Smackdown: Hydroponic vs. Soil-Based Organic Growing
Sustainable-minded growers have been locked in an argument the past few years over whether or not hydroponic or aquaponics systems of growing could ever be considered organic.
In-soil organic growers argue the core philosophy of organics is “feed the soil, not the plant.” If there is no soil to feed, how can it be organic?
This group also argues many soilborne trace minerals and microorganisms contribute to plant health, and little research has been done to prove or disprove their importance, so to certify a soilless system as organic is premature.
On the hydroponic side, growers say if they are using only products labeled organic, isn’t the resulting plant and produce therefore organic?
These points are the more calm version of the debate. Both sides tend to view the other in a jaundiced way.
Some hydroponic growers call the soil-based growers purists, whose beliefs border on religion, not science. On the other side, many organic growers see hydroponic growers as more focused on profit than the quality of the produce.
Money Complicates the Issue
And as that last statement shows, there is a financial component to this debate. Due to consumer demand, organic produce commands higher prices. And if a lot more growers can lay claim to being certified organic, that selling power will be diluted.
There aren’t a lot of certified organic hydroponic producers in the U.S. — fewer than 200 if you include aquaponics, soilless media produce, and traditional hydroponics. But there is a line forming of foreign growers wanting to sell in the U.S. organically.
Growers in almost 30 countries cannot have their hydroponically grown produce certified as organic. Those countries’ laws do not allow it. So growers in the Netherlands, Mexico, and Canada are watching developments in the U.S. closely, wanting to cash in on the premium pricing they can demand with organic certification.
Which is Safer and Tastier?
Both sides claim their produce is safer, healthier, and better tasting.
Take this claim from EZ Gro, a hydroponics supplier:
“Organic farming allows the use of manure as a natural fertilizer. This has caused a recurring health problem due to E. coli and salmonella outbreaks. Hydroponic growers have completely eliminated the need for soil and its microorganisms.”
The Mayo Clinic touts the health benefits of organic produce:
“Studies have shown small to moderate increases in some nutrients in organic produce. The best evidence of a significant increase is in certain types of flavonoids, which have antioxidant properties.”
Sounds like an issue that can be cleared up by university research. But it seems the jury is still out.
Dr. Rachel Tinker-Kulberg, an Aquaponic and Soil Farmer and Consultant, summed it up in a review for AbundanceNC.org of the various studies that have been conducted:
“The results from a study by Treftz, 2015 [Chenin Treftz, Researcher at the University of Nevada, Reno] showed that the ‘healthy’ antioxidant compounds (e.g., Vitamin C, tocopherol, and total polyphenolic compounds) were significantly higher in hydroponically grown strawberries compared to the soil-grown. But the opposite was true for raspberries.
“Interestingly, earlier studies by Premuzic, 1998 [Zdenka Premuzic, Researcher at University of Buenos Aires, Argentina] showed that tomato fruit grown in healthy organic soil (100% or 50% vermicompost) contained more Vitamin C than the same fruit grown hydroponically, while other studies by Buchanan, 2013 [Drew Buchanan, Researcher at the University of Nevada, Reno] showed that hydroponically grown lettuce contained more Vitamin C than soil-grown varieties.”
When it comes to how plants obtain their nutrient content, it’s a matter of straightforward science, says Dr. Merle Jensen, a founder of Controlled Environment Agriculture Center, and a Professor Emeritus at the University of Arizona.
“We have to go with the side of science. The nutrient goes into the plant in the same ionic form, [whether it’s from the soil or from soilless media], period,” he says. “By going with organic hydroponics, we can govern the rhizosphere at will. If we stress the plant at certain times, we can increase the sugar in the fruit.”
A challenge for hydroponic growers using organic products is that plant roots are unable to absorb the product unaided, Jensen says. There needs to be an added step to break down the organic compounds for the plants. Those methods are currently being researched.
USDA Is Stalling on Declaring Sides
The USDA has a role in how volatile the issue of hydroponics and certified organic produce has become. In its twice-yearly meetings, the National Organic Standards Board (NOSB) has deferred making a ruling for two years now, including the most recent meeting last month.
The NOSB makes non-binding recommendations to USDA, which can ignore the suggestions. A previous recommendation to require organic produce to be grown in soil in 2010 was ignored by USDA. Several soilless-media growers are currently certified as organic.
Still, its recommendations carry a lot of weight. By kicking the issue from meeting to meeting, it’s inspiring the two sides to dig in further.
When NOSB deferred its decision during the spring 2016 meeting, it resulted in the watchdog group, Cornucopia Institute, to sue USDA. Here’s how Cornucopia Institute frames it:
“Congress, in passing the Organic Foods Production Act, reserved four positions on the NOSB for individuals who ‘own or operate’ an organic farm. Cornucopia’s lawsuit alleges that two of the board’s four farmer positions are occupied by full-time agribusiness executives, rather than farmers.”
The lawsuit is still working its way through the system, having survived a petition for dismissal from USDA last September.