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Community Partner:
Middlebrook Gardens, supervised by founder Alrie Middlebrook, specializes in native garden landscapes that “reflect the natural beauty of California, conserve precious natural resources and link the urban landscape closer to nature” (Middlebrook Gardens, n.d.). Founded in 1976, Middlebrook Gardens is located in San Jose, California. At its heart, it is a landscape company focused on design and maintenance, with emphasis in ecology-based landscaping, native plants, environmentally friendly products and water conservation. Middlebrook Gardens seeks to address the topic of environmental degradation through regenerative and organic farming, youth-led events, and a number of environmentally sustainable projects. These projects include, but are not limited to, aquaponics systems, gray-water systems, composting systems, and stormwater capture systems. Middlebrook Gardens has received numerous awards including the prestigious Acterra Business Environmental Award, in the Open Space and Habitat Preservation/Restoration category, as well as a 2012 Best San Jose Award in the Landscape Services category given out by the USCA (Middlebrook Gardens, n.d.).
Aquaponics Systems:
Aquaponics is a gardening practice that pairs fish and vegetable growth into a single, self-contained and self-sustaining system. In this integrated process, fish waste is converted into nitrates by microbes and then in turn used as a food source for plants, which go on to filter water for fish reuse. There are three primary reasons as to why people choose aquaponics systems over traditional gardening practices. Aquaponics uses only one-tenth of the water that traditional soil-based gardening uses. Additionally, aquaponics systems are free of pesticides and toxic run-off. They also require very little maintenance and can be scaled for practically any space.
There are several growing techniques that can be used in aquaponics systems. Middlebrook Gardens currently uses both raft-based and media-based aquaponics. The current system in place at Middlebrook Gardens, however, is not properly functioning. The water flow rate coming out of the PVC pipes is not optimal in part due to algae growth within the pipes. As outlined above, it is our overarching goal to implement a functioning aquaponics system at Middlebrook Gardens.
Project Goals:
The California Native Garden Foundation (CNGF) is in need of a functional aquaponics system so that Middlebrook Gardens may be used as an educational space for students this coming summer season to teach awareness of a more just and sustainable world. The project objectives are as follows:
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Design a functioning aquaponics system that: a) successfully grows a variety of plants, b) has enough water flow to minimize algae growth, and c) supports plants that intake enough fertilizer to minimize algae growth
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Create a sustainable aquaponics system that lasts as long as possible with deteriorating and negatively impacting both the plants and the fish
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Implement a system with an educational aspect in mind both a) incorporating signs to differentiate the purpose of each system part, and b) implementing simplicity so that every major design aspect is visible
Water Management and Food Safety in Aquaponics Systems:
In a review of 122 papers from the Italian Department of Agronomy, it was found that the optimal flow rate for aquaponics systems is between 0.8 L/sec and 8 L/sec, depending largely on the food grown in the system. It was also found that intermittent flow is more effective at oxygenating the water and distributing nutrient-rich effluent throughout aquaponics systems. Additionally, both medium-based and floating-raft methods are more effective than nutrient film technique (Maucieri, 2018).
Hydroponics is acclaimed for its environmental efficiency. However, few microbial studies have been done on food safety. Since the system recreates natural aquatic filtration, many trust the safety of food grown in hydroponics. Regardless, food safety practices remain an important part of hydroponics. Harvesting without touching floats or roots is important in the prevention of contaminating produce with effluent. Educating members of the garden will be an important aspect of maintaining a healthy aquaponics system.
Hollyer, Jim et al. “On-Farm Food Safety: Aquaponics.” College of Tropical Agriculture and
Human Resources at University of Hawai’i at Mānoa: Food Safety and Technology, FST-38 (2009). Accessed April 20, 2019, from https://www.ctahr.hawaii.edu/oc/freepubs/pdf/fst-38.pdf.
Maucieri, Carmelo et al. “Hydroponics systems and water management in aquaponics: A
review.” Italian Journal of Agronomy, volume 13:1012 (2018): doi:10.4081/ija.2017.1012. Accessed April 20, 2019, from https://digitalcollection.zhaw.ch/bitstream/11475/5952/2/1012-Article%20Text-7786-4-10-20180313.pdf.
Middlebrook Gardens. (n.d.). Accessed April 02, 2019, from http://middlebrook-gardens.com/.
“What is Aquaponics?” (n.d.). Accessed April 20, 2019, from