A garden that never needs weeding! Deb Tolman on keyhole gardens


You know you’re in for something out of the ordinary when the materials needed for a gardening workshop include phone books, clothing, leather items, junk mail, donkey manure and grass clippings.  Grass clippings makes sense, but clothing?  Junk mail?  Really?

Deb Tolman, the woman behind that eyebrow-raising materials list, will be leading this Saturday’s Keyhole Garden Build + Feast DIY Sustainability Workshop at The Plant in Pittsboro, from 2-7pm.  Deb, a seasoned landscape designer, scientist and educator, has made a name for herself by innovating and championing sustainable gardening and building techniques.  She comes to us from her home state of Texas this weekend to demonstrate how to build her ingenious, many-layered, and easy to maintain brand of keyhole gardens.

We caught up with Deb earlier this week, to find out what’s in store for this weekend, and to find out a little bit more about the woman behind the phone books, leather items and donkey manure.

We’re so excited you’ll be coming through town to teach this special workshop on building keyhole gardens. Can you please explain what a keyhole garden is, for our readers? 

A keyhole garden is nothing more than a raised, round, six foot diameter garden with a keyhole notch to access a center basket that holds all kitchen scraps. They’ve been used for years in Africa to help locals reclaim gardening space due to desertification issues.

How is what you’re doing with keyhole gardens different from the traditional African version?

What I bring to the table is the same garden shape but with a completely different method, and a whole lot of science.  That method includes absolutely no soil but instead nature’s 3:1 ratio of browns to greens, namely cardboard and other browns, for carbon, and manure or other greens, for nitrogen.

And then by arranging thin layers and planting with tons of plants packed over the top, the same day you finish layering, you create a self-fertilizing and self-watering garden.  It completely takes the guess work out of gardening.  You are essentially recycling, hot composting, and gardening in one fell swoop.

I’ve also added a rebar bonnet over the garden, which adapts it to a greenhouse during the winter months.

Why is a keyhole garden always six feet across?

The science behind it requires six foot diameter.  I go into more detail about this in the workshop.

Illustration from Texas Co-op Power Magazine
Illustration from Texas Co-op Power Magazine


I like that these walled gardens require less weeding than other types of gardens. In North Carolina, the crab grass can infiltrate almost any type of garden – even raised beds – but I bet it would be foiled by high walls. Besides minimizing weeding time, what are other benefits of keyhole gardens?

The benefits are infinite once you see how plants respond to a full volume of some of the best compost in the world.

Plants are bigger than what you normally see, really big.  There are no weeds because the annuals you plant take full advantage of having such lovely soil.  And due to that lovely soil you have more resistant and resilient plants, more capable of fighting off insects and stress.  Oh, and there’s no bending over.

Also, the raised aspect of these gardens keep such a large volume of compost well-contained whereas traditional organic gardening out in the field is lost after a season or so.

What do you usually make the walls out of? 

I tell folks around the country that the wall can be made of anything (usually the material and height depend on what predators you have around) and built at any time, but when you start the filling process, you have to be quick.

Would a person usually use only one of these gardens in their yard, among other types of gardens, or would they maybe create a sort of polka-dotted lawn, sprinkled with numerous keyhole gardens?

I now have 15 keyhole gardens at my house, and I have built for others as many as ten in their front yards.

What will participants be doing at the Keyhole Garden Build + Feast?

In my workshops we end up first building the garden wall, then filling it in with all the non-soil materials, in their correct proportions and layering order, then designing and planting the vegetables, constructing the bonnet for the greenhouse effect, and discussing microbiology, critter control, horticulture, and composting in general.  Then at this particular workshop, we will celebrate afterwards with a feast!

Other than keyhole gardens, what other sustainable gardening or building practices do you teach people about?

My whole life is built on sustainable practices that started with coaching folks through the landscape design and implementation process of gardening.  Now I teach workshops on a lot of subjects, such as:  Cheese Making, Landscape Design & Lasagna Gardening, Sustainable Wildlife Habitat, Holistic Range Management, Earthen Ovens, Cob Garden Benches, Composting & Vermiculture, Greywater Recapture, Drip Irrigation, Aquaponics: Grow Tilapia, Earthen Floors, Growing Your Own Culinary Mushrooms, Solar Ovens, and Fire-resistant Landscapes.

You teach a really diverse array of workshops. What do you enjoy about teaching people sustainable gardening and building techniques?

I want folks to know how to use nature, work with nature, and make their lives easier to live. Once you learn that, you automatically reduce the need to use pesticides, herbicides. fumigants – anything.  You, in essence, learn to observe and appreciate more.

Deb Tolman’s silo project, fronted by a lovely keyhole garden.

I saw on your website a picture of your “silo project.” It looks really cool. Tell me more about that.

Well, The Silo Project actually stands for Sustainable Information and Learning Opportunities, which encompasses everything I do, and then coincidentally I’m repurposing the silo in the picture to be a habitable space.  I intend to make it one block off the grid – attached to small kilowatt usage but not on community water.

Deb Tolman teaches Abundance NC’s DIY Sustainability Workshop: Keyhole Garden Build + Feast, this Saturday, September 20th, from 2-7pm, at The Plant in Pittsboro, NC.

At the workshop, you can learn how to make a keyhole garden, get a feel for how it works and how easy it makes gardening, gain a greater understanding of composting, and learn some tips for designing the garden.   After building the garden, participants will partake in a gourmet feast and enjoy drinks from Fair Game Beverage Company.

Go to the event page for the Keyhole Garden Build + Feast workshop to learn more and register online.  Pre-registration is required.