Building a keyhole garden

Do you remember those old-fashioned keys, nearly half a foot long, some so intricate they looked like works of art? The receiving side of the lock called to mind the outline of an angel.

When you put the key inside and turned, everything would click into place, and magical doors would open (or at least beautiful, heavy wooden doors that cost a fortune at vintage markets these days).

Now imagine that you are the key and you are standing in the center of that lock. Instead of this being a lock, though, you are in the center of a keyhole garden bed.

From your central position, you can extend your arms and quickly reach the planting areas all around you. No need to walk down long rows, those rows are instead wrapped around you. YOU are the center of your garden!

The bed is raised to either hip or waist level depending on which height is most comfortable for you. No hunching, no kneeling, no kneeboards to prevent soil compaction – just you, standing comfortably, extending your arms, maybe bending just a bit at the waist to plant, water, weed, and harvest.

This bed fits you just like, well, like a key fits a lock – as if you were made for each other.

This, my fellow gardeners (or gardeners to be), is the magic unlocked when you garden using a keyhole style raised garden bed.

Contents

Other Reasons to Build a Keyhole Bed

Besides the comfort of gardening while standing up, and having the garden revolve around you, there are a few other good reasons to try this concept.

1. Vole, mole, gopher, and rabbit resistant

Since your planting area is elevated off the ground, with the right construction, you can minimize or eradicate risks from diggers and ground level garden eaters.

2. You can skip a trip to the landfill

I don’t know about you, but I feel guilty about all the stuff I throw away. When you build your keyhole bed, you can use your unwanted junk as the base for your keyhole bed. (I’ll show you how shortly.)

3. Prevent pathogen problems

If your soil has pathogens, such as tomato or potato blights, those can live in the ground for years – almost ten years in fact. By building keyhole beds raised to hip or waist level and using disease-free soil to fill your bed, you can quickly get back to growing your favorite veggies in your new keyhole bed.

4. Can be built in just a few hours

You can build a keyhole bed that functions as an enclosed garden in just a few hours. Similar to straw bale or other forms of raised bed gardening, you can also build pest protection right into your keyhole bed design, so there’s no need to fence in your keyhole bed.

All you need to do is integrate taller posts into your bedsides and wrap or cover those with fencing, netting, or row covers as needed.

How to Plan Your Keyhole Bed

Now that I have (hopefully) convinced you to try keyhole bed gardening, the next step is to build it.

There are no set rules for how to build this kind of bed. It is all about what works for you and appeals to your design aesthetic. However, there are some necessary steps to go from concept to planting.

Rather than tell you how to do it, I decided to build one to show how easy it is.

Source Materials for Your Keyhole Bed

Since I homestead on a tight budget, I didn’t want to spend any money on this project. So, I started by scrounging materials from around my property. This was the longest part of the process because I had to do an inventory to figure out what I had to work with.

I decided to use these things as my base:

  • A broken picket fence panel (previously destined for the landfill)
  • A few fence stakes that I had on hand
  • Bamboo posts I had cut down in the fall
  • Four-inch diameter poplar posts that I felled with a folding saw for this project
  • A run of 4-foot wide weed mat that I recently pulled from my pathways
  • Rocks, branches downed in recent winds, junk mail, paper feed bags
  • A few cinder blocks we had left from other projects
  • A run of welded wire fence left over from building a duck paddock
  • A few screws and some wire

Believe it or not, this random mish-mash of materials will become the base, walls, and growing area of my keyhole bed.

Choose Your Location

Unless you have long arms or use thick materials to make your walls, most keyhole beds are roughly a 6 x 6-foot square or a 6-foot diameter circle. Choose an area that will fit your bed and has full sun. If your happens to be weedy, mow them down and build right over them.

Bill Mollison, one of the founders of the permaculture movement, and a huge advocate for keyhole beds suggests putting them close to your house. This makes it more likely that you’ll visit your garden often to tend and harvest.

Since your growing area will be raised above the ground, you don’t have to think about drainage in the way that you would an in-ground garden. You do want to make sure you aren’t standing in mud sludge every time you garden. Also, water should drain from your bed without creating a big mess.

Wind protection is also essential for almost any annual garden.

Try On Your Keyhole Bed on Before You Build

Since a keyhole bed is meant to fit you perfectly, try it on before you start building. Mark out your proposed bed area.

Stand in the center and stretch out your arms. Can you easily reach all parts of your imagined growing area? Can you go wider or does it need to be narrower for your arm-span?

Pretend you are watering and weeding. Then decide how high you want your beds raised. I like my beds at my hip level since I hand water daily and that felt easier with a lower bed. If you use drip irrigation or a sprinkler, then you may want your bed higher so that it’s perfect for weeding and seeding.

Imagine yourself gardening in your new bed. How does it make you feel? Warm and fuzzy or exposed? How’s the view?

When I tried mine on, I ended up changing the orientation because I realized I wanted to look out onto my duck pond while I worked. Also, I liked facing my driveway rather than having my back to it.

Build Your Keyhole Bed

I can’t tell you exactly how to build your bed. Part of the fun of this project is figuring it out using what you’ve got.

Construction methods will depend mainly on what materials you use. However, here’s how I built mine to give you an idea of the basic process.

Step 1: Exterior Walls

I set my exterior walls first. My broken fence panel became the front of my bed so that others would see that when they come down our driveway.

I dug my poplar posts two feet into the ground, in the corners, as my anchors. They keep my bed from sliding downhill since I decided to build on a sloped site.

I used four stakes and my bamboo posts to make my long sides. I made a kind of bamboo sandwich by putting two stakes on each side of either end of the bamboo. I also used holes in the stakes to screw the stakes into my anchor posts to lock the bamboo between the stakes.

Step 2: Make the Keyhole

I used a few more stakes and leftover welded fence to shape the interior keyhole area of my bed. After driving the stakes into the ground, I formed the wall into a kind of bulb around where I will stand.

I wanted a solid surface to set my transplant trays, seed basket, or watering can on. I leveled and stacked up a few cinder blocks on the short side of my keyhole area.

Step 3: Make the Base

This is where all your old junk comes in. You are going to stack it up and make a base for your raised bed.

I used downed tree limbs, branches, and junk mail as my base layer. Then I smoothed it out with biodegradable paper feed bags.

My base is almost like a huge mound and will decay over time. I did this intentionally because I only plan to use this bed for a couple of years (because I have other long-term plans for that area).

If you want yours to last longer, use more permanent materials. People have used stacked glass bottles, aluminum cans, polyethylene feed bags, old concrete, broken bricks. You have lots of options since you won’t be growing in this area, you are just trying to build mass up to about 6-12 inches below the top of your bed walls (to leave room for soil).

There are three things you want to keep in mind when building your base.

  1. You need to stack stuff in such a way that water can run through from your bed to the ground and move away from your bed.
  2. You might not want to use toxic stuff because if it does degrade over time, the water that runs through from your bed can wash toxins into surrounding areas.
  3. You want your base to be stable since this is the most “structural” part of your bed and lots of soil will sit on top of it.

Otherwise, cram stuff in place. This is fun, like assembling a puzzle.

Step 4: Make the Growing Area

The one place you will want to use more ideal materials is for your growing area. Whatever you use here needs to drain well and still hold your soil in place.

If you are going to plant perennials in your keyhole bed, you can use less permanent materials for your growing area. Things like cardboard layered thickly or lots of newspaper will work. When these materials eventually degrade, your plant roots will hold your soil in place.

If you plan to grow annuals, you’ll be uprooting plants regularly and adding new soil or compost at times. So, you’ll want to use more permanent materials to make your growing area.

I doubled up a run of weed mat and shaped it over my base and around the sides to create something like a giant growing bag for my soil. Plastic bags with holes punched in for water flow can also work. Tubs with holes drilled for drainage or wooden boxes with space between the slats are also good options.

After I had my weed mat shaped around my base, I added soil one shovel at a time. As I added it, I smoothed out my weed mat and made sure it wasn’t drawing down below the top of the bed.

Step 5: Add the soil

This is the final step before planting. Add the soil, at least 6 inches of soil depth, but more depth is better. I usually opt for about 8-10 inches. If you plan to grow potatoes or sweet potatoes in this bed, go for at least 12 inches of soil for best yields.

I built my keyhole bed in an alluvial area with fertile soil, already fertilized by my ducks. I dug out the native soil before I put down my base and then used that to fill my growing area. If you don’t have good native soil, then buying or making your own potting mixes work great.

I also like to finish my beds with a layer of mulch such as straw or double-shred hardwood. I move this aside to plant then push it back near the plant base as the plant grows. Mulch keeps the soil moist between watering.

What Can You Plant in a Keyhole Bed?

Now, you’ve got your bed built. So what can you plant?

As a rule of thumb, you can plant pretty much anything that you can grow in a 1-gallon container.

Since your bed is already raised, you also probably want to grow things that will not get taller than you can reach. Otherwise, you are taking away the benefits of growing in your easy-to-reach zone.

I love to use these beds for things I often harvest like lettuce, chard, kale, and other cut greens. They work great for annual herbs and cut flowers too. Vegetables that form a root ball like onions, beets, turnips, and round radishes are also good choices.

Bush tomatoes work well. For vining tomatoes, you can build a trellis on the side of your bed and grow your tomatoes up and access them with a footstool.

Or…you can run your trellis outwards like a table and vine your tomatoes over the trellis. You may have to leave your keyhole to harvest, but you keep your tomatoes off the ground and limit fungal risks.

Now, that you are in the know, unlock the magic in your garden and build yourself a perfect-for-you keyhole bed!

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How To Build a Keyhole Garden

Living in an arid climate or an area plagued by drought can make traditional gardening nearly impossible. But with a sustainable gardening technique called keyhole gardening, used in areas as dry as sub-sahara Africa, growing food can not only be succesfull, but one can create a virtual oasis and eat year-round.

A keyhole garden in Africa

A keyhole garden: the ultimate raised bed planter

Frequently referred to as the ultimate raised bed planter, a keyhole garden is a waist-high planter in the shape of a circle, 6 feet in diameter, with a pie-shaped wedge cut away. In the center of the keyhole garden is a hole for a composting basket which continually nourishes the soil and plants. Because of its unique shape and height, the garden requires little to no water throughout the growing season.

Why is it called a keyhole garden? Because if viewed from above, the garden looks just like… you guessed it, a keyhole. The keyhole is meant to provide easy access to the composting basket in the center, and of course, to tend your garden. The design is also convenient for those with mobility problems and those who may have difficulty spending long hours bent over in a traditional garden.

The outer container of the keyhole garden can be made out of any variety of materials that are handy, sturdy and recyclable: native rock, clay, old cement blocks, brick, cedar, bottles, etc. Just make sure that your materials have not been exposed to chemicals which may harm your plants, especially if you’re growing vegetables and fruit.

Experts suggest that the growing medium in a keyhole garden should be mostly compost. The “brown” elements should be materials like cardboard, newspapers, straw, twigs, old leaves and dead plants. The “green” elements should be materials like manure, tea bags, coffee grounds, and food scraps. Because of the size of the keyhole garden, if the browns and greens are added in the correct ratio, the keyhole garden should be ready to plant in only 30 days.

What can you grow in a keyhole garden?

Nearly anything that can be grown in a traditional garden can also be grown in a keyhole garden: onions, garlic, tomatoes, kale, peppers, spinach, carrots, berries, you name it. You’re only limited by the size of the container.

Below is an infographic from Flora Select with instructions on how to create your very own keyhole garden.

What is a Keyhole Garden?

Raised bed gardening is my favorite way to garden. I love the ease of set up, and harvesting is a snap and, if you set your beds upright, there is little weeding to be done. Making a keyhole garden uses all these concepts and more!

Raised beds are nothing new. The idea is to elevate the garden to maximize drainage, improve the soil, and enhance access. Keyhole gardens are a riff on that idea, with one addition: a center compost area that works as a self-fertilizing element for the plants. A salad keyhole garden takes it a step further, by planting specific vegetables and herbs together–to be picked at the same time–to create a delicious dish.

Source: Fix.com

What’s most interesting about keyhole gardens is their bountiful history.

They began as an invention of charitable organizations to help people in developing countries create a self-sustainable, controllable food source. Considering that the construction of keyhole gardens often utilizes recycled materials – think cast-off tin and upcycled bricks – schools in some of those countries use the gardens as a way to both grow nutritious ingredients for school lunches and as a learning tool, for children to take the idea home to their parents. The center compost bin serves a dual purpose: it provides nutrients to the plants and offers a spot for recycling kitchen waste.

One of the biggest attractions of a keyhole garden is its ease of construction. Nearly any material that will withstand the stressors of weather–rock, stone, bricks, metal–will work for the walls. Although there’s no right or wrong height, a keyhole garden typically maxes out at about 6 feet wide, but smaller diameters will work well too. The access notch makes the garden look like a keyhole, and leads to the composting center. That’s often placed on the least sunny side of the bed (usually north), to allow the plants to capture the sun better.

Read the full article with instructions on how to construct your very own keyhole garden HERE

How to Make a Keyhole Garden

Follow these step-by-step instructions to start keyhole gardening.

  1. Gather materials like bricks and rocks to make a circular wall with a diameter of 6 feet and a wall that measures 3 feet in height. This is the key concept to a keyhole garden design.
  2. With the help of chicken wire, make a tube that will serve as the compost bin. Place the tube at the center of the keyhole garden.
  3. Then, take a small section of the outer wall and to form two walls that run to the compost bin at the center. You’ll get the keyhole shape.
  4. Afterward, take some things off your compost piles such as cardboard and other recycled materials of the same nature then layer them in the walls and bottom of the garden bed. Above the layer of cardboard, add organic matter such as grass, plants, twigs and other compostable materials. Lastly, the top layer should of good soil and other composting components. The soil must slope down to the center from the compost bin. This serves as your keyhole composting garden bed.
  5. Continue to fill the compost bin with food scraps like vegetables, coffee grounds or other stuff that can also be considered as kitchen scraps. You can research for more what goes inside the compost bin to make your keyhole garden kit complete.
  6. After a few months, the garden soil may drop so you can add more.
  7. Last but not least, start gardening. Gather your plants or basket of seeds and other essential elements in gardening such as rocks and water.

What Plants Do Well in a Keyhole Garden?

All kinds of plants can be planted in a keyhole garden. But, the best plants would be root plants such as carrots, beets, radishes and leafy vegetables like spinach, lettuce, and herbs. The nutrients and enough water supply would allow them to grow healthy.

What Are the Advantages to a Keyhole Garden?

These are the advantages of a keyhole garden.

  • It adds nutrients to the soil.
  • It retains moisture. When moisture stays longer, it means that the garden requires water less frequently.
  • It lessens the labor of gardening. A raised bed allows for more access to older gardeners because raised bed gardening makes gardening easier for planting, weed control, and harvesting. Moreover, moisture retention means you don’t have to water your plants every day, thus less effort.
  • Low-cost design
  • Vegetable production all year round

Final Thoughts on Keyhole Gardens

Get other companion planting ideas from one of my favorite new books – The Mix & Match Guide to Companion Planting, learn about other Permaculture Principles to use in your yard and review other Drought Buster Strategies.

Have you used the Keyhole Garden concept in your yard? Share your successes (and failures) with raised bed gardening in the comments below.

Craft Your Own Keyhole Garden

September 20th, 2017 Fantastic Team Permaculture Power Post Views: 4,444

If you love gardening, or if you are just starting out, you are probably familiar that healthy gardens and drought don’t work well together. However, what if you live in a dry and hot place? Water isn’t scarce, but not everyone can afford to run water from the hose all day long just to keep a couple of plants alive. Still, there are a couple of compromise options that you can still grow healthy plants in drought and have a garden that’s flourishing.

Keyhole gardening is one of those methods that has been created to grow healthy plants in dry climates. This method uses small and centralised type of gardening that keeps the compost nourished. The biggest advantage of keyhole gardening is that you can save space along with water. Just like growing plants in a container with the added benefit of much richer.

The History Of Keyhole Gardening

Just like every man-made thing keyhole gardening has its beginnings in necessity. And that is the need of people to grow food even when the resources to do so are scarce.

Being a fairly modern type of farming, keyhole gardening was first developed by Send a Cow to help poor African families grow their own food. It turned out to be a very successful experiment and is now taught by various organisations in Africa.
The idea is to teach the kids who then can teach their parents at home how to make a keyhole garden.
Since then this method has spread all around the world, including Texas and Australia.

Keyhole Garden Beds

Keyhole gardens are meant to be designed to save space and to be easily managed. Perfect for small gardens and the hot weather of Australia, this type of gardens are a perfect choice. Depending on the size that you are looking for, they can be made in different shapes, however, the concept stays the same.

Where to make a keyhole garden?

The place where you will put your keyhole garden is very important. It all depends on the plant that you want to grow. Of course, if you want to grow to different types of plants you can make two separate gardens.
According to what the chosen plant needs you can build the keyhole garden in the sun or in the shade. After you’ve decided on the perfect place it’s time to make the garden.

How to make a keyhole garden?

Making the garden itself requires planning. You’ll need basic building skills depending on the material you choose to build it with. Make sure to layout a simple representation of the garden. That way you can better decide if the size is right for the space that you have.
Another thing that needs careful planning is the accessibility. Will the entrance to the structure be enough and can you manage to access the entire area? These are questions that you need to answer when you plan the layout.

What is a keyhole garden made from?

A keyhole garden can be made from a variety of things. The material doesn’t really matter as long as you have a stable structure that will hold together. Materials that can be used to make this type of garden are bricks, wood, stones, cement and anything that you can think of.
With stones being the most common choice in building keyhole gardens, this might be the most suitable and easy choice.

Building a keyhole garden bed

Just like making a raised bed for a normal garden, you can make a keyhole garden. It does require a bit of understanding, but in general, it’s not a tough process. We went through planning, positioning and all that, so now it’s time to make the structure itself.

The structure of the keyhole garden consists of 3 different segments:

  • The Walls
    Building the walls is the first step of the process. As we mentioned above, you can use numerous materials for it. Make sure to build a solid structure that will be able to keep the soil in place and retain the moisture. It needs to be strong enough to contain the weight of the soil even when soaked.
  • The Core of the Keyhole Garden
    Having а well build core is mandatory if you want your garden to flourish. This is the place you’ll use as your compost bin. In the core of the garden, you can throw any organic rubbish that will benefit your garden.
    It’s best to use a meshed material, that will keep a cylindrical shape or a tower of sticks if you want to go completely organic. Before you put anything in the bin make sure to make a layer of stones at the bottom that will serve as a drainage.
  • The Mounted Drainage of the Inner Layer
    After you have built the walls and the core it’s time to take care of the drainage of the garden. Being one of the most important things, it’s important you don’t skip this step. Lay a layer of stones, sticks and wood that will serve as the drainage for the main planting place. It’s best to make this layer in a conical shape so the compost tower is higher than the rest of the garden. This will run the water equally when you pour it in the centre.
  • The Inner Layer
    This is the place where you will plant your plants. Fill it with soil that will be right for the plants that you are planning to grow. Make sure to compost heavily, because you need a nutrient-rich soil.

Keyhole garden beds

Just because they are called keyhole gardens it doesn’t mean that you should stick to the keyhole shape. You can apply the philosophy of this type of gardening to any shape. Although, round keyhole beds work best because the distribution of the compost that you will store in the core.

How can your garden benefit from a keyhole garden?

If you are looking for a way to have a flourishing garden in a compact space, utilizing this type of gardening might be the best choice for you. Make sure to pay close attention to your compost because you’ll need healthy soil. Maintain the right amounts of pH, moisture and light requirements your produce will need to grow healthy.

DIY Illustrated Permaculture

First made popular in Africa, the keyhole garden is catching on in Texas and other hot, dry places. A keyhole garden holds moisture and nutrients due to an active compost pile placed in the center of a round bed. Although most helpful in hot and dry locations, a keyhole garden will improve growing conditions in just about any climate.

How a Keyhole Garden Works

A keyhole garden is a round garden bed with a compost pile in the center. The garden has a notch in the front, so gardeners can easily add to or turn over the pile. Featuring a drainage layer, a soil layer, and a planting area, keyhole gardens combine all the necessities that plants need to thrive.

From a bird’s eye view the garden is shaped as a keyhole. A notch is cut into a round garden bed. The notch makes for easy access to the center compost well.

Keyhole garden in Uganda by Send a Cow.

This sustainable gardening method uses kitchen and garden waste and gray water (or wash water) as food for your garden.

Layering is proven to enhance soil health. Layering suggestions from Texas Co-Op Power: Wood on very bottom, next cardboard, next a bit of compost, next petroleum-free newspaper, manure, worms, wood ash, straw, topsoil. Repeat, compost, straw, topsoil or some such combination until you reach desired height.

When it rains or when you water your compost, the nutrients will seep into the surrounding bed. During rainy spells you might wish to cover the compost so the nutrients in the compost do not leach out too rapidly.

Felco F-2 Hand Pruners

Whether your garden is round, square, or keyhole, these pruners will become one of your favorite tools. The handles are forged aluminum, the blade is hardened steel. The handle even includes small shock absorbers to protect your hands and wrist. Simply the best on the market—and it comes with a lifetime guarantee.

Buy for $43.90


Keyhole gardens have been made popular by Send a Cow, a humanitarian aid organization which builds keyhole gardens for families throughout Subsaharan Africa. Three keyhole gardens can supply a large family with all their vegetables for a year.

29 Outstanding Keyhole Gardens Around the World

1) Keyhole Garden With A Frame


At Keyhole Garden in Central Texas, Deb Tolman uses keyhole gardens as the main source of her own food supply, and is working on ways to keep them producing throughout multiple seasons and conditions. Dr. Tolman incorporates a frame into most of her designs to support a shade cloth during the hottest months. The frame might also be covered in early spring with plastic sheeting to create a greenhouse. Dr. Tolman is available for workshops, consultation, and seminars. Photo by Dr. Deb Tolman.

2) Lesotho Keyhole Garden


Keyhole garden in Lesotho by Send a Cow, which first popularized keyhole gardens in Africa. Send a Cow has helped countless families and schools build keyhole gardens.

3) Garden From Colorado

A keyhole garden in Colorado. This one is six feet in diameter. The homesteader used three layers plastic milk cartons filled with dirt to form the garden wall. She rolled together hardware cloth to make the center area for compost. Then she layered, first with rough organic matter such as pine needles and bits of wood. In compost basket, she put decomposing leaves. She didn’t add kitchen scraps because at the time she built it, bears in her area were just coming out of hibernation! Later she added black plastic to prevent leaking from the cage when she watered.

4) Edible Estate Garden

The keyhole garden was only one part of large renovations to the property. Casey Boyter Gardens designed this garden with the family’s love of entertaining in mind.

5) Low-Bordered Keyhole Garden


This keyhole garden by Send a Cow looks easy enough to set up, but the bricks do not look like they will take another level if you want to make it bigger someday. The compost adds more and more soil year after year.

6) Keyhole Garden With Center Well

In this keyhole garden by Send a Cow, the builders have lined the center well with sticks, or with chicken wire lined with straw, to separate the two areas. The center well is used to irrigate the whole garden, bringing nutrients from the compost into the surrounding soil.

7) Dry Stack Wall Garden

A keyhole garden in Ethiopia. Keeping a lid on the center well will retain heat and reduce evaporation. Photo originally found on “dsnyderphotography.com/gettign-it-write-continued,” visit dsnyderphotography.com for more information on David Snyder.

8) Keyhole Garden In Rwanda

Keyhole garden in Rwanda by Send a Cow.

9) Garden Made Of Cement And Glass

Keyhole garden a’la” Paseo #permaculturedesign #keyholegarden #bohollife

A post shared by Jesse Acebes (@paseodelmarbohol) on Feb 4, 2017 at 2:39am PST

The borders of this keyhole garden are made of cement and glass, eliminating the need to worry about compost eroding the garden walls.

10) Flourishing Keyhole Garden In Lesotho

Keyhole garden in Lesotho by Send a Cow. Found from www.sendacow.org

11) Garden In Uganda

Keyhole garden in Uganda by Send a Cow.

A Rooftop Keyhole Garden

Yes, you can build a keyhole garden on a rooftop. This bed has squash and tomatoes. The exterior is made of rocks. The center area is a Smart Pot Compost Sak, a reusable but porous container.

12) Keyhole Garden From Sticks

Keyhole garden with a surround of sticks in Uganda by Send a Cow.

13) Overflowing Keyhole Garden

Keyhole garden by Send a Cow.

14) Keyhole Garden With Compost

Keyhole gardens wrapped in wood, by Deb Tolman of Texas. In the winter the compost in the center of the keyhole garden generates heat and holds moisture. See the Keyhole Gardens Facebook page.

Introduction To Building A Keyhole Garden

This introductory video explains why a keyhole garden is especially good in the hot, dry American West and South. Then, it shows in time-lapse format how to make the garden. After using marking tape to outline the shape, pile bricks three feet high for the exterior wall. Line the inside surface with cardboard. Make the compost bin with 2 x 4 wire, about one foot in diameter. He then shows how to layer and form the soil.

15) Raised Bed Keyhole Garden

The arrangement of these gardens is stylish and functional. The owner mentioned that the design incorporates a 3 foot walkway around the center garden for comfortable access to every plant.

16) Garden Using Straw Wattle

Keyhole Vegetable Garden by Anne Hars, lined with straw wattle.

17) Keyhole Garden Made By Students

Keyhole garden by sixth grade students in the UK, who had been learning about sustainability and the soil conditions in Africa. The children used a combination of bricks and stones to create the garden. They surrounded the center compost with a piece of willow fencing. A garden sieve was then placed on top of the compost area to allow the rain water to seep through the compost and into the garden to help enrich the soil. Each day children throughout the school place their fruit scraps and more into the compost. The children used the proceeds from selling their produce to help buy a goat for a third world country through OXFAM.

18) Florida Garden Made With Bricks

Keyhole garden in Florida by Melissa Contreras. This garden can grow in height, as the compost adds volume, more bricks can be stacked as in the image below.

19) Desert Garden

This homesteader has two fences to keep pests from invading their garden. The walkway is longer than most keyhole gardens, allowing for better access to plants.

20) Freddy Hill’s Keyhole Garden

Keyhole garden by Freddy Hill of Oklahoma. Freddy wanted to build a keyhole garden after being fascinated by their use in arid places.

21) A Productive Keyhole Garden

Keyhole garden in Texas by Deb Tolman. Says Deb: “If all the layering guidelines have been followed, watering is at a minimum, evaporation is at a minimum, all plants look nutrient-fed, and productivity is high.”

22) Steel-Walled Keyhole Garden

These designers used steel for their raised keyhole garden. The steel is a good option for colder climates because the material retains heat.

Keyhole Gardens Explained By Doctor Tolman

This video shows Deb in action, piling pounds and pounds of wet cardboard for the filling of the garden. She is demonstrating at one of her keyhole garden classes. She says: “You will always get beautiful soil and good-looking plants, because they’re exposed to compost, and a good balance of microbiology.” Kids help out with piling cardboard, leaves, magazines and dirt to form the base of the garden. The exterior of the garden is made with cinder blocks. The video also shows Deb’s homestead, where she experiments with gardening ideas. Deb (who has a Ph.D. in Environmental Science), says that anything can be grown in a keyhole garden, even trees. The “key” to the keyhole garden is the compost that retains moisture and creates healthy soil. The soil is key. “The health of the soil predetermines how water moves. It predetermines how healthy your plants are. Healthy soil begets healthy plants which begets healthy animals which begets healthy people. It’s all very connected.:

23) Morena’s Garden

Keyhole garden by Morena Hockley.

24) Preparing Garden Soil With Compost

Keyhole garden in Texas. “Layered in the bed are bones of two cows, ash from one brush pile, aged dried poop from a dozen cows, five bags of clover, a pile of forest floor mulch, cardboard, rusty items, and 15 buckets of two year old compost.”

25) Wine Bottle Garden

The reuse ideas are endless—cans, metal, old row boats…earthbags…logs. This is a wine bottle keyhole garden by Mary Martine of Phoenix. “800 wine bottles, one year from conception to completion, and a lot of faith that this crazy idea would work. The diameter of the circle is approximately 7 feet.”

26) Beer Bottle Keyhole Garden

Beer bottles in cement. No keyhole. Love the bottle reuse, looks sturdy. Frame is for a shade cloth. Via www.facebook.com/keyholegardens

27) Garden With Walkway

Keyhole garden by Jim. Via www.organicgreendoctor.com

28) Large Keyhole Garden Array

Vegetable garden complete, ready to be planted! Harper Atelier, Prague #kitchengarden #keyholegarden #vegetablegarden #garden

A post shared by Dana Harper (@dana.r.harper) on Apr 28, 2017 at 12:09pm PDT

In Prague, this keyhole garden is being used to grow vegetables.

29) Keyhole Garden In The United Kingdom

A keyhole garden built by students in the UK. Flowers surround the vegetables. Via Send A Cow.

African Style Raised Keyhole Garden

This video from the non-profit Send A Cow shows, step-by-step, the construction of a keyhole garden in Uganda. It lists the materials needed: Cleared ground near a kitchen, bricks or stones, topsoil, compost, straw/leaves, wood ash, sticks, and string. Then it gives specific instructions for laying out the area (all you need is sticks and string to measure a radius). The video shows a group of local women tilling the soil, building the foundation of the garden from the bricks, building frame of the garden out of sticks, and then filling it with help from their daughters.

How To Build A Keyhole Garden (Parts 1 & 2)

Here in part one, host Casey Hentges shows the finished product and explains the keyhole garden concept. Next, she shows the materials to use—straw, leaves, raked grass, branches, compost, old cardboard, and some animal bedding that will add nitrogen to the compost. She shows the tools necessary, which are pretty simple: just a box knife, a tape measure, twine, and marking tape to mark the perimeter of the garden. She shows how to measure out the garden, then explains the considerations behind the size of your center cage. She lays out the exterior of the garden, including the keyhole.

In part two, we see the filling of the garden. Because she is building atop grass, she recommends setting cardboard over the grass to keep it from growing in the bed. This serves the same function as weed fabric, but will decompose and add nutrients to the soil. Cardboard also retains water well. Sticks form the next layer. She recommends 1/2 inch to 1 1/2 inch branches—anything larger may not decompose as well. Next up, leaves and other dead plant material. Next, a layer of nitrogen-rich animal bedding, and a final layer of dead grass. Finally, six inches of top soil that you’ll be planting on. Water in-between each layer–this helps start the decomposition process. Berm the soil, with the highest point at the center of the bed. This will help the compost flow toward the edges of the bed. The last step is putting compost in the cage area. Again, it’s layered—first with food scraps, then shredded paper, then green cuttings. Water again. Now you’re ready to plant!

An Oklahoma Keyhole Garden

Jim Long shows how he built his keyhole garden, with wooden fencing as the exterior. He shows the filling he used beneath the soil. The round hole where compost and water goes is made from chicken wire. He places a lid on top of the round hole to help retain some of the moisture. Jim saves the compost to use in other pots and future use in his keyhole garden.

The Best Keyhole Garden And Small Garden Books

Plant Your Garden In A Keyhole by W. Leon Smith

Soiled Rotten: Keyhole Gardens All Year Round by Deb Tolman, Ph.D.

The Quarter-Acre Farm: How I Kept the Patio, Lost the Lawn, and Fed My Family for a Year by Spring Warren

Gaia’s Garden: A Guide to Home-Scale Permaculture by Toby Hemenway

Resources For Building A Keyhole Garden

Sloping the soil away from the center well allows better transfer of water and nutrients and adds to surface area. www.sendacow.org.uk

A two-page, printable, very visual, keyhole garden building guide from Send a Cow. Bright, colorful, good for kids.

A visual but slightly more dry two-page printable keyhole garden building guide from the Baker Institute.

Photos and a 10-step keyhole garden building guide from Texas Co-Op Power.

Written instructions on how to build a keyhole garden from TECA, a program of the Food and Agriculture Organization of the United Nations.

KeyholeFarm.com sells a keyhole garden kit, starting at $289.

Keyhole Gardens: A Drought Tolerant Composting Garden

Whose Crazy Idea Was This?

The keyhole gardens are the brainchild of humanitarian charities and missionaries for use in impoverished countries with poor soil, bad weather, and starving people. At least one organization teaches the schoolchildren how to construct the gardens from available recycled materials and to care for the vegetables. The schools then have nutritious vegetables for lunches. The children are encouraged to build a keyhole garden at home to educate their parents, thus enabling families to feed themselves. Advisers visit with the families to trouble-shoot garden problems.

Keyhole Garden Concept

The Keyhole Garden concept is brilliantly simple. A circular raised bed has a center compost basket that distributes nutrients to the surrounding lasagna-style garden bed. A small pie-slice section of the bed is used for easy access to the center compost basket forming the keyhole design (click the sketch on the left for larger image).

Kitchen and garden waste, along with household gray water, are added to the center basket. The soil bed layers are slightly sloped away from the center to aid water and “compost tea” distribution. As the materials decompose, soil, composting materials, and amendments are added to the bed in later growing seasons.

Keyhole Garden Benefits

  • Center compost basket provides a steady supply of plant nutrients and amendments
  • Uses less water with mulching and moisture from center basket; drought-tolerance
  • Depending on outer wall materials, soil can be warmer than traditional raised beds
  • Garden can be modified per owner’s needs, like child or handicap accessibility
  • The short bed distance (from outer wall to center basket) is easy to tend
  • Gardens require a small area, a maximum of 6-1/2′ (2 meters) diameter
  • Recycled material use makes the gardens inexpensive, or free, to build
  • The raised design removes threat of trampling by pets and humans
  • Saves steps by adding garden waste to the handy center compost basket
  • Keyhole Gardens can be made temporary or permanent
  • Keyhole Gardens can be an attractive feature with a good aesthetic design plan

Keyhole Garden Construction

This is not a comprehensive how-to. If you would like detailed information to construct a Keyhole Garden, please follow the links provided at the end of this article, otherwise, refer to the Cross-section View A-A at left (click for a larger image).

The following is a list of recurring points made for the garden design to work efficiently. Use whatever materials you may have at your disposal that will allow the best result to be achieved.

    Materials:

  • Drainage: Rocks, broken tiles or pots, rusty cans, twigs, small branches, or old critter bones can be used for the bottom drainage layer.
  • Compost Basket: A tube, 1′ to 1-1/2′ (.5 meters) in diameter and tall enough to extend well above the center of the bed, can be fashioned from anything that will allow water to pass through into the surrounding bed like chicken wire, fencing, or sticks (think in terms of a woven basket). Supports to hold the basket in place, such as strong branches, boards, or rebar, and wire or strong twine to hold everything together, also, will be needed.
  • Outer Border Walls: Anything that will contain the soil could be used: stones, bricks, or blocks can be stacked into place; boards or branches could be driven into the ground; sand bags or old tires could work as well.
  • Planting Bed Fill: Use the same materials as for a lasagna garden, or compost pile, such as cardboard, paper, manure, leaves, straw, hay, old potting mix, or wood ashes, then finish the surface for planting with top soil.
    Layout:

  • A cleared level area no larger than 6-1/2′ (2 meters) in diameter is the maximum size for a Keyhole Garden. A larger diameter bed may suffer from a lack of water near the outer wall of the bed (from the compost basket), and plants close to the center may be difficult to reach.
  • The cutout area of the keyhole should be wide enough to allow easy access to the compost basket when adding materials, removing compost, or making basket repairs if needed. Positioning the cutout on the North side of the circular garden would use the dark space of the bed that would not receive full sun, thus leaving all the sunny sides for planting.
  • All the layers added to the bed should slope downward to the outer border wall. The slope helps direct moisture from the compost basket out into the bed.
  • The outer border wall can be as high as needed for the comfort of the gardener and the amount of sourced materials. The top surface of soil should stay below the outer walls to contain rainwater and prevent the soil from running off.
    Other Considerations:

  • A roof can be made to deflect excessive rain from the compost basket or to conserve compost moisture during drought.
  • Trellises could be installed to support cloches for weather protection.

I have been gathering information and materials to construct a Keyhole Garden for a garden project next year. I was so excited by the design idea that I decided to share the information now, instead of waiting until I could build one to write about later. I hope I have provided a potential new garden concept for others to consider as well.

Additional Information

  • Texas Co-op Power: Keyhole Gardening: Unlocking the secrets of drought-hardy gardening, by G. Elaine Aker; Issue: February 2012
  • Valhalla Project: videos and photos
  • Send-A-Cow: Keyhole Gardens and many other great frugal gardening ideas

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