Soilless Food Production

Image credit: Ponic Greens

Producing food through hydroponics is a centuries-old technology that has found new popularity at the heart of Oklahoma’s emerging sustainable food production industry. While hydroponic and aquaponic farms have vast visual differences, the similarities to conventional farming resonated during the Soilless Protected Food Production Systems Conference at Oklahoma State University.

When state and national hydroponics producers, as well as university and industry experts convened in Stillwater, Oklahoma, the topics of discussion focused on topics conventional farmers know well — from climate change and rising production costs to fusarium and nematodes.

“The biggest problem in this industry is that you’re trying to work against an industry that has been established for years,” said Richard Tyler, owner of Native Oklahoma Aquaponic Harvest Farm. “We’re not the pioneers of aquaponics; it’s been around since 500 B.C.”

Tyler and his wife Jackie spoke about the challenges their Vian, Oklahoma, operation faces, as well as the victories they have achieved in more than 10 years of aquaponic production.

“We’ve got a 10,000-square foot greenhouse that uses polycarbonate,” Tyler said. “For Oklahoma, what we have found out is the environmental control is challenging — lettuce wilts very easily.”

The Tylers’ operation began in a small, homemade hoop house as an effort to provide local families with access to fresh foods. In the early stages, NOAH Farm could feed 65 families and today they can harvest up to 400 heads of lettuce per day.

Initially, NOAH Farm added fish to their production to lower input costs and provide a richer base for their produce. The added protein source for local families with the addition of their tilapia production was a bonus.

“With aquaponics when you recirculate the water using the fish, you actually feed the good, protein-rich food,” Tyler said. “With that food, it goes through the nitrification process and is high in ammonia in the water when it’s discharged and high in nitrite, but as it goes through the filtration and bacteria exchange process it actually creates a perfect balance of fertilized water.”

Water usage and electricity usage in aquaponic systems like NOAH Farm are kept as low as possible to lower costs and enhance the sustainability of the system. In rural areas like Vian, acquiring enough water from rural outlets might appear to be a concern, but the Tyler’s system requires a surprisingly small amount of water.

“In California, they might use 20 to 24 gallons of water to produce a single head of lettuce, and we can do the same with just one cup,” Tyler said. “They’re doing 50 to 65 days in the field, and we’re doing 40 to 45 days in the winter here.”

Tyler said area farms that produce fruits and vegetables struggle to compete for pricing with out-of-state conventional production but long term he believes aquaponic production to be a viable sustainable farming option, especially in the state of Oklahoma.

“Oklahoma is in the best growing area in the United States,” Tyler said. “I know it’s hard to believe but we have the most stable climate and temperatures of anybody in the world.”

Aquaponic Production Concerns

Greenhouses may be more controlled environments than an open field but often greenhouse-grown plants are no less susceptible to insects and diseases than plants in an open field. Conversely infections or infestations could spread more quickly and with more destruction indoors.

“You have an entirely different set of problems in a greenhouse, particularly in a hydroponic greenhouse, compared to the field,” said OSU plant pathologist John Damicone.

While diseases are no less common indoors than out, the variety of disease options is widely different.

“You generally have less foliar diseases in a greenhouse because you’re sheltered from the rain,” Damicone said. “One that we do have is powdery mildew on crops that you normally wouldn’t see on crops out in the field.”

Temperature and moisture conditions in greenhouses can change quickly, and a precarious balance needs to be maintained to limit diseases. Even in different conditions, a few challenges conventional farmers are familiar with also plague greenhouse-based producers.

“We have a strain of fusarium called fusarium crown and root rot,” Damicone said. “It’s almost entirely a greenhouse problem and where we have fusarium out in the field, this other strain is more prominent inside.”

Fusarium crown and root rot produces a canker that rots the roots and lower stems, as opposed to regular fusarium where the stem would remain fairly green, Damicone said.  Even in soilless systems like aquaponics, challenges that would typically be soil-borne can present themselves.

“We also, believe it or not, have nematodes in hydroponic systems,” Damicone said. “Root knot nematodes were transferred into one greenhouse through recycled perlite root bags.”

Because challenges like disease and pest infestations can get out of hand so quickly in a greenhouse environment, active scouting can be an extremely important aspect.

“Scouting provides means of protecting pest presence early in the crop production cycle,” said OSU entomologist Eric Rebek. “When the pest population gets out of hand and we have heavy pressure on our crops, it’s often times too late to do much of anything other than discarding the crop and starting over.”

While greenhouse level scouting might appear easier than field-level scouting due to the smaller area, monitoring aquaponics systems requires frequent, detailed reports.

“You may need to dedicate one full-time employee as a scout,” Rebek said. “This should be done very frequently — a minimum of two times per week but preferentially more.”

While Rebek said scouting is typically a large production cost for hydroponic and aquaponic producers, it is essential to maintaining a safe, healthy environment for sustainably producing food.

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