Consider A New Experience with an Old Technique--Keyhole Gardening

Unique Keyhole Gardening Explained

Allan Robinson: Ask A Master Gardener

Tuesday, July 11, 2017

Q: Over the years, I have heard the term “keyhole gardening” from time to time but don’t know anything about it. Is it better than regular gardening? Tom A., Jenks

A: As Oklahoma summers continue to get hotter and drier, gardeners are looking for ways to prolong the growing season while responsibly maintaining natural resources. Keyhole gardens may just be the answer by providing several advantages to conventional gardening, such as simple construction, soil enrichment, moisture retention, labor savings and extended vegetable production.

Originally developed for use by the chronically ill in third-world countries, keyhole gardens have proven to be an effective way to grow vegetables year round in moderate climates, semi-arid environments and locations with poor soil because they are constructed in such a way as to warm, nourish and retain moisture in the soil.

This type of garden has helped many populations vulnerable to hunger and food insecurity improve resiliency to shocks such as drought. Because Oklahoma has experienced semi-arid environmental conditions in recent years, coupled with the fact that our horticultural population is living longer and wanting to garden longer, keyhole gardens may very well have a natural place in our area as well.

The name comes from its original design as a relatively small round garden with a low outer wall and a space in the middle to allow a person (especially those who are physically weak or have a disability) to work the garden with minimal effort. The raised bed is surrounded by stones or equivalent material, literally of any type. Inside, the walls are built-up of layers of rapidly decomposing organic material that serve the dual purpose of continually adding nutrients to the soil and retaining moisture, making it much more productive than a conventional garden, even in cold and dry winter months.

Once built, the garden requires little ongoing maintenance; it does most of the work. Also, few additional inputs, such as fertilizer, are required.

Construction of a keyhole garden is rather simple and fun and promotes the use of inexpensive and locally available resources. You can even get your kids involved.

The outer wall can be constructed of anything resilient (brick, stone, wood, hard plastic, old tires, etc.). Internal materials include rocks and a combination of organic materials, such as small tree branches, loose twigs, wood chips, cardboard, newspaper, grass clippings, green or brown leaves, manure, compost and soil. The typical garden is only 6-7 feet in diameter.

Garden tips

·        For all your plants, ornamental or vegetable, mulching and correct watering are keys to surviving the heat of the summer. Mulch conserves water and reduces ground temperature.

·        Fescue lawns need 2 inches of water per week to survive summer; Bermuda grass needs about half that amount. Watering less frequently and more deeply is better than daily shallow watering.

·        Brown patch disease of fescue lawns is appearing now, related to excessive rains, heat and high humidity. Wet grass leaves promote the disease. Therefore, if you water in the mornings, allowing the leaves to dry during the day, there will be less likelihood of infections. Fungicides are available, but OSU feels the fungicides available to homeowners are not nearly as effective as those available to professional licensed applicators. None of these chemicals will cure existing infections; they only prevent new disease at best.