Wednesday, December 2, 2015

My Keyhole Garden


Now that the harvest is over and Thanksgiving has come and gone, I want to report on the results of my “keyhole” garden experiment.  The idea for this project came from the book, Gaia’s Garden: A Guide to Home-Scale Permaculture by Toby Hemenway.  We’re interested in applying permaculture concepts to our land and gardens and we’ve already started to implement some of the practices over the past year, such as chop-and-drop mulching, rainwater conservation, and beginning to plan for layers, guilds, and zones.  It will be a multi-year process, like all gardening endeavors!  This Spring, I had a brand new garden bed and I was excited to try out the concept of a keyhole garden.

What’s a Keyhole Garden?

Image credit:
http://southwoodsforestgardens.blogspot.com/
Keyhole gardens are raised bed gardens laid out in a shape reminiscent of a keyhole—a semi-circle or horse shoe shaped bed with a deep notch or central path extending into the garden’s center.  The design allows gardeners to grow more in a smaller space and to irrigate more efficiently.

Often in a conventional garden, plants are in rows, alternating with walking paths; with a keyhole design, gardeners can access plants from the central notch or path and also from the outside of the garden bed.  Fewer paths also means more growing area and soil that is less compacted, which is particularly important in permaculture because it emphasizes a no-dig method of gardening.

A keyhole garden may be watered with just one sprinkler placed in the center of the bed.  The shape of a keyhole garden can also be used to “catch” sun.  With the path or notch oriented toward the South, the “U” shape of the bed captures and holds sunlight.  This effect can be enhanced by planting taller vegetables in the back of the bed, trapping light and sun in the garden and also providing a windbreak.

My Own Keyhole Garden Design

Although my new garden bed is square, it was the right size for making use of the keyhole principal.  In keeping with the no-dig method, we prepared the bed a few weeks in advance by laying cardboard sheets over the soil to block sunlight, killing the grass and weeds. Tarps went on top of the cardboard, held down with rocks. Early in May, we removed the tarps and broke up the cardboard into smaller pieces for composting in the soil.  My brother-in-law provided us with a truckload of excellent composted manure so which gave us a few inches rich, moist soil from the start. 


My keyhole garden in the morning sun.  

First, I did a sketch of the garden and then we laid out the central path with large flat stones. I chose to make the garden entrance where it provided easiest access but also in accord with access to sunlight on our property.  Our path begins at the Eastern corner of the bed and extend diagonally to the center.  This alignment worked best for us in terms of access from the house, and also because we have tall trees that block much of the sun to the South.  Morning sunlight is drawn down the path toward the western edge and held there through mid-afternoon when the sun slips behind the trees.

Side view of the garden in July
I wanted this bed to be a kitchen garden—an informal mixture of small veggies, herbs, and annual flowers.  I lined both sides of the central path with my favorite cooking herbs.  Lettuce and cilantro grew at the top of path and in a spot where I could plant a second crop in mid-summer.  Behind the culinary herbs, I placed medicinal herbs like borage, calendula, and lemon balm. Plants that climb and sprawl went in the corners (Golden Sun cherry tomato, cucumbers, and Delicata squash) where they would be free to spill over the edges of the garden.  I also found a spot for alpine strawberries along one edge. Finally, I interwove some of my favorite flowers—sweetpeas, cosmos, dahlias, and zinnias. 

I found that the keyhole design, allowing me access plants from outside and from the center, made it easier for me to stay on top of dead-heading, harvesting and pest patrol.  Almost everything I planted was a success (except for a wormy cabbage that had to be pulled) but it also brought me so much joy.  I harvested many wonderful salads and used herbs in new ways, both culinary and medicinal.  I’ve never grown calendula before but I fell in love with that plant.  I put calendula flowers in my salads and harvested some to dry, but most of all, I simply enjoyed looking at its cheery golden glow in the garden every single day. 

Keyhole Gardens in Arid Regions

My delicata squash plants, beginning to spill over the edge.
It’s rather interesting to know that keyhole beds were originally designed by charitable organizations as a means of allowing people in arid or drought-stricken regions the means to raise food for their families; a number of organizations are promoting and implementing keyhole gardens in Africa.  Since creating my own bed, I’ve learned that the center of a keyhole bed sometimes contains a compost bin constructed out of chicken wire.  Nutrients from the central compost bin slowly leach into the garden, steadily improving soil.   Rain water and gray water added to the compost also helps irritate the garden.  It’s a great idea but it wasn’t mentioned in Gaia’s Garden so I didn’t implement it in my initial design.  It’s something I would like to experiment with in the future, although it seems to be favored mostly by gardeners in climates with longer, hotter growing seasons.  Living in a cold climate, I am concerned about whether my compost would decompose quickly or thoroughly enough.  It could be pretty unpleasant if the compost was unsuccessful, so I will need to think more about this before implementing.  However, keyhole gardening could be an excellent choice for areas that are struggling with drought conditions.  This site has some excellent photos and diagrams of keyhole gardens in Africa and North America:  http://www.inspirationgreen.com/keyhole-gardens.html