What Exactly Is A Keyhole Garden Anyway?

By Charlie O'Halloran and Tara Roberts, CCMGA Master Gardeners

Named for their unique shape, keyhole gardens originated in the country of Lesotho in South Africa in the 1990s, where the arid climate, extreme drought conditions and poor soil conditions made gardening a challenge. Natural stones readily available from the land were ideal for the keyhole design, which is typically a 2-3 feet high, above-ground, semi-circular garden with a keyhole-shaped opening on one side. Keyhole gardens are approximately 6 feet in diameter.

The keyhole indentation allows easy access to a compost collection basket in the center of the circle. The keyhole garden incorporates compost directly into the garden rather than having a separate compost pile where you must wait for materials to break down prior to adding usable compost into your garden beds. Just like with traditional composting, gardeners add a combination of compostable materials such as cardboard, newspaper, grass clippings, coffee grounds and other kitchen scraps directly into the compost collection basket within the keyhole garden. This design saves water because it retains moisture, is more space efficient, and creates its own nutrient-rich soil for growing while also reducing household waste thanks to the built-in compost component.

Keyhole gardens are now found worldwide and are ideally located near the kitchen for easy access. The keyhole design and height provide easy access since the keyhole allows gardeners to collect their harvest without reaching too far across or bending over. Keyhole gardens are a wonderful option for gardeners with physical limitations.

Keyhole gardens are ideal for intensive planting, a technique where plants are planted close together for an increased harvest. Herbs and leafy green vegetables such as lettuce, kale and spinach are good choices for keyhole gardens. Root vegetables such as onions, garlic, carrots and beets also do very well. Almost any vegetable can be grown in a keyhole garden, but consider the height and sprawl of a plant and the size and height of your bed before deciding to incorporate certain plants. Tomatoes tend to grow tall, so your harvest might be out of easy reach if your keyhole garden is 2-3 feet above ground level. Plants that grow wide are often not ideal. Think about the room required for a squash plant. Choosing these plants could limit the space in your garden, but ultimately, you should choose vegetables you and your family enjoy eating.

Collin County Master Gardeners have taken these basic concepts and created several modified keyhole gardens at Myers Park in northern McKinney. These beds are located near the newly revamped CCMGA greenhouse and are being used as teaching gardens for youth education programs. While these beds do not follow the traditional keyhole design of raised stone beds, they were built incorporating certain keyhole design elements with various styles of compost bins placed inside the beds. Master Gardeners Lionel Primeaux and Beth DiGioia were instrumental in constructing these modified keyhole beds using available materials, allowing different composting methods to be demonstrated, including a compost cube with bottom access, a tumbling barrel and a single barrel. All of these composting methods demonstrate the benefits of using compost tea on plants since water added for the compost process becomes a compost tea as it leaches into the bed and increases plant production. CCMGA volunteers will document results based on the Texas A&M AgriLife research protocol.

These modified keyhole beds are part of the CCMGA Environmental Study Greenhouse Center, which offers educational tours for students from elementary through high school ages, including the homeschool community, which has become increasingly active in CCMGA educational tours, demonstrations, activities and group discussions. The learning center offers educational programs for hobby greenhouse, trees, entomology, composting, rainwater collection, propagation, seed starting, as well as growing vegetables, perennials and annuals at our national and international award-winning research gardens at Myers Park.

If you're interested in CCMGA Environmental Studies programs for students, please contact https://ccmgatx.org/forms/ContactUsForm.aspx and select "other".

Additional resources for keyhole gardens can be found by visiting the following Texas A&M Extension links:

https://txmg.org/bluebonnet/twenty-years-and-counting-the-keyhold-garden/
https://youtu.be/52AqHjG35vw?si=kQjucdjd9FxLQxJq
https://travis-tx.tamu.edu/files/2021/09/How-to-build-your-keyhole-garden-EAGF.pdf