Aug. 9, 2012 - Last year, during the worst single-year drought and heat wave in Texas history, several gardens in Bosque County flourished. The gardens were small, about six feet in diameter, but wildly productive. They were keyhole gardens and they were introduced to the county by Dr. Deb Tolman.
The idea of keyhole gardens didn't originate with Tolman, but she brought it with her to Bosque County. That her own gardens and the others that she has helped start more than held their own last summer has other communities and gardeners in Texas, and beyond, taking at least a peep at keyhole gardens.
Keyhole gardens are generally six feet in diameter and waist high with a center basket of wire mesh one-foot higher than the rest of the garden. They are enclosed within a three-foot high wall of rock, metal wood or even cinderblocks. The walls are lined with cardboard and the garden area is filled with wet, compostable material. A slice of the wall is cut out to allow access to the garden and the basket. From above, it looks like a keyhole.
The soil is built from scratch using a host of compostable materials -- especially cardboard, lots of cardboard. Built properly, a keyhole garden creates its own fertilizer and, to a large extent, its own moisture; even the hardiest garden needed some water last summer.
"It needs some water to get it started. You mulch it and water it in to get it started, but it's designed not to need a lot of water. It's a way to garden in Texas during a drought," Tolman told a group of Master Gardeners in Bell County recently. "You can also put a 55-gallon drum on a drip system if you want."
The center basket is filled with phone books, newspapers, kitchen scraps and more cardboard. The kitchen scraps (but not meat scraps) are important because they are about 95 percent water and provide several key nutrients as well as moisture. The material is segregated into greens and browns. Green materials like the grass clippings provide nitrogen. The browns, including all that cardboard, add carbon. Tolman recommends a ratio of three browns to one green to keep the mixture from getting too hot.
If everything is done right and everything goes right, all of the original materials -- all that cardboard and all those newspapers and phone books and kitchen scraps -- will have turned into soil and the keyhole garden will be up and running itself in about four weeks. Insects do most of the heavy lifting in this type of garden.
"It operates by critters," Tolman said. "You have to have the little critters. It's at the heart of the science behind this."
The ideas behind keyhole gardening originated in Africa where missionaries found a way to grow food without soil and without very much water.
"Three keyhole gardens can feed an African family of 10, year-round," Tolman said.
Keyhole gardening is a minimalist technique, but Tolman thick-plants the gardens; in one garden she had 70 tomato plants, which provided not only tomatoes, but also shade for the soil. Heirlooms are particularly adapted to this style of gardening because they reproduce each year.
"You get the same thing, year after year," she said.
The first demonstration keyhole garden that Tolman built and grew in Bosque County was at a hardware store in Clifton. Just before the garden was ready to be unveiled to the public the county was hit with a sudden 10-inch rain that washed away part of the wall enclosing the garden.
"That turned out to be a good thing," she said. "With the garden exposed like that you could see the roots coming straight down like they're supposed to. You could see it working."
Even though her own gardens provide her with nearly all of her food year-round, she doesn't garden in the summer anymore -- not in Texas.
"It just doesn't make sense," she said. "I grow heavily on either end, but in the summer I start doing prep work for the fall garden, getting newspapers and cardboard and planning what to plant and where to put the garden."
Tolman brings a lot of academic and real world experience to the place. She did graduate work at North Carolina State, Virginia Tech University and Texas A&M and has a PhD in Environmental Sciences/Resources and Geography from Portland State University. She lives in a converted oat bin on Jim and Mary Lou Starnater's StarHaven Ranch where she runs her own company, Avant Gardens, and offers consulting, landscape design and implementation to her clients. She also provides a lot of information for free as an educational service to civic, gardening and other groups.
When she isn't working in her own gardens, helping other people with theirs or making presentations, Tolman also researches and advises on other matters of sustainable living like rainwater harvesting, cheesemaking, holistic range management, aquaponics, solar energy and fire-resistant landscapes.
"Keyhole gardening is about 1/20th of what I do," she said. "It's part of a much larger focus."
For more information, including step-by-step instructions on keyhole gardens, go to her website at debtolman.com.