Unlock the Potential of This Environmentally Friendly Backyard Concept
First made popular in Africa, keyhole gardens are now being used all around the world. Once you hear about how they work and the benefits, you’ll quickly see why.
Keyhole gardens are circular, raised gardens with a path in the middle that allows access to the entire space. Within a six-foot radius, you have your compost pile, your vegetable garden and your water source. A strategic layering system establishes a nutrient-rich base for your garden. The compost basket sits in the middle of the garden, providing nutrients to the plants.
Aside from convenience, keyhole gardens are the most environmentally responsible garden you can use in hot, dry, climates. Additionally, they have the added bonus of delivering a lot of food with very little work because of their compact size.
If you want to give it a try, here are a few basics to get you started.
The site of your garden should be in a sunny location on your property, preferably easily accessed from your kitchen. Next, decide what you want to use to construct the structure. You don’t want to use materials that will decompose quickly. Brick, stone, cedar or locust saplings would all work. You can have an elaborate or simple design—be creative.
Your keyhole garden may need to become taller as your compost basket fills so be sure you keep that in mind and don’t design it too short. Start by making it about two feet high, with the option to make it taller as you need to.
Next, design your compost basket. It should be about two-feet in diameter and a foot taller than your existing exterior wall. A chicken wire basket is sufficient because it’s not solid—the nutrients in the basket need to be able to be released into the garden. Place your composting basket just inside the keyhole.
Now begin layering the ingredients to fill the garden inside the structure:
• The bottom layer should have branches, rocks, or broken clay pots about three inches deep to provide some drainage.
• Then comes your carbon layer, also known as “browns.” Browns are things that used to be alive but are now “dead.” Add a layer of cardboard (TV boxes are great to work with), then straw and/or leaves. This brown layer needs to be three times deeper than the next layer. So if your garden is three feet high make this layer two and a half feet high.
• Next you have your nitrogen layer or “greens.” This can be grass clippings, coffee grounds you’ve collected from your favorite coffee shop, food scraps… anything fresh. (Don’t use all grass clippings here as they may mat and not break down properly.)
• Finally add your soil, about 6 inches deep. Try to fill the soil so that it slopes down toward the edge of the garden. This will help with drainage.
Keyhole gardens are best for greens, radishes, broccoli, beans, etc. It’s not the garden for tall or deep-rooted crops like potatoes. Grow at least four different things in the garden to help use the soil’s nutrients wisely. You could run right out and make the structure out of chicken wire and plant greens in it for fall. Try spinach, kale, turnip greens and chard.
To prolong the growing season, make a “top” out of a floating row cover fabric or a poly/plastic sheet for greenhouse structures and have fresh greens on your table from your garden at Thanksgiving.
You’re probably wondering, “What did I make that basket thing for?” We’re back to greens and browns. Begin filling the compost basket in the center of your keyhole. It is just like a compost pile. Add layers of browns and greens and as the magic of decomposition sets in, the nutrients and moisture released will feed and water your vegetables.
It’s still a good idea to add water once a week if it doesn’t rain. But, you don’t need to drag a hose out there! Did you boil water for potatoes? Dump that in. Cooking corn for dinner? Dump that water into the basket. Use the “gray water” from around your home and save resources. Filtering through the compost cleans it out so it’s safe to use. The compost you are adding along with the gray water will keep the soil fed and the garden productive for several seasons.