Aquaponic systems allow crop and fish production year-round

PETERSBURG—An aquaponic system combines traditional aquaculture with hydroponics in a symbiotic environment to grow crops, often greens or lettuce.

The systems can be in a small greenhouse, sunroom or room with grow lights, explained Virginia Cooperative Extension fruit and vegetable specialist Chris Mullins at Virginia State University. Mullins appears on Real Virginia, Virginia Farm Bureau’s weekly television program.

“The fish provide fertilizer and water for the plants, plus the fish have a nice, warm place to grow,” Mullins said. “These systems are becoming more common in the United States and even right here in Virginia. They’re great for home or hobby gardeners.”

Lettuce that is sold in “clamshell” packaging at the grocery store might have been grown in such a system, Mullins said.

A hydroponic system is a fast, clean method for growing lettuce, he explained. Plant nutrients are circulated through the system 24 hours a day from a fish tank, while water from that tank is filtered and returned to the tank.

“We use tilapia in our aquaponic systems,” Mullins said. “They’re really great for these systems because they are hardy and can withstand the conditions they’re kept in and grow easily and quickly. They also taste good.”

The system has troughs or gutter channels through which water moves from the fish tank to the plants and then back to the tank. It takes 40 days to harvest lettuce, Mullins said.

“It is necessary to have adequate light for this system, so add grow lights to suspend above if your system needs more light,” he said. “You only need a small tank with 15 to 20 tilapia in it. You could actually use a storage tub instead of a tank, and you want to cover the tank so the fish do not escape.”

The water temperature should be kept at 85 degrees using the heater in the fish tank. The filter attached to the aquatic pump will remove solid material so it doesn’t reach the plants.

Aquaponic kits are available for about $350 in stores or online and can be made from scratch using PVC pipe for $50 to $100, Mullins said.

For more information, visit the Virginia Cooperative Extension website at
Contact Mullins at 804-524-5834.

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