The Classification Gap of Organic Hydroponic Food

Written By Tinia Pina


A few months ago, in July 2016, the US Department of Agriculture (USDA) released a memorandum to the Organic Standards Board (OSB), which reported the findings of the Hydroponic and Aquaponic Task Force (HATF). In the memo, the HATF reinforced earlier findings of the OSB, reiterating that by the very nature of the word, hydroponically grown food cannot be classified as organic.

According to the memo, “The framework of organic farming is based on its foundation of sound management of soil biology and ecology.” Modern organic farming thus entails the “continuous restoration” of soil by adding combinations of manure, compost and natural rock to feed the soil, not the crops. In contrast, hydroponic crops use a soilless substrate such as rockwool, coco coir, hydrocorn, perlite or vermiculite, as the bed for seeds or seedlings. By definition, hydroponic crops do not use soil, and therefore the HATF and USDA found that hydroponically grown food cannot be classified as organic.

In this article, we’ll discuss two topics pertaining to the classification of hydroponic crops grown exclusively with Re-Nuble products, and how we need further research in finding an equivalent classification to “organic” for hydroponically grown food.

Grown in the Ground – Grown in a Nutrient Solution Continuum

The definition of what’s grown in the ground and what’s grown in a nutrient solution is surprisingly difficult to parse. This is because modern day agricultural growing can happen in a variety of hybrid methods. In the chart below, we’ve visualized what the HATF named the “Grown in the Ground – Grown in a Nutrient Solution Continuum” represents. Of the five growing methods named, only the first two (from the left) can ever be certified organic. The other three methods (from the right) can never be certified organic.

Re-Nuble Hydroponic USDA Organic Label

As the graph above shows, there is no distinction among possible hydroponic liquid fertilizer compositions. While the majority of hydroponically grown food uses inorganic inputs, Re-Nuble products are manufactured entirely with inputs that are organic and with biological components derived from the organic certified produce waste that we incorporate. Re-Nuble products are a liquid fertilizer and crops grown only with Re-Nuble products undergo a process similar to crops grown with compost.

The clear delineation between Re-Nuble fertilizers and chemical fertilizers thus presents a classification gap for crops grown with Re-Nuble products. If all of the inputs in a hydroponic system are organic and the system uses a fertilizer that incorporates a biological composting process to grow a crop, shouldn’t the yields be considered organic? Unfortunately, the findings of the HAFT did not offer further information on such a process.


What is “soil”?

Another deceptively complicated concept is defining what is considered “soil”.  The HAFT report cites previous Crops Committee documents, which posed the question of whether growing media that are “predominantly compost and compostable plant materials be considered ‘soil?’”

In this context, such a question is ambiguous, because organic farming is built on the premise of nurturing soil to create “accompanying ecologies”. As the report notes, earthworms, protozoa, fungi, bacteria, antinomycetes and other soil dwelling organisms can exist in compost. Therefore, for all intents and purposes, compost is soil.

We at Re-Nuble thus pose the question – if we use composting-like processes, can our hydroponic fertilizer, when used in a hydroponic system, be an ecological extension of soil?

The HAFT report did say that regulations did not initially “specifically state ‘soil only production’” was required for organic certification, but that the intent of the regulations includes soil in organic certification. The 2010 findings of the OSB did mandate soil be the accepted norm, in line with European regulations. HAFT concedes, however, that standards must be added when classifying soilless growing system yields.


Why Should We Care?

The lack of clarity in the organic classification system for hydroponically grown food poses challenges to Re-Nuble both as a business and as a company with a social mission. The demand for organic produce in the States has been on the rise for the past decade, with 2014 sales totaling USD 5.5 billion, up 72% since 2008. The “organic” certification on produce has a large and measureable value.

Ethically, we have a responsibility to our consumers. One of the main justifications of the lengthy and detailed HAFT report was to bring clarity to consumers on what constitutes “organic” products. With no equal classification to organic, those consuming hydroponically grown food – which is increasingly available across the country – have no way of knowing what their food contains.

Finally, without an equivalent classification, Re-Nuble is unsure of how to help the horticulture industry classify Re-Nuble grown products. If lettuce is grown using our product, can we then use the excess lettuce we grow using our fertilizers and still say our fertilizers use organic inputs? Technically, the answer is no. Practically, we’re unsure. With a social mission of closing the food loop, this question is particularly important.

We propose a new system of classification for hydroponically grown food. An obvious method of classification is whether the used fertilizers contain chemicals or non-plant inputs. Knowing that there is a wide range of hydroponic growing systems, we welcome your thoughts on the issue. In the future, we hope to see the USDA explore the hydroponic “organic” classification question further.


We'd love to hear your thoughts on the above. Please contact us to send us your commentary.