This is part one of our series on challenges of growing organically.
Written by Tinia Pina
Spending the last seven years on research has not only introduced insights critical to our organic cycling science approach but also to learning how we can enhance crop growth using vegetative waste using resource-efficient methods. More importantly, we were able to place ourselves in the position of farms and growers in understanding the pain points of working with biologicals in a recirculating system in such a way that void the risk of introducing food safety-related pathogens, labor inefficiencies and additional costs.
The goal has always been to create a cultivation method that is comparable to the yields of conventional, synthetic mineral salts while increasing a farm’s bottom line using food waste as the mechanism.
Below is an outline of our learnings:
High nitrogen in fertilizer = High protein build up
High nitrogen introduced by animal-based products (e.g. fish emulsion, manure, hydrolyzed poultry litter) often lead to protein build up causing abhorrent smells and clogged systems. Coagulants tend to form from the biofilms of animal-based fertilizers because of the microorganisms within are competing for oxygen. The biofilm would then accumulate at the oxygen source such as air diffusers or tubes and growing media, forcing farms to dump the water after sterilizing their systems with hydrogen peroxide. Not only is this wasteful but this imposes operational downtime to perform system maintenance.
Furthermore, animal-based inputs tend to be more pathogen prone, leading to the risk of E.coli outbreaks, making growing organically even more of a challenge, considering the health implications. Lastly, these products often have too high of a sodium content which can lead to plant toxicity and crop burn, and the need to implement a flushing cycle prior to harvest to rid the plant of any residual, unused salts.
Slower break down of organic compounds = Slower access to water soluble organic hydroponic nutrients
The mineralization time for microbes to break down organic compounds and convert them into a water soluble form that can be readily available to the plant is significant. There is a fine balance of water chemistry, nutrient chemistry, and the plants’ nutrient needs that must be taken into consideration here when growing organically.
Whereas, in a soil environment, there is an ecosystem of microorganisms that would naturally catalyze this process. However, in a soilless farm, the lack of these microbial synergies and inconsistent oxygen availability makes it difficult to mineralize in an efficient manner. On average, this aerobic process for a purely plant-based organic hydroponic nutrient source may take 7-10 days, creating a lead time and again operational inefficiencies with not being able to continuously use the nutrients.
Remaining solid organic matter = More filtration needed
When growing organically, solids remaining from the usage of animal-based products require filtration. If filtration is not performed then the build-up of organic matter contributes to the competition for biological oxygen, creating anaerobic zones on the solid matter that contributes to pathogenic bacteria and strong pH variations.
Different chemistry balances = Varying rates of nitrification of organic nitrogen compounds
As there is a unique balance between water chemistry, nutrient chemistry, and the plant’s nutrient needs, there is also a balance involving the nitrification of organic nitrogen compounds. The same microbes that catalyze the mineralization process described above when growing organically also create the conversion of ammonia into nitrites and then subsequently into nitrates. This is a microbial process that if not optimized can lead to inefficiencies related to longer operational time and an accumulation of unused organic matter in a soilless system.
Consistency of organic feedstock = EC and pH variabilities
Lastly, the consistency of the type of organic feedstock and blend can largely impact all of the aforementioned points. Not all food waste is created equal and if the ratios of specific food waste or other organic nutrient inputs are not taken into consideration this can lead to the high EC and pH variability and additional supplementation requirements (input costs) that has made most farms cautious of adopting organic cultivation methods to date.
So What Now for Organic Farming?
Is it possible for soilless farms that want to venture into the world of organics to find an organic hydroponic nutrient that avoids all of these challenges? We say yes. Undoubtedly, there are many different aspects to take into consideration when understanding the challenges of growing organically. For many farms, the risk is too high – and we get it. But in Part 2 of this series, we will convey our approach resolving and mitigating many of these points, opening up an opportunity for farms to dip their feet even deeper into the world of growing organically. In the meantime, if you have any thoughts or questions, we’re always here to help.