Beyond Playgrounds And Plants
Addressing barriers to food security
By T.O. Bowman
Photos: Oklahoma City Parks
Just five years after Oklahoma’s statehood in 1907, one of Oklahoma City’s oldest parks was purchased and became home to Will Rogers Gardens. The land, previously a dairy farm, began a transformation in 1932 when Henry Walters, the City Horticulturalist, designed the gardens’ ponds, plant beds, overlooks, and basic structures.
Featured amenities include the following:
The Charles E. Sparks Color Garden, a two-acre color garden nestled between the two ponds that bursts with seasonal blossoms.
The Ed Lycan Conservatory, a glass-enclosed Lord & Burnham greenhouse inspired by 19th-century Victorian architecture and named after the Oklahoma City Parks (OKC) first employee. The greenhouse was moved to the gardens in 1936 after it was constructed on the original state fair park in 1924.
The Margaret Annis Boys Arboretum, a rolling 10-acre area of the park featuring hundreds of varieties of trees, with a healthy mix of native species and rare specimens not often found in the state.
ADA-accessible trails and entry portals to accommodate a connection to nature for all visitors.
While many amenities are housed at the park and gardens, the land has taken on a new life in implementing the city’s first sustainability plan, adopted in the summer of 2020.
Food Security
Between 2010 and 2015, the number of census tracts defined by the U.S. Department of Agriculture as food deserts (both low-income and low-access) within the city increased from 27 to 31 percent. Oklahoma City, the largest urban center in the state, was identified by the CDC Behavioral Risk Factor Surveillance System in 2017 as having a higher percentage than the national average of adolescents/students in grades 9 through 12 who report consumption of both less than one fruit (51.9 percent) and less than one vegetable (46.2 percent) per day.
To help address at least one barrier to residents’ access to fresh fruits and vegetables and to reduce green waste sent to landfills from parks operations, OKC Parks implemented a pilot, circular, waste-disposal program and demonstration gardens at the historic Rogers Gardens.
The pilot program supports implementation of the city’s sustainability plan, adaptokc, and provides operational efficiencies, engaging learning experiences, and potential future revenue through sales of worm castings and finished compost. The project team diverts green waste from landfills and offers public-education opportunities to help visitors learn how to grow their own food through the employment of hungry worms, microorganisms, and hybrid sunfish.
Aquaponics
A favorite stop on tours of the Rogers Gardens, the aquaponics demonstration uses modern variations of some of the earliest/ancient aquaponics farming techniques to provide an educational experience. There are currently three techniques practiced in the demonstration:
Media-Based (MB)
Nutrient Film Technique (NFT)
Deep-Water Culture (DWC).
A fourth method—Towers—is planned.
Though different approaches are used, aquaponics basically involves using waste produced by farmed fish to provide beneficial bacteria and nutrients to plants that then purify the water.
The MB approach has the fewest components of the three and doesn’t require as much maintenance (i.e., filter replacements) because the growing media (fired clay) can break down larger bits of organic material. While the MB garden offers more stability for larger plants, it is usually viewed as a method for a backyard hobby and not scalable for commercial production.
In the NFT method, plants are placed in rock wool along narrow channels and are fed via a light, continuous flow, or film, of nutrient-rich water from the fish tanks. Only plants with small root systems can be grown in the NFT unit because the narrow channels are susceptible to clogging (even organic waste from the fish tanks can be enough to cause problems). Consistent piping maintenance helps combat clogging, and biofilters are used due to the lack of airflow.
The DWC unit—aka the raft method—is a relatively inexpensive, but most productive set-up of the three in use at the gardens. Fired clay helps stabilize the plants atop a deep-water tank that is separate from the fish tanks and allows more space between plants, which reduces stress and a potential for water-quality issues. Given the low-entry costs and high productivity, DWC units are a replicable, scalable solution that can help residents combat food insecurity.
The demonstration aquaponics gardens are so popular that OKC Parks has offered a class each spring to teach residents how to grow their own food using (or reusing) readily available materials from their homes or local hardware stores. Residents with limited growing space can produce a significant number of fruits, herbs, and vegetables using aquaponics. A 4-foot by 4-foot growing space can produce up to 200 pounds of food, or 7.65 pounds per square foot annually.
Composting
Parks departments across the country need a steady supply of nutrients to sustain the vast variety of beautiful, ecologically beneficial plantings for the public. To accomplish this, OKC Parks has increasingly looked to recycle valuable nutrients into the soil using naturally occurring processes and byproducts of routine maintenance rather than exclusively purchasing compost or using fertilizer products.
Prior to implementing a small-scale composting operation in 2017, green waste from the gardens routinely filled up trash bins destined for one of the high-volume landfills in the city. These landfills receive more than 500 tons of material per day and have resulted in recent re-zoning requests for additional tracts of land. The growth of landfills in the city not only consumes nearby land, but also contributes to increases in greenhouse-gas emissions. OKC Parks also sends about 750 pounds of paper from administrative offices to the compost operations annually.
Due to the relatively small size of the composting operation, some larger projects still require external purchases for compost. OKC Parks aspires to generate self-sufficient levels of compost for its operations and is eager to work with community partners that can provide local sources of compost feedstock, like coffee grounds, for the program. This expansion, however, will require at least one dedicated, full-time employee. While start-up costs were minimal for the pilot, expanding park operations to add a position on the heels of a COVID-19-related hiring freeze wasn’t feasible in the FY20 budget cycle, but may be a possibility when the state and local economic recovery accelerates.
Vermicompost
The smallest—but arguably the most critical—element of the closed-loop food production process is vermicompost, or accelerating decomposition of organic material with the help of worms! The worms, either Red Wrigglers or European Red Worms, are a renewable, high-protein resource for feeding the fish in the aquaponic tanks, as the worms multiply by 25 percent every three months—sometimes even faster in prime conditions.
The vermicompost/worm operation consists of two 32-cubic-foot boxes (4 feet by 8 feet by 1 foot) that basically function as a living machine. Worms’ digestive processes and the processed organic material (i.e., worm poop) create ideal conditions for beneficial microorganisms in the soil. More affectionately known as “worm castings,” the earthworm excrement serves as an organic fertilizer for plants.
The castings are effective at feeding plants without harsh chemicals, and since not every resident is ready to take on worm farming, just five pounds of worm castings cost about $15. At the time of writing, staff members have not yet harvested the worm castings, so metrics on yield or capacity are not available.
Conclusion
The department’s programmatic and operational changes emphasize resource conservation and contribute to a broader strategy of supporting residents in addressing barriers to food security. While the delivery of high-quality public services and grounds maintenance are routine undertakings for OKC Parks, incorporating sustainable best-management practices and rich, replicable learning experiences has a rippling impact on residents’ quality of life beyond just playgrounds and plants.
To learn more, visit okc.gov/parks.
T. O. Bowman is the City of Oklahoma City’s Sustainability Manager and directs the Planning Department’s Office of Sustainability. In this role, Bowman develops policy, promotes sustainability efforts, and manages grants, including energy-efficiency upgrades funded through the American Recovery and Reinvestment Act of 2009 and projects via the Federal Highway Authority, Department of Energy, and Environmental Protection Agency. Reach him at to.bowman@okc.gov.