Keyhole Gardens: A Drought Tolerant Composting Garden

By Bev Walker
April 3, 2016

A Keyhole Garden is a raised bed, lasagna garden, composting, and recycling system all rolled into one. The design creates a garden that uses recycled materials, less water and maintenance, and can be made handicap-accessible!

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

Keyhole Garden plan viewThe 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

Keyhole Garden Cross-section A-AThis 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.

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



  About Bev Walker  
Bev WalkerI was a serious organic gardener and composter 30 years ago, then my life took me in a new direction with kids and career. I am just now returning to gardening and learning new techniques, and loving every minute of it. I hope to share my experiences with you from my shady yard.

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