From Soil to Water and the Future of Sustainable Food

baby cucumbersOne of my first experiences on a farm opened my eyes to the fascinating interconnectedness of an agricultural system. For this reason, I find it truly rewarding to share in people’s excitement when they visit the aquaponics project. It was on that first farm visit that I realized agriculture meant more than growing a head of lettuce in a faraway field; it meant growing and nurturing a community of organisms, from the chickens that fertilize the soil to the microbes that break down their waste and the people that consume the food. Aquaponics takes these relationships out from hiding. Read More >

Why Tilapia? Species Selection at the Aquaponics Project

IMG_0853Tilapia is one of the most commonly raised fish species in aquaponics systems, but it is not universally desirable among consumers. Why is it that tilapia is such a common choice, and why are we raising them at the CLF Aquaponics Project?

  1. Tilapia are hardy. Really hardy. In the aquaculture industry they have a reputation for being very difficult to kill, especially compared to more finicky species such as trout. They can survive wider ranges in pH, temperature, and ammonia than many other fish species, and they quickly adapt to varying conditions. Read More >

Exploring the Food System with CTY

RS2878_Aquaponics_212-scrTwo weeks ago we hosted our second annual Food Systems and Public Health course in partnership with the Johns Hopkins Center for Talented Youth (CTY) at the Cylburn Arboretum. Six CLF staff members spent the day with 15 talented middle- and high-school students and their parents, and worked to define the food system, acknowledge harms, and develop a sense of hope for changing the world through the way we grow and eat our food. Read More >

Aquaponics is a “Growing” Field

Aquaponics survey respondents, 2014

Aquaponics survey respondents, 2014

Researchers at the Johns Hopkins Center for a Livable Future have conducted one of the first large-scale international surveys of aquaponics practitioners. For those who’ve noticed the buzz around aquaponics, the findings are not surprising. First of all, more than 800 people responded to the voluntary survey, which in itself demonstrates enthusiasm. Second, the results show that most respondents are new to the field, and third, that most of them are practicing as hobbyists. The survey has uncovered a couple of big themes in the field of aquaponics: enthusiasm and Read More >

Aquaponics: Lessons Learned on Water Quality

WaterEvery aquaponics practitioner shares the same fear: that one morning all the fish will be floating on the water’s surface. Although tilapia is one of the hardiest species raised in aquaculture, they still depend on well-managed water quality. Here are some lessons we have learned at the CLF Aquaponics Project.

Monitor Your Water Chemistry

Aquaponics is a living system that depends on a series of chemical and biological cycles and physical treatment of waste (i.e., filtration and sedimentation) to maintain healthy water. We regularly test for several parameters: pH (daily), ammonia, nitrite, nitrate, and alkalinity (weekly). With the help of bacteria, ammonia from the fish waste is converted into nitrite and then nitrate. Ammonia and nitrite are both highly toxic to fish, and we monitor these levels to ensure that they are Read More >

In Search of the Perfect Summer Crop

Romano pole beans reach for the ceiling at the CLF Aquaponics Project

Romano pole beans reach for the ceiling at the CLF Aquaponics Project

For many farmers, summer is the time of peak production and abundant harvests, but at the CLF Aquaponics Project our harvests peak mid-spring and start to decline as summer approaches. Farming is a learning process; and higher pest pressure coupled with hot temperatures in our hoophouse has made finding ideal summer crops a challenge.

Leafy greens and herbs are naturally some of the best crops for an aquaponics system, because they thrive in a nitrogen-rich environment. However, many of these greens prefer cooler weather, and as the temperatures in the greenhouse climb past 100 degrees Fahrenheit, even heat-tolerant chard gives up. We’ve found that many of summer’s star crops in the field, such as squash, tomatoes, beans and okra, simply do not produce well in our aquaponics system. The reason for this likely lies in the fact that these fruit-producing crops require high levels of potassium and phosphorous in comparison with leafy greens to encourage reproductive growth. Read More >

Redefining Waste in Aquaponics

cilantro-dill-gutterOn the surface, the aquaponics system appears to be a replica of a natural ecosystem where the word “waste” is an artificial concept. The fish don’t excrete waste, they excrete nutrients, and the plants take up these nutrients, filtering the water for the fish. However, in our earlier post “When the Fish and Plants Don’t Get Along,” we discussed how solid accumulation on the bottom of the plant beds can lead to poor water quality. To prevent this, we employ clarifiers after the fish tanks and before our plant beds; these tanks are designed to slow the water enough to allow solids to settle. Every day we drain the sediment from the bottom of the clarifiers to remove a total of 12 gallons of muddy, solid-filled water from the system. Just because we don’t want these solids sitting beneath our plant rafts, doesn’t mean they are a waste product. In fact, the solids are loaded with valuable Read More >

When the Fish and Plants Don’t Get Along

2013-aquaponics-tankIt’s easy to get excited about aquaponics. On the surface it seems simple: the waste from the fish is recycled into valuable nutrients for the plants, while the vegetables purify the water for the fish. Aquaponics, like any form of agriculture, is dynamic, changing with the seasons and over time. As the fish and plants grow, their needs change and shift the balance. Read More >

Raft to Plate: The Aquaponics Harvest

Harvesting-BeMore PhotographyHarvesting. It’s one of the most fun and rewarding tasks to do on the farm. Cutting a large bunch of celery three months after it was started from seed is satisfying. However, every hour spent harvesting is time we are not seeding, planting or farm planning, so the harvest must happen efficiently. Many farmers calculate the dollar amount they harvest per hour to assess their pace and the net value of certain crops. Plants must also be handled with care, not just to ensure the quality and safety of the product, but also to protect the remaining portion of the plant that will hopefully re-grow to yield multiple harvests.

At Cylburn, we harvest our vegetables every Friday for sale at the year-round Waverly Farmers Market on Saturday mornings. We sell through the Farm Alliance of Baltimore City, a network of urban farms in Baltimore that runs a collective market stand. Read More >

Aquaponics: It all Starts with Roots

celery-rootsWelcome to the Aquaponics Blog Series. We routinely share updates, photos and fun tidbits from the CLF Aquaponics Project. If you’re interested in urban agriculture, sustainable aquaculture, or hydroponics, be sure to check back regularly for new posts.

When young school groups come to visit the CLF Aquaponics Project, I love seeing the look on their faces when I pull a raft of celery out of the water, exposing the dense mass of roots underneath. Most of us gardeners never get to see the roots of our plants, but not only does observing the roots tell you about plant health, but it’s fascinating to see how every plant variety has slightly different root characteristics: did you know orange Swiss chard has orange roots? Read More >