Hydroponics, Aquaponics, Vertical farming. What are they? Can these methods of growing produce be deemed “organic”? The USDA’s National Organics Standards Board (NOSB) met recently and this was one question they considered but tabled for later review. I don’t know about you, but I have been confused by these terms and I’ve also read some claims about these methods and wondered what was true and what was marketing material. Are these methods of growing produce going to save the world from starvation? Is the produce really organic, as some producers claim? Are they really better for us and the earth than field farming? Is the vitamin and mineral content of plants grown without soil is as good as field grown crops? So I decided I needed to learn more about them. I’ll start with some definitions and then talk about pros and cons. Note that my research was focused on produce grown commercially, not home gardening.

  • Hydroponic growing is probably the best known to most of us. It’s been in commercial use for a long time, and you no doubt have eaten produce grown this way many times. (You know those tomatoes and strawberries you eat in January?) “Hydroponics is a subset of hydroculture, the method of growing plants without soil, using mineral nutrient solutions in a water solvent. Terrestrial plants may be grown with only their roots exposed to the mineral solution, or the roots may be supported by an inert medium, such as perlite or gravel.” [1]
  • Aquaponics is a newer method and from what I could find, not widely commercialized. It “is the marriage of aquaculture (raising fish) and hydroponics (the soil-less growing of plants) that grows fish and plants together in one integrated system. The fish waste provides an organic food source for the growing plants and the plants provide a natural filter for the water the fish live in.” [2]
  • Vertical farming is the newest method to get widespread attention although it has been around a while too. It “is the practice of producing food in vertically stacked layers, such as in a skyscraper, used warehouse, or shipping container. The modern ideas of vertical farming use indoor farming techniques and controlled-environment agriculture (CEA) technology, where all environmental factors can be controlled. These facilities utilize artificial control of light, environmental control (humidity, temperature, gases…) and fertigation.” [3] Vertical growing uses generally the same setup as hydroponics but in stacked trays.

Generally speaking, they are all based on the same principles. Provide a base for the seeds and seedlings, feed them nutrients, and provide light. They differ in the type of containers and different ways of providing nutrients and light, and even within the same category of method there may be differences in practice. These methods share some advantages over farming in dirt.

  • They use less water.
  • They are less likely to need pesticides.
  • It is possible to grow plants all year round, not just in warmer months.
  • Produce can be grown closer to the urban market, so less transportation costs, pollution, and time.
  • Plants grow faster and can be sold/delivered the same day as harvest.
  • Since all three methods can be operated indoors, production is less subject to weather events.
  • All these methods take less space than ground farming proportionate to yield.

But there are also negatives to these methods.

  • Primary is the high electrical usage to power grow lights, fans, pumps, and heating or cooling systems. To grow enough food using these methods to feed the populations adherents claim they can would take far more power than is generated today.
  • There’s a limit to what kinds of plants will grow in these setups; for instance root vegetables will not grow in these methods and producing large quantities of grain would require extremely large systems, so claims of being able to feed cities via these systems are overblown.
  • Hydroponics and vertical systems are not growing plants just in water; they need nutrient inputs which may not be organic and not better than synthetic fertilizers used on fields.
  • In aquaculture the fish waste provides nutrients for the plants but the fish still have to be fed, and most fish meal is made from ocean fish, which may have high levels of mercury or other contaminants.
  • The cost of produce grown this way puts it out of reach of many people it is intended to feed.
  • In hydroponic farming, periodic replacement of the solution results in large amounts of fertilizer-rich water to dispose of that can promote algal growth and be a threat to aquatic ecosystems.
  • Some people find that the flavor of crops raised without soil is watered down or less prominent than in soil grown crops.

Proponents of these methods claim their produce is organic because they don’t (usually) use pesticides. But that is not the only definition of “organic”. Cornucopia, staunch defenders of the organic label, state “Language in the Organic Foods Production Act and the current federal regulations clearly indicate that good soil stewardship is a prerequisite to qualify for organic certification. In 2010 the NOSB reinforced the soil prerequisite by passing recommendations that reiterated the prohibition of hydroponic certification. The National Organic Program never acted on these recommendations. Since then, an industry-friendly USDA has allowed some of the largest certifiers, including California Certified Organic Farmers (CCOF) and Quality Assurance International (QAI), to certify hydroponically produced tomatoes, cucumbers, peppers, eggplant, and berries at an alarming rate.” [4] This is very controversial, when one certifier would allow the label and another would not.

Vertical farming, or gardening as some refer to it, also gets a knock from opponents for its even more vast need of power for lights than the other methods. Since the trays of plants are stacked atop each other there is no chance of all the plants getting natural light even if the roof is clear and there are large windows, so all the plants need plenty of artificial life to grow. Is creating the amount of additional power that would be needed for large-scale operations the best thing for the environment? Some people claim solar or wind power could help, but the plants grown in these methods need continuous light so in areas where the sun or wind is inconsistent this would not help.

One of the arguments for soilless growing is that the world is running out of arable land. This is not quite true. Worldwide there is more than enough arable land to grow the crops needed to feed the world. But too much land has been devastated by poor management – overgrazing, too many chemicals, poor irrigation management, and modern agricultural practices. “(B)ecause agricultural land is often degraded and almost useless, producers keep on moving to more productive land. Globally, the land used and abandoned in the last 50 years may be equal to the amount of land used today.” [5] Another issue is confined animal feeding operations (CAFOs), with thousands or tens of thousands of cattle or hogs confined to lots. These animals are fed grains which require vast acreage, dedicated to feeding animals which we will eat. If humans were to reduce meat consumption and not expect the price of meat at the grocery to be less than the price of tomatoes, land managers could restore all the land needed for growing food crops. The question of nutritional comparison is inconclusive – some studies find more nutrition in soil crops and some studies report more from soilless crops – there have been few objective studies done.

In conclusion, I do not think huge soilless operations are the answer to world hunger. Better management of what we already have is a more viable option, with soilless-grown produce supplementing field output. These methods also need continuous improvement to reduce the need for electricity and get prices to a level that less affluent people can afford. Finally, I could not consider these methods organic. I feel there is a symbiotic relationship between soil and plants that provides an overall better environment, and that is a big part of what “organic” means for me. How do you feel about this?

 

[1] https://en.wikipedia.org/wiki/Hydroponics

[2] https://www.theaquaponicsource.com/what-is-aquaponics/?v=70f73ee5133f

[3] https://en.wikipedia.org/wiki/Vertical_farming

[4] https://www.cornucopia.org/2016/11/corporate-interests-nosb-wash-hands-organic-soil/?utm_source=eNews&utm_medium=email&utm_content=11.26.16&utm_campaign=HydroMORE

[5] Carey C., Oettli D. (2006) Determining links between agricultural crop expansion and deforestation. A report prepared for the WWF Forest Conversion Initiative.

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