How to build a keyhole garden

Garden-planting season is upon us and Canada’s home improvement stores are selling ready-to-assemble “keyhole gardens.” Have you seen them?

This style of compost-fed, raised-bed gardening is becoming more popular in North America, but the concept originated in the 1990s in southern Africa, where scarce water and infertile land was causing a food crisis. The keyhole garden design was developed by C-SAFE (the Consortium for Southern Africa Food Security Emergency), and was especially helpful for people suffering from HIV and AIDS.

Miriam Chang is World Vision Canada’s Health and Nutrition Sector Lead. She remembers first encountering keyhole gardens in Lesotho.

“These are designed to reduce labour because this approach allows people to grow crops densely in a small space,” she explains. “There's less bending when working with a raised bed, which is a consideration for communities with a high burden of HIV/AIDS, or people living with chronic illness who find the more traditional ways of growing food crops in-ground too physically demanding.”

The simple gardening approach quickly spread to other households—not only those struggling with illness—because it is efficient, sustainable and low cost.

Using kitchen gardens to combat malnutrition

Keyhole gardens are one of several methods World Vision uses when working with families to start backyard gardens, also known as “kitchen gardens.”

Cultivating vegetables close to the home provides a handy source of nutritious food that can be incorporated into meals, increasing the family’s health and nutrition. Compact, vertical solutions are especially helpful where growing space is limited.

“There are all manner of small-scale vegetable gardening methods that people use, ranging from sacks and tires to other containers,” explains David Mbugua, Grant Manager of World Vision’s RESILIENT-WE project. “The key in all of them is to ensure use of good quality soils mixed with manure or compost, while maintaining good aeration and drainage.”

Basics and benefits of the keyhole garden

A keyhole garden is a raised-bed structure built around a central composting basket. When the compost basket is watered, nutrients flow into the garden bed and fertilize the soil.

The garden gets its name from its shape, which is traditionally a circle with a triangular notch on one side. This notched entrance allows the gardener to access the plants and compost basket with ease. When viewed from above, it resembles a keyhole.

This sustainable approach to gardening:

• Enriches the soil through natural composting without expensive chemical fertilizers.
• Is low-cost, built using simple materials like rocks and tin cans.
• Conserves water, since household greywater can be used to water the compost basket.
• Is accessible for people with health and mobility challenges thanks to its raised bed construction.

Since the structure is good at retaining water, it’s a great approach for dry climates or places where collecting water is difficult. On the flip side, as a mom named Asma experienced in Bangladesh, keyhole gardens can also help when there’s too much water.

A solution for Asma’s flooding problem

Asma’s garden plot, cultivated on a riverside in Islampur, Bangladesh, was continually being wiped out by flash floods. It was difficult for the mom of three to get the nutrition she and her children needed—especially when she was pregnant.

Through a World Vision project, Asma learned to build a keyhole garden and found that the structure was resilient even during floods. She was able to grow a variety of vegetables including Indian spinach, red amaranth, radishes and eggplant. Eager to share what she’d learned with her neighbours, Asma became a demonstration farmer.

“These initiatives of the project are very essential to change the lifestyle of a family, as well as society,” she says.

Between the homegrown veggies and other health and nutrition training, Asma has noticed that her family’s medical bills have gone down.

Learn to build your own keyhole garden

While prefabricated options are available in Canada, the beauty of the keyhole garden is in its flexible, low-cost design.

In addition to the video above, here are some tips for getting started.

• Think of the vegetable varieties your family and community will actually enjoy eating, and start with those.
• Plant a least four types to keep your garden fertile and resilient to pests.
• We suggest root veggies like carrots, onions, beets, garlic and radishes interspersed with leafy crops like spinach, Swiss chard, lettuces and herbs.
• Avoid plants with larger root systems and those that take up a lot of space, like tomatoes, peppers and squash.
• Join a local gardening group to learn and share experiences with others.

Finally, as your garden succeeds, consider sharing your extra produce with your neighbours or local food bank. Because yes, gardens grow food—but they can grow community as well.

Written by Katie Hackett with notes from Miriam Chang