Victoria County Master Gardener Association
ph: 361-935-1556
nancyk
2018 Aug 24
KEYHOLE GARDENING
Key to small gardens
August 24, 2018
By Bryan Serold - Victoria County Master Gardener
Edited by Charla Borchers Leon
Do you enjoy the taste of fresh vegetables but don’t have the time or physical ability to establish and maintain a traditional ground-level garden? Do you have limited space in your yard for a garden?
Are you looking for ways to recycle cardboard, newspaper, yard and kitchen wastes and other recyclable items?
If you answered yes to these questions, then a keyhole garden may be the key to providing a variety of homegrown vegetables year-round.
What is a keyhole garden?
A keyhole garden is a circular, raised-bed garden typically 6 feet in diameter ranging in height from 1-3 feet depending on what is a comfortable gardening level for you.
It includes an entryway in the shape of a keyhole or pie slice providing access to a composting basket in the center of the garden. The compost basket serves as the key source of nutrients and moisture for the garden.
The outer walls can be constructed from materials like brick, rock, cinder block, landscape timbers, wood shipping pallets and even old tires.
A keyhole garden can be filled with any kind of amended soil or compost or even a combination of carbon-containing materials like newspaper, phone books, cardboard or leaves as well as nitrogen-containing materials like fresh-cut grass, manure and kitchen wastes.
All of these materials used as fill for your garden are left to compost in place before planting.
Constructing a keyhole garden
- Select a site that will receive at least six hours of direct sunlight daily if possible.
- Measure and mark a 6-foot diameter circle on the ground.
- In the center of the circle, install a circular compost basket made of chicken or rabbit wire. The compost basket should be 12 to 18 inches in diameter and about 4 feet high.
- Mark a wedge on the ground from the compost basket to the outside wall of your garden. The wedge will serve as your access point to the compost basket and the center of your garden.
- Construct the perimeter walls up to 3 feet high using any materials available that will support the weight of wet soil.
- Line the bottom and interior walls of the garden with two to three layers of thick cardboard to suppress weed growth and improve soil and moisture retention. To line the inside walls, the cardboard should be dampened to make it easier to mold it against the walls.
PHOTO CONTRIBUTED BY PINTEREST.COM
Outer walls of keyhole gardens can be made of materials like rocks, bricks, wood shipping pallets, cinder blocks and/or landscape timbers as shown here. This raised bed garden is about 6 feet in diameter and about 3 feet tall. The entryway in the shape of a keyhole or pie slice provides access to the composting bin in the center of the garden. Recommended low-growing plants are seen in this keyhole garden with organic compostable food scraps (excluding dairy or meat products) in the center composting bin.
Filling your keyhole garden
Now that constructing the perimeter of your garden is done, the next step is to fill your garden with compostable materials that will provide a nutrient-rich growing medium for the vegetables you plant.
Fill with a commercially-made compost mix purchased in bags or bulk from local retailers – or save money by creating your own compost using a do-it-yourself layering technique with a variety of compostable materials.
- Use brown and green materials
One layering technique utilizes a variety of brown and green materials typically used when building a compost pile.
Brown materials include a mixture of dried shredded leaves, cardboard, newspaper, straw, twigs and other carbon-rich materials.
Green materials include a mixture of grass clippings, green leaves, coffee grounds, dry manure and other nitrogen-containing materials.
- 1/3, 1/3 and 1/3
- materials
A good rule of thumb when using this layering technique is to fill the bottom one-third of the garden with brown materials, another one-third layer of green materials followed by a final one-third layer containing a mixture of compost and potting/garden soil.
Be sure to water each layer with a water hose as you fill the garden to prevent materials from drying out.
Fill compost basket
Begin filling your composting basket with organic food scraps including things like banana peels, apple cores, raw vegetable scraps, coffee grounds and filters, tea bags, egg shells, grass clippings and any other material you would normally compost.
Avoid adding meat scraps and dairy product in the compost basket. Continue daily adding compostable materials to the compost basket if possible to provide a continuous supply of nutrients and moisture to the garden.
Refer to the sideline information for suggestions regarding recommended crops for keyhole gardens.
Water thoroughly at first; less in time
After planting has been completed, water thoroughly the entire area of the garden as well as the compost basket. Supplemental watering may be required until plants become established.
The garden should require less water once established. Moisture generated through the decomposition of organic material from the fill placed in the garden and compost basket should be sufficient to sustain your plants.
If plants show signs of distress due to lack of moisture, use a garden hose and water the compost basket only.
Enjoy the fruits (vegetables) of your labor.
The Gardeners’ Dirt is written by members of the Victoria County Master Gardener Association, an educational outreach of Texas A&M AgriLife Extension – Victoria County. Mail your questions in care of the Advocate, P.O. Box 1518, Victoria, TX 77901; or vcmga@vicad.com.
PHOTOS BY BRYAN SEROLD/VICTORIA COUNTY MASTER GARDENER
Several keyhole gardens were constructed last year by Victoria County adult and youth volunteers with guided assistance from Victoria County Master Gardeners for the Victoria County Community Gardens project adjacent to the Dr. Pattie Dodson Public Health Center in Victoria. At not quite knee height, the bottom of this raised keyhole garden was filled with several layers of cardboard to help keep weeds out. A 4-foot tall, 12- to 18-inch-diameter wire compost basket was centered in the bed and also supported by cardboard. The interior walls were next lined with dampened cardboard to help retain soil and moisture in the bed.
After lining the bottom and sides of this keyhole garden, it was filled with a mixture of compost and commercial bedding soil in preparation for planting. Alternative carbon-containing home products like newspapers, old phone books, cardboard and leaves as well as nitrogen-containing fresh cut grass, dried manure or kitchen wastes can be used. All of these alternative products are to be left to compost in place before planting.
After the growing medium was allowed to settle in the keyhole garden, low-growing vegetable plants are shown being planted by Victoria County youth and Master Gardener Mike Martignoni in the Community Gardens project. The center composting bin was filled with organic compostable food scraps to be continuously added as available for nutrients. The garden, including the compost bin, was thoroughly watered with supplemental watering if plants showed distress. Once established, decomposition of scrap materials and fill provided necessary moisture and nutrients for vegetables, which began to appear at normal growing intervals and were then harvested for consumption.
ph: 361-935-1556
nancyk