OBSERVATIONS ON A KEYHOLE GARDEN
A couple of years ago I saw an Oklahoma Gardener Magazine article about keyhole gardens. Always looking for new ideas and philosophies, this intrigued me. Further research by friends found photos of active keyhole gardens and a documentary video of a charity group teaching villagers to use this growing technique in their homes.
What is a keyhole garden? Google this and you will see many fancy formal gardens using manufactured stone and ornamental plants. Dig deeper and you will find the uses that fascinated me. Most suitable in high altitude arid regions of Africa, these structures allow a family to grow sustainable crops near their huts using green techniques and gray water from their home to provide food during the 3 month dry season.
Plans for my garden started over 18 months ago, cutting down a dying pecan tree and laying out the footprint for the stone structure. These gardens are, by necessity, no bigger that 10 to 12 feet in diameter, keeping the entire growing area within reach from the outer wall. A more or less round stone-walled garden is created with a notch, or keyhole in the wall extending to a “chimney” of sticks and reeds 2 feet in diameter and taller than the tallest part of the garden. In my structure I used rebar and plastic fencing with 3/8 inch square openings. The wall is made of castlewall stones and double-sided matching stones for the keyhole to allow vertical faces on the keyhole.
Some decisions may not have been the best design techniques for this particular garden. I offset the chimney to miss the flush-cut tree stump. I also planned the lines of the wall to follow curves of my brick pathways. This resulted in a deeper reach required to work some areas of the garden and a possible uneven distribution of water dispersal throughout the entire planting area. To verify possible shortfalls in this area I have begun testing moisture levels before watering and after watering for specific time and flow rate. My Wal Mart moisture sensor is a 10 inch probe with a meter movement from 1 to 10, wet to dry. A few measurements may give me an idea if I need to compensate my watering patterns in the wider sections of the garden.
By my best observation, the chimney should have several inches more material than the outer circle. The outer circle should have its material sloped up toward the chimney. I am questioning whether the compost should be fully composted material or can be mixed with fresher vegetable scraps. With each watering, the compost level does settle by several inches and has a tendency to tunnel the water to one side without frequent stirring and leveling of the surface between waterings. I am currently adding a kitchen bucket of scraps, egg shells coffee along with filters and bags, fresh vegetable peelings and pieces and egg shells about each third topping of the chimney.
For the first trial of my garden I planted squash, zucchini, tomatoes, 2 varieties of peppers, and sweet potato vines for table consumption. The squash varieties are spaced around the inner ring of the garden, with the tomatoes planted in a grid on the widest slope of the garden. Sweet potato vines are randomly space counter-clockwise from the keyhole, reaching around 2/3 of the circumference. I covered all bare areas of the planting bed with 10 inch sections of cane growing along my back fence, consisting of stalk sections and green and dry leaf segments. My plan is to train the sweet potato vines to grow counter-clockwise, looping back when the side of the keyhole is reached. To assure good production I will have to remove the green cover in areas where the vines appear to be setting roots for each potato. The tomatoes will receive cages to control their growth, with the peppers getting either cages or stakes to support heavy branches.
After the first week or two of observation I noted a great amount of settling in some areas of the bed. This could lead to excess water traveling to these areas and will have to be reshaped with additional dirt as the weeks go by. I feel this is a one-time problem that can dealt with in the beginning growing season.
The examples of African keyhole gardens in use show concentrated plantings of greens crops, cabbage, lettuce and such leafy crops. To match my functional and ornamental designs, my crops are not quite as densely planted but will produce crops that we will consume.
Other considerations when finishing off a keyhole garden are wall height (additional dirt height above a comfortable reaching distance adds no benefit), and ornamentation. The wall itself can be topped with attractive planter pots of garden art. An interesting use may be to purchase (locally available) matching wall block which incorporate a planting pocket within each block, providing decoration with draping vines or crops. These can be set in two or three block segments of the wall to not interfere with easy flow around the garden area.
After 18 months of volunteer labor and a lot of planning small details, this may be my most cherished addition to my yard. Get in touch with me for future updates and lessons learned as the growing year progresses. Freddy Hill firstname.lastname@example.org.