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Center for a Livable Future


Food System Lab @ Cylburn


Welcome to the Food System Lab at Cylburn. Scroll through to take  a virtual tour  of our farm.
Welcome to the Food System Lab at Cylburn. Scroll through to take a virtual tour of our farm.
We practice a system of agriculture called aquaponics, in which we raise fish and plants together. The fish waste provides nutrients for plants to grow and hydroponic plant beds filter the water for the fish. Water continually recirculates between the fis
We practice a system of agriculture called aquaponics, in which we raise fish and plants together. The fish waste provides nutrients for plants to grow and hydroponic plant beds filter the water for the fish. Water continually recirculates between the fish tanks and the plant beds, creating a water efficient and low-waste method of agriculture. Photo: Florence Ma
Each of our 200 gallon fish tanks is home to at least 20 tilapia. Fresh water from plant beds is pumped into the fish tanks and air bubbles are added to provide oxygen so fish can breathe. Electric heaters keep water warm in the winter. Fish waste and water flow through drains at the bottom and into the clarifier tanks. Photo: Florence Ma
While many freshwater fish can be raised in aquaponics systems, tilapia are one of the most hardy and common. They are omnivorous, meaning they survive on plant protein, making them more sustainable to feed than carnivorous farmed fish. Photo: Florence Ma
Clarifier tanks: Water drains from the fish tanks into the clarifier tanks. These tanks allow solid fish waste to settle to the bottom, where we can remove it and use it as fertilizer for plants grown in gravel containers or soil beds.
Mineralization tanks: These tanks play a crucial role in water filtration by providing a home for beneficial bacteria on cylindrical plastic pieces called biomedia or on coils of plastic netting. The bacteria convert molecules of ammonia, excreted by the fish, into nitrite and then nitrate. Ammonia is a form of nitrogen toxic to fish, and nitrate is a valuable nutrient for the plants. Photo: Florence Ma
Plant Beds: These shallow, rectangular tanks are the hydroponic component of the system where a diverse array of vegetable plants are grown in nutrient-rich water circulating throughout the system. Plants sit in floating foam boards with roots in the water. They scrub the water of nitrate and other nutrients before it returns to fish tanks.
We start all our seeds in trays filled with coconut coir, the husk from a coconut. The seedlings are grown until they are large enough to be transplanted into the hydroponics rafts. Photo: Florence Ma
We harvest vegetables every week in the summer and every other week in the winter. After harvest, unusable plant material (e.g., roots, stems, leaves) is fed to the thousands of worms living in the worm-composting bin. Worms turn this organic material into rich soil that accumulates at the bottom of the bin. That soil can then be used in our soil bed, and worms can occasionally be harvested and fed to the fish. Photo: Florence Ma
We can grow certain types of plants in the soil bed that do not grow well in the aquaponics system, such as root crops like potatoes or carrots. We fertilize our soil bed with effluent from the aquaponics clarifier tanks and worm compost generated in our worm bin. Photo: Florence Ma

The Food System Lab @ Cylburn is an urban teaching farm in Baltimore City, operated on the grounds of the Cylburn Arboretum by the Johns Hopkins Center for a Livable Future (CLF).  Our diverse educational programs emphasize the important connections among the living components of a small-scale agro-ecosystem and offer a compelling introduction to an equitable, healthy and sustainable food system. Visitors engage directly with a variety of food production practices, including aquaponics, a system of agriculture that combines fish farming with hydroponic plant farming.

Visit Us: The Food System Lab is free and open to individual drop-in visitors for information and tours during the following times: 

  • Wednesday, 10am – noon (We will be closed on Wed, August 24 and November 23)

  • Sunday, 1pm – 3pm

Groups of five or more are by appointment only (see below).

School and Group Programs

Group Tour /Program Inquiry Form

We offer tours and longer theme-based programs targeting middle- and high-school students, college students, and adults. Our hoophouse can accommodate groups of up to 25. The Farm Educator will work with you prior to your visit to tailor the program according to your group’s size, schedule, and learning objectives.

  • Tours: Our 45-minute tour explores the operation of our urban farm and the relationship between the fish, plants, microorganisms, worms, soil and water. We also offer an abbreviated 20-minute version.
  • Theme-based Programs: These 90-minute programs examine our urban farm in the context of the broader food system. Students engage in activities designed to raise awareness about the complexities of our food system and encourage a deeper level of thinking about our relationship with food. We currently offer the following themes:
  • Aquaponics and Aquaculture: Fish, Farms, Food: As ocean fish harvests plateau and the population grows, the aquaculture (fish farming) industry continues to expand. We’ll discuss aquaculture and take a look at how aquaponics can offer a sustainable alternative. How does the aquaponics system work? How does it differ from other methods of aquaculture? What are some advantages and disadvantages of aquaponics?
  • Baltimore’s Food Community: Come explore Baltimore’s unique food environment with a visit to our active urban farm. We’ll dive into the Baltimore Food System with maps and activities; and discuss the potential of urban agriculture in our region to improve food systems and address hunger. Ideas welcome!
  • Water Quality and Agriculture: Agriculture is the single largest user of freshwater resources on the planet, accounting for 70% of freshwater use by humans, and agricultural practices can have a large impact on environmental water quality through discharge of pollutants and sediments into local waterways.  Aquaponics, as a closed loop water system, can teach us about how to balance agricultural production with water quality. In this activity, we will discuss the water quality parameters for aquaponics systems, including pH, ammonia, nitrite, nitrate, and Total Dissolved Solids. We will then take water samples from the system and perform water quality tests for each of these parameters. Lastly, we will analyze the results to determine their significance for the health of the system.

There is no charge for groups of fewer than 25 for the standard tours or 90-minute programs. Please inquire with the Farm Educator about larger groups and expanded programming options.

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For more information, please contact:

Jesse Blom
Food System Lab Manager and Educator

Additional Resources

CLF’s Aquaponics Research: