Keyhole gardening is a technique where you build an all-in-one system that includes a compost bin planted into the center of a raised bed. This compact and efficient system gives you the best of both worlds and is remarkably easy to start.
You probably already know that compost is good for your garden. It is a great way to reclaim nutrients from vegetable scraps and plant waste and add these nutrients to your garden for a powerful nutrient boost. If you have your own system, this offers another practical way to use your scraps.
Anyone with a home compost bin probably has a story about amazingly healthy and robust volunteer seedlings growing in and around their pile. This is because they are growing directly out of, or very close to, a nutrient-rich base. Imagine if you could harness this power right in the middle of your garden.
Perhaps you’ve heard of keyhole gardening and are curious to learn more about it, or possibly this is a new concept for you. Whether familiar or new, keyhole gardening offers several distinct benefits if you’re willing to give it a try.
Join us as we explore seven benefits of keyhole gardening and how you can use this technique to boost your garden’s productivity with minimum effort.
It’s Convenient
My current garden layout works but is far from convenient. My compost is in the back yard and my vegetable beds are in the front yard. When I transfer the aged amendment to the soil each spring, I have to walk around the house and through two fences and two latched gates. I have this inefficient system because of several factors, including animals, very limited sunlight, available space, and neighborhood homeowner regulations.
Keyhole gardening would allow me to decompose organic matter in the center of my vegetable beds and I would never have to walk back and forth toting buckets around my yard. If you have the ability to combine your beds and your compost, this is an extremely convenient setup. Crops can take the nutrients straight from the decomposing organic matter, saving you time and energy.
Space Saving
A keyhole garden is a type of raised bed, and by nature, raised beds are already highly space efficient. You can pack a surprising amount of goodness into a small plot. A typical size is just six feet in diameter. This allows you easy access to your plants and decomposition bin while also keeping all the plants close to the central system.
If you maintain a separate compost pile, you’re probably using more space than the average key-shaped bed. Some systems involve elaborate, multi-step processes that can occupy valuable space.
If you are generating and managing large amounts of organic matter, this can be a great system, but if you have only modest kitchen scraps, you can compost in a much smaller area.
The cage in the middle can be relatively small. If you produce more compost than you need for a single bed, you can set up a separate pile as a secondary site or establish multiple beds.
Time Efficient
If you’re managing a large pile, you’re probably spending time turning, balancing, separating, and moving your organic matter from one place to another. Keyhole gardening allows you to manage a small pile right in the center of your landscape. You won’t have to process and lug material from your pile to your beds because your setup will be all together in one convenient location.
Want to save time? Create a keyhole where your growing space and decomposing organic matter are automatically part of the same system!
Increased Productivity
Plants love nutrients, and they’ll let you know when they need more. Signs of nutrient-deficient plants include poor growth, pale leaves, and low productivity. Plants are always sucking nutrients from the soil, as this is part of their natural growing process. If nutrients aren’t replenished, plants will eventually suffer and start to look and act weak.
Why wait until your plants are showing signs of distress? With an on-site decomposition setup right in the middle of a small area, the naturally slow decay and release of nutrients will keep your soil growing strong all season long.
Flexibility and Versatility
You can grow just about anything in a raised bed, and therefore, you can grow just about anything in this style of bed: Herbs, annuals, perennials, flowers, or vegetables.
You’ll generally want to grow smaller plants in a raised bed or smaller plot, so save your trees, shrubs, and giant pumpkins for a different area of your yard.
You can quickly turn over your bed from one season to the next. Grow salad greens in the spring, warm-season annuals in the summer, and mums in the fall. You can also grow perennial wildflowers or herbs year-round for a long-term arrangement. The choice is entirely yours so you can grow the assortment of plants that best suits your interests.
You Can Build One Anywhere
Just like a standard raised bed, you can build a keyhole garden anywhere. You are essentially creating an entirely self-enclosed system so you can on top of soil, sand, or gravel. You’ll just need a sunny plot with a fairly level surface for the base and then you can build up from there.
This method isn’t just practical; it’s also attractive. You can build a decorative outer wall from pavers, bricks, or stones. You can also create one with wood, such as logs or cut boards. Feel free to be creative with your wall materials. Just make sure the walls are sturdy enough to contain your soil and plants.
It’s Sustainable
Sustainable growing and permaculture are terms used to describe techniques for a long-lasting plant system that works in harmony with the environment. In short, your keyhole garden has a built-in nutrition system that creates a sustainable system in which your plants will flourish from one season to the next.
You will still need to provide the nutrition (regular addition of organic matter) and water. You’ll also need to do the usual maintenance, including pruning, weeding, thinning, and harvesting, depending on what you’re growing.
If you create a healthy system, your plants will thrive. Flowers will be vibrant and abundant, vegetables will be healthy and vigorous, and herbs will be delicious and long-lasting.
Frequently Asked Questions
You can make a simple keyhole garden compost bin with wire mesh. This is a simple cylinder that allows you to fill the center with compost which will slowly decompose while the nutrients freely seep out through the mesh and into the surrounding soil. Your mesh cylinder should be open on the top to allow water and air to flow through.
The cylinder is generally between 1.5 and 2 feet wide, but no wider than 3 feet across, depending on the size of your garden. Don’t use a standard plastic composter for a keyhole garden. This solid material won’t allow enough water, air, or nutrients to flow freely from the bin to your garden. You’ll also need to leave the top open to allow rainwater to moisten the compost and speed up the breakdown process.
When you first build your keyhole garden, your compost bin is set into the bed and extends from ground level to above the soil level at the top of the bed. You will fill this with compost, including kitchen scraps and leaf matter, to the upper soil level.
As the compost breaks down and sinks, add fresh compost. Your compost level should be at the top soil level or a little above. You don’t want your compost to be spilling over the top and through the sides, and you also don’t want it sunken well below the surrounding soil surface. Try to keep the compost at least level with the surface of your raised bed.
When watering by hand, water it directly on top of the compost in the middle of your garden. The water should then run through the compost and disperse into the garden on all sides. This way, every time it rains and every time you water, nutrients from the compost will trickle out into your garden. Since a keyhole garden is relatively small, you should be able to help direct some of the runoff to all areas of the bed.
Keyhole gardens are typically round with a composter embedded in the center of the circle. To easily access the composter, there’s a notch in the edge wide enough and long enough for you to enter and reach the composter. When viewed from above, this arrangement slightly resembles an old-fashioned keyhole!
