed from whatever you have available to work with. You can use rocks or stones that occur naturally on your place. You can use tires, broken concrete, rammed earth bags, bottles, etc. You can also use retaining wall bricks, wood panels, or cast concrete for a more finished look if desired.
When growing a keyhole garden you can minimize use of water and fertilizer. It creates a more efficient garden. As many know, efficient use of water is becoming increasingly important.
I’m not sure greywater from the home is a legal option in all locations. You may need to research what is allowed and what is not where you live. For those places that can use greywater it is a huge saving on water that has already been used once and can be used again.
Composting your table scraps is easily done with a keyhole garden. Instead of throwing you scraps away, or grinding them down the garbage disposal, you can use your table scraps as a resource to grow vegetables.
Crops to use in a Keyhole Garden
A keyhole garden is generally planted with vegetables that don’t take up much room. You can plant intensively and densely to get a great yield. Many of the typical plants used in a keyhole garden are:
Leafy greens:
- -lettuce
- swiss chard
- arugula
- spinach
- cabbage
- kale
- kohlrabi
- cellery
Root crops:
- onions
- carrots
- garlic
- raddishes
- beets
- parsnips
- leeks
Herbs:
- parsley
- oregano
- basil
- mint
- sage
- rosemary
- thyme
- comfrey
- lavender
- chives
- anise
- dill
Some people choose to have their garden to have a theme. For instance you can have an herb only garden, or a salad garden focusing on stuff for salads, or even a flower garden. If you have a garden located right outside your kitchen you can have fresh stuff to eat all the time.
Limitations of a Keyhole Garden
As with everything there are some limitations to a keyhole garden. The major limitation is the types of plants you choose to grow in them. Plants that take up large areas to grow might prove to be challenging in a keyhole garden. Tomatoes, cucumbers, squash, corn, and pumpkins could be difficult. I am sure that they can be grown in them, but it will take some planning.
It can be a bit of a chore to get a keyhole garden set up. You have your work cut out in laying out a retention wall. You also need to create a center basket for composting. You have to haul in the materials to create the bed of the garden. If you are not interested in a little hard work invested for a big return this may not be for you.
How to build a keyhole garden
When constructing a keyhole garden using what you have around you or what is available has been the design of choice. Necessity has been the mother of invention with these. You can use new materials from the hardware store, or just put to use what you have already available around your house and neighborhood.
Measure out a base of 6 feet. In the center you have a receptacle for the composting scraps. The center basket can be made out of screen material, a barrel with the sides perforated, sticks, or buckets that are perforated. Necessity is the mother of invention here.
There needs to be a slight slope from the middle of your garden to the outer walls. The way it receives water and nutrients is from the center and it wicks or leaches outward to from the center.
You mark out a path to the center on one side. Build up the sides to the height that you would prefer. Generally they are around 3 feet, or one meter tall. Keyhole gardens can slope down to no wall on the outer edge as well. It just depends on your wants and needs.
You can vary the size and shape of your keyhole garden if you want to as well. Some prefer a rectangle, oval, or a more organic shape. The circle will be the most effective as far as efficiency of distribution of water and nutrients from the central feeding basket to the outer edges.
Once you have the walls build up start the first layer. The first layer is the drainage layer. You can use rocks, gravel, chunks of concrete, etc. Having larger rocks and stones near the center with allow for better drainage. Without proper drainage you can end up with a swamp of yucky smelly stuff that won’t grow much at all.
Next you build up the bed by layering compost and soil and fertilizer. This is where some have incorporated the use of cardboard, phone books, magazines, etc. Layering the cardboard and such with soil and fertilizer will add a great water and nutrition storage system. This is where some gardeners find that cardboard is really beneficial to the garden, and with all the online shopping cardboard is readily available.
The top layer is the soil that you plan your seeds and plant in. You may want to add a cover to the center. You can keep animals from falling in and getting stuck. You can reduce the evaporation of water by having the center composter covered. You do need to still have air flow to the compost, so don’t put a air tight cap on it.
Using your keyhole garden
Once you have your keyhole garden set up, using it is pretty simple. You dump table scraps into the center and water it in if you need to. As the center scraps decompose it turns into compost and feeds the rest of the garden.
Some gardeners have found that adding earth worms to the compost helps even more. Earth worms speed up the composting as well as creating fertile soil. The worms also add oxygen, loam, and beneficial bacteria to the soil.
