GW Pharmaceuticals scored a significant victory in the United States with its cannabis-based epilepsy drug Epidiolex in mid-April. The company received approval from a U.S. Food and Drug Administration (FDA) panel for its use in treating two forms of drug-resistant epilepsy.
The drug was granted “orphan drug” status in the EU a year ago.Will this be enough to move the conversation forward about cannabis as medicine in the United States?
So what does the future hold for this drug and a company, which has visited this space before? Remember Sativex?. The Company now faces real competition from a raft of companies moving into this space from just about everywhere – both from Canada and of course Europe itself.
The FDA Might be on the Verge of Approving its First Cannabis-Based Drug
It is not like this is either the FDA’s or GW Pharma’s first discussion about the medical efficacy of cannabinoids. Sativex, a mouth spray containing THC, was never granted approval in the United States for the treatment of MS – although it received such approvals in Europe.
If the FDA approves Epidiolex (made from CBD), it will be the first cannabinoid-based drug approved in the United States by the federal agency.
Will this be enough to move the conversation forward about cannabis as medicine in the United States? What will happen in the EU?
A Divergent and Highly Different Drug Market
Will the FDA finally approve at least one form of a CBD-based drug? The chances are that Epidiolex might finally move the agency to approve. However,this is not, despite the hype that the company has made in the press about this, the first cannabinoid-based drug to be approved in the United States. It might be, however, the first drug based on actual natural cannabinoids rather than synthetic ones that it approves for some purpose. Both Cesamet and Dronabinol (or Marinol) are synthetic cannabinoid drugs approved for several conditions from chronic pain caused by chemo to Parkinson’s.
But those who are hoping that this drug approval might open the floodgates at the FDA for startersshould take a pew. While Sativex was not approved in the United States, it was made available after 2011 for MS patients, particularly in Germany, which has the highest rate of MS of any European country. The problem? It was just too expensive for most people to afford – since their insurance would not cover it. And doctors were even more resistant to prescribing than they are now. So even getting a prescription was almost impossible.
That conversation was different in Europe post-2013, and there were people who managed to get a doctor to write a prescription not to mention afford the eye-watering prices sans insurance coverage.
That said, given the choice between whole plant meds, most people still prefer bud cannabis to the spray variety. And in Europe right now, that is what is on the table.
What Will This Mean in the US vs Europe?
In the US, the first thing that FDA approval will mean is drug sales for only one branded drug. That is the cynicism at play here. Furthermore, it also neatly dodges the THC issue.
In Europe? Particularly Germany? This development is not likely to make much of a dent. GW is competing with every single Canadian producer with flower-based oil – and on both the medical and non-medical CBD front. That also now includes local producers. Further, this is a market which prizes genericized drugs over name brands. In France, the distribution of Sativex was held up, primarily because of the row over cost. And who would pay.
It is also unlikely that the FDA approval in the United States will change the discussion either in the US on a federal level – or in Europe.
The most important place this news already made a dent? GW Pharma’s stock price – at least temporarily. It is also a spot of good news the company really needs. In February, the company’s GWP42006 drug designed for focal seizures (drug resistant epilepsy) failed to outperform placebo results and wiped 5% off the company’s stock.
Parts One and Two in this series have defined Good Manufacturing Practices, introduced Hazard Analysis and Critical Control Points (HACCP) and explained the first HACCP step of hazard analysis. A food safety team will typically work from a flow diagram to identify biological, chemical or physical hazards at each step of processing and packaging. Once the hazard is identified, the severity and probability are debated. Hazards with severe consequences or high probability are carried through the HACCP plan as Critical Control Points (CCPs).
Critical Control Points definedHACCP is a do-it-yourself project.
Where exactly will the hazard be controlled? CCPs are embedded within certain steps in processing and packaging where the parameters, like temperature, must be met to ensure food safety. Failure at a CCP is called a deviation from the HACCP plan. The food safety team identifies where manufacturing problems could occur that would result in a product that could cause illness or injury. Not every step is a CCP! For example, I worked with a client that had several locations for filters of a liquid stream. The filters removed food particles, suspended particulates and potentially metal. We went through a virtual exercise of removing each filter one-by-one and talking through the result on controlling the potential hazard of metal. We agreed that failure of the final filter was the CCP for catching metal, but not the other filters. It was not necessary to label each filter as a CCP, because every CCP requires monitoring and verification.
Identification of a CCP starts more documentation, documentation, documentation.
Do you wish you had more reports to write, more forms to fill out, more data to review? No. Nobody wants more work. When a CCP is identified, there is more work to do. This just makes sense. If a CCP is controlling a hazard, you want to know that the control is working. Before I launch into monitoring, I digress to validation.
CCP validationThis is where someone says, “We have always done it this way, and we have never had a problem.”
You want to know if a critical step will actually control a hazard. Will the mesh of a filter trap metal? Will the baking temperature kill pathogens? Will the level of acid stop the growth of pathogens? The US had a major peanut butter recall by Peanut Corporation of America. There were 714 Salmonella cases (individuals) across 46 states from consumption of the contaminated peanut butter. Imagine raw peanuts going into a roaster, coming out as roasted peanuts and being ground into butter. Despite the quality parameters of the peanut butter being acceptable for color and flavor, the roasting process was not validated, and Salmonella survived. Baking of pies, pasteurization of juice and canning all rely on validated cook processes for time and temperature. Validation is the scientific, technical information proving the CCP will control the hazard. Without validation, your final product may be hazardous, just like the peanut butter. This is where someone says, “We have always done it this way, and we have never had a problem.” Maybe, but you still must prove safety with validation.
The hazard analysis drives your decisions.
Starting with the identification of a hazard that requires a CCP, a company will focus on the control of the hazard. A CCP may have one or more than one parameter for control. Parameters include time, temperature, belt speed, air flow, bed depth, product flow, concentration and pH. That was not an exhaustive list, and your company may have other critical parameters. HACCP is a do-it-yourself project. Every facility is unique to its employees, equipment, ingredients and final product. The food safety team must digest all the variables related to food safety and write a HACCP plan that will control all the hazards and make a safe product.
Meeting critical limits at CCPs ensures food safety
The HACCP plan details the parameters and values required for food safety at each CCP.The HACCP plan identifies the minimum or maximum value for each parameter required for food safety. A value is just a number. Imagine a dreadful day; there are problems in production. Maybe equipment stalls and product sits. Maybe the electricity flickers and oven temperature drops. Maybe a culture in fermentation isn’t active. Poop happens. What are the values that are absolutely required for the product to be safe? They are often called critical limits. This is the difference between destroying product and selling product. The HACCP plan details the parameters and values required for food safety at each CCP. In production, the operating limits may be different based on quality characteristics or equipment performance, but the product will be safe when critical limits are met. How do you know critical limits are met?
CCPs must be monitored
Every CCP is monitored. Common tools for monitoring are thermometers, timers, flow rate meters, pH probes, and measuring of concentration. Most quality managers want production line monitoring to be automated and continuous. If samples are taken and measured at some frequency, technicians must be trained on the sampling technique, frequency, procedure for measurement and recording of data. The values from monitoring will be compared to critical limits. If the value does not reach the critical limit, the process is out of control and food safety may be compromised. The line operator or technician should be trained to know if the line can be stopped and how to segregate product under question. Depending on the hazard, the product will be evaluated for safety, rerun, released or disposed. When the process is out of control, it is called a deviation from the HACCP plan.
A deviation initiates corrective action and documentation associated with the deviation. You can google examples of corrective action forms; there is no one form required. Basically, the line operator, technician or supervisor starts the paperwork by recording everything about the deviation, evaluation of the product, fate of the product, root cause investigation, and what was done to ensure the problem will not happen again. A supervisor or manager reviews and signs off on the corrective action. The corrective action form and associated documentation should be signed off before the product is released. Sign off is an example of verification. Verification will be discussed in more detail in a future article.
My thoughts on GMPs and HACCP were shared in a webinar on May 2nd hosted by CIJ and NEHA. Please comment on this blog post below. I love feedback!
By Alison J. Baldwin, Brittany R. Butler, Ph.D., Nicole E. Grimm 1 Comment
With legalization of cannabis for medicinal and adult use occurring rapidly at the state level, the industry is seeing a sharp increase in innovative technologies, particularly in the area of cannabis extraction. Companies are developing novel extraction methods that are capable of not only separating and recovering high yields of specific cannabinoids, but also removing harmful chemicals (such as pesticides) from the concentrate. While some extraction methods utilize solvents, such as hydrocarbons, the industry is starting to see a shift to completely non-solvent based techniques or environmentally friendly solvents that rely on, for example, CO2, heat and pressure to create a concentrate. The resulting cannabis concentrate can then be consumed directly, or infused in edibles, vape pens, topicals and other non-plant based consumption products. With companies continually seeking to improve existing extraction equipment, methods and products, it is critical for companies working in this area to secure their niche in the industry by protecting their intellectual property (IP).
Comprehensive IP protection for a business can include obtaining patents for innovations, trademarks to establish brand protection of goods and services, copyrights to protect logos and original works, trade dress to protect product packaging, as well as a combination of trade secret and confidentiality agreements to protect proprietary information and company “know-how” from leaking into the hands of competitors. IP protection in the cannabis space presents unique challenges due to conflicting state and federal law, but for the most part is available to cannabis companies like any other company.
Federal trademark protection is currently one of the biggest challenges facing cannabis companies in the United States. A trademark or service mark is a word, phrase, symbol or design that distinguishes the source of goods or services of one company from another company. Registering a mark with the U.S. Patent and Trademark Office (USPTO) provides companies with nationwide protection against another company operating in the same space from also using the mark.
As many in the industry have come to discover, the USPTO currently will not grant a trademark or service mark on cannabis goods or services. According to the USPTO, since cannabis is illegal federally, marks on cannabis goods and services cannot satisfy the lawful use in commerce requirement of the Lanham Act, the statute governing federal trademark rights. Extraction companies that only manufacture cannabis-specific equipment or use cannabis-exclusive processes will likely be unable to obtain a federal trademark registration and will need to rely on state trademark registration, which provides protection only at the state-level. However, extractors may be able to obtain a federal trademark on their extraction machines and processes that can legitimately be applied to non-cannabis plants. Likewise, companies that sell cannabis-infused edibles may be able to obtain a federal trademark on a mark for non-cannabis containing edibles if that company has such a product line.
Some extraction companies may benefit from keeping their innovations a trade secretSince the USPTO will not grant marks on cannabis goods and services, a common misconception in the industry is that the USPTO will also not grant patents on cannabis inventions. But, in fact, the USPTO will grant patents on a seemingly endless range of new and nonobvious cannabis inventions, including the plant itself. (For more information on how breeders can patent their strains, see Alison J. Baldwin et al., Protecting Cannabis – Are Plant Patents Cool Now? Snippets, Vol. 15, Issue 4, Fall 2017, at 6). Unlike the Lanham Act, the patent statute does not prohibit illegal activity and states at 35 U.S.C. § 101 that a patent may be obtained for “any new and useful process, machine, manufacture, or composition of matter, or any new and useful improvement thereof.”
For inventions related to extraction equipment, extraction processes, infused products and even methods of treatment with concentrated formulations, utility patents are available to companies. Utility patents offer broad protection because all aspects related to cannabis extraction could potentially be described and claimed in the same patent. Indeed, there are already a number of granted patents and published patent applications related to cannabis extraction. Recently, U.S. Patent No. 9,730,911 (the ‘911 patent), entitled “Cannabis extracts and methods of preparing and using same” that granted to United Cannabis Corp. covers various liquid cannabinoid formulations containing very high concentrations of tetrahydrocannabinolic acid (THCa), tetrahydrocannabinol (THC), cannabidiol (CBD), THCa and cannabidiolic acid, THC and CBD, and CBD, cannabinol (CBN), and THC. For example, claim 1 of the ‘911 patent recites:
A liquid cannabinoid formulation, wherein at least 95% of the total cannabinoids is tetrahydrocannabinolic acid (THCa).Properly crafted non-disclosure agreements can help further ensure that trade secrets remain a secret indefinitely.
Although the ‘911 patent only covers the formulations, United Cannabis Corp. has filed a continuation application that published as US2017/0360745 on methods for relieving symptoms associated with a variety of illnesses by administering one or more of the cannabinoid formulations claimed in the ‘911 patent. This continuation application contains the exact same information as the ‘911 patent and is an example of how the same information can be used to seek complete protection of an invention via multiple patents.
An example of a patent application directed to solvent-based extraction methods and equipment is found in US20130079531, entitled “Process for the Rapid Extraction of Active Ingredients from Herbal Materials.” Claim 1 of the originally filed application recites:
A method for the extraction of active ingredients from herbal material comprising: (i) introducing the herbal material to a non-polar or mildly polar solvent at or below a temperature of 10 degrees centigrade and (ii) rapidly separating the herbal material from the solvent after a latency period not to exceed 15 minutes.
Claim 12, covered any equipment designed to utilize the process defined in claim 1.
Although now abandoned, the claims of this application were not necessarily limited to cannabis, as the claims were directed to extracting active ingredients from “herbal materials.”
Other patents involve non-toxic extraction methods utilizing CO2, such as Bionorica Ethics GMBH’s U.S. Patent No. 8,895,078, entitled “Method for producing an extract from cannabis plant matter, containing a tetrahydrocannabinol and a cannabidiol and cannabis extracts.” This patent covers processes for producing cannabidiol from a primary extract from industrial hemp plant material.
There have also been patents granted to cannabis-infused products, such as U.S. Patent No. 9,888,703, entitled “Method for making coffee products containing cannabis ingredients.” Claim 1 of this patent recites:
A coffee pod consisting essentially of carbon dioxide extracted THC oil from cannabis, coffee beans and maltodextrin.
Despite the USPTO’s willingness to grant cannabis patents, there is an open question currently regarding whether they can be enforced in a federal court (the only courts that have jurisdiction to hear patent cases). However, since utility patents have a 20-year term, extractors are still wise to seek patent protection of the innovations now.
Another consideration in seeking patent protection for novel extraction methods and formulations is that the information becomes public knowledge once the patent application publishes. As this space becomes increasingly crowded, the ability to obtain broader patents will decline. Therefore, some extraction companies may benefit from keeping their innovations a trade secret, which means that the secret is not known to the public, properly maintained and creates economic value by way of being a secret. Properly crafted non-disclosure agreements can help further ensure that trade secrets remain a secret indefinitely.
Regardless of the IP strategy extractors choose, IP protection should be a primary consideration for companies in the cannabis industry to ensure the strongest protection possible both now and in the future.
Demand for cannabis extracts, in particular vaping products, is at an all-time high. People want good oil, and they want to know something about the quality of it. It is therefore time to take a step back and consider the process from plant to cartridge. What is the current industry standard for cannabis extraction, what constitutes quality and where might we need to make some adjustments?
Right now, “clear” oil is hot. Customers have been led to believe that a pale gold extract is synonymous with the best possible cannabis concentrate, which is not necessarily the case. Producing a 95% pure THC extract with a translucent appearance is neither a great scientific feat nor a good representation of the whole cannabis flower. Moreover, it runs counter to the current trend of all-natural, non-processed foods and wellness products.
“My carrots are organic and fresh from the farmers market, my drink has no artificial sweeteners and my honey is raw, but my cannabis oil has undergone a dozen steps to look clear and still contains butane.”Cannabis is a fascinating plant. It is the basis of our livelihood, but more importantly, it enhances the quality of life for patients. The cannabis plant offers a plethora of medicinally interesting compounds. THC, CBD and terpenes are the most popular, but there are so many more. As of the most recent count, there are 146 known cannabinoids1. Cannabinoids are a group of structurally similar molecules2, including THC and CBD, many of which have shown biological activity3.
Then there are terpenes. These are the smaller molecules that give cannabis its distinct smell and flavor, over 200 of which have been identified in cannabis4. But wait, there’s more. The cannabis plant also produces countless other metabolites: flavonoids, alkaloids, phenols and amides5. All these components mixed together give the often-cited entourage effect6,7.
Current industry standards for cannabis oil extraction and purification stand in marked contrast to the complexity of the plant’s components. Due to an unsophisticated understanding of the extraction process and its underlying chemistry, cannabis oil manufacturers frequently produce oil of low quality with high levels of contamination. This necessitates further purifications and clean up steps that remove such contaminants unfortunately along with beneficial minor plant compounds. If one purifies an extract to a clear THC oil, one cannot also offer the full spectrum of cannabinoids, terpenes and other components. Additionally, claiming purities around 95% THC and being proud of it, makes any self-respecting organic chemist cringe8.
The labor-intensive, multi-step extraction process is also contrary to “the clean-label food trend”, which “has gone fully mainstream”9. Exposing the cannabis flower and oil to at least half a dozen processing steps violates consumer’s desire for clean medicine. Furthermore, the current practice of calling supercritical-CO2-extracted oils solvent-less violates basic scientific principles. Firstly, CO2 is used as a solvent, and secondly, if ethanol is used to winterize10, this would introduce another solvent to the cannabis oil.
We should reconsider our current extraction practices. We can offer cannabis extracts that are free of harmful solvents and pesticides, give a better, if not full, representation of the cannabis plant and meet the patients’ desire for clean medicine. Realizing extracts as the growth-driver they are11 will make us use better, fresher starting materials12. Understanding the underlying science and learning about the extraction processes will allow us to fine-tune the process to the point that we target extract customized cannabis concentrates13. Those, in turn, will not require additional multi-step purification processes, that destroys the basis of the entourage effect.
The cannabis industry needs to invest and educate. Better extracts are the result of knowledgeable, skilled people using precise instruments. Backroom extraction with a PVC pipe and a lighter should be horror stories of the past. And only when the patient knows how their medicine is made can they make educated choices. Through knowledge, patients will understand why quality has its price.
In short, over-processing to make clear oil violates both the plant’s complexity and consumers’ desires. Let us strive for pure extracts, not clear. Our patients deserve it.
 Prof. Meiri; lecture at MedCann 2017
 ElSohly, Slade, Life Sciences2005, 539
 Whiting, et. al.,JAMA.2015, 2456
 Andre, Hausman, Guerriero, Frontiers in Plant Science2016, 19
Hazard analysis and critical control points (HACCP) is a robust management system that identifies and addresses any risk to safety throughout production. Originally designed for food safety through the entire supply chain, the risk assessment scheme can ensure extra steps are taken to prevent contamination.
The FDA as well as the Food Safety and Inspection Service currently require HACCP plans in a variety of food markets, including high-risk foods like poultry that are particularly susceptible to pathogenic contamination. As California and other states develop and implement regulations with rigorous safety requirements, cannabis cultivators, extractors and infused product manufacturers can look to HACCP for guidance on bolstering their quality controls. Wikipedia actually has a very helpful summary of the terms referenced and discussed here.
The HACCP system consists of six steps, the first of which being a hazard analysis. For Dr. Markus Roggen, vice president of extraction at Outco, a medical cannabis producer in Southern California, one of their hazard analyses takes place at the drying and curing stage. “When we get our flower from harvest, we have to think about the drying and curing process, where mold and bacteria can spoil our harvest,” says Dr. Roggen. “That is the hazard we have to deal with.” So for Dr. Roggen and his team, the hazard they identified is the potential for mold and bacteria growth during the drying and curing process.
The next step in the HACCP system is to identify a critical control point. “Correct drying of the flower will prevent any contamination from mold or bacteria, which is a control point identified,” says Dr. Roggen. “We also have to prevent contamination from the staff; it has to be the correct environment for the process.” That might include things like wearing gloves, protective clothing and hand washing. Once a control point is identified, the third step in the process is to develop a critical limit for those control points.
A critical limit for any given control point could be a maximum or minimum threshold before contamination is possible, reducing the hazard’s risk. “When we establish the critical limit, we know that water activity below 0.65 will prevent any mold growth so that is our critical limit, we have to reach that number,” says Dr. Roggen. The fourth step is monitoring critical control points. For food manufacturers and processors, they are required to identify how they monitor those control points in a written HACCP plan. For Dr. Roggen’s team, this means using a water activity meter. “If we establish the critical control point monitoring, water activity is taken throughout the drying process, as well as before and after the cure,” says Dr. Roggen. “As long as we get to that number quickly and stay below that number, we can control that point and prevent mold and bacteria growth.”
When monitoring is established and if the critical limit is ever exceeded, there needs to be a corrective action, which is the fifth step in a HACCP plan. In Dr. Roggen’s case, that would mean they need a corrective action ready for when water activity goes above 0.65. “If we don’t have the right water activity, we just continue drying, so this example is pretty simple,” says Dr. Roggen. “Normal harvest is 7 days drying, if it is not dry enough, we take longer to prevent mold or bacteria growth.”
The sixth step is establishing procedures to ensure the whole system works. In food safety, this often means requiring process validation. “We have to double check that our procedure and protocols work,” says Dr. Roggen. “Checking for water activity is only a passive way of testing it, so we send our material to an outside testing lab to check for mold or bacteria so that if our protocols don’t work, we can catch those problems in the data and correct them.” They introduced weekly meetings where the extraction and cultivation teams get together to discuss the processes. Dr. Roggen says those meetings have been one of the most effective tools in the entire system.
The final step in the process is to keep records. This can be as simple as keeping a written HACCP plan on hand, but should include keeping data logs and documenting procedures throughout production. For Dr. Roggen’s team, they log drying times, product weight and lab tests for every batch. Using all of those steps, Dr. Roggen and his team might continue to update their HACCP plans when they encounter a newly identified hazard. While this example is simplistic, the conceptual framework of a HACCP plan can help detect and solve much more complex problems. For another example, Dr. Roggen takes us into his extraction process.
Dr. Roggen’s team, on the extraction side of the business, uses a HACCP plan not just for preventing contamination, but for protecting worker safety as well. “We are always thinking about making the best product, but I have to look out for my team,” says Dr. Roggen. “The health risk to staff in extraction processes is absolutely a hazard.” They use carbon dioxide to extract oil, which carries a good deal of risks as well. “So when we look at our critical control points we need to regularly maintain and clean the extractor and we schedule for that,” says Dr. Roggen.
“My team needs respirators, protective clothing, eyewear and gloves to prevent contamination of material, but also to protect the worker from solvents, machine oil and CO2 in the room.” That health risk means they try and stay under legal limits set by the government, which is a critical limit of 3,000 ppm of carbon dioxide in the environment. “We monitor the CO2 levels with our instruments and that is particularly important whenever the extractor is opened.” Other than when it is being opened, Dr. Roggen, notes, the extractor stays locked, which is an important worker safety protocol.
The obvious corrective action for them is to have workers leave the room whenever carbon dioxide levels exceed that critical limit. “We just wait until the levels are back to normal and then continue operation,” says Dr. Roggen. “We updated our ventilation system, but if it still happens they leave the room.” They utilize a sort of double check here- the buddy system. “I took these rules from the chemistry lab; we always have two operators working on the machine on the same time, never anyone working alone.” That buddy check also requires they check each other for protective gear. “Just like in rock climbing or mountain biking, it is important to make sure your partner is safe.” He says they don’t keep records for employees wearing protective gear, but they do have an incident report system. “If any sort of incident takes place, we look at what happened, how could we have prevented it and what we could change,” says Dr. Roggen.
He says they have been utilizing some of these principles for a while; it just wasn’t until recently that they started thinking in terms of the HACCP conceptual framework. While some of those steps in the process seem obvious, and it is very likely that many cannabis processors already utilize them in their standard operating procedures and quality controls, utilizing the HACCP scheme can help provide structure and additional safeguards in production.
Oxygen plays an integral role in plant photosynthesis, respiration and transpiration. Photosynthesis requires water from the roots making its way up the plant via capillary action, which is where oxygen’s job comes in. For both water and nutrient uptake, oxygen levels at the root tips and hairs is a controlling input. A plant converts sugar from photosynthesis to ATP in the respiration process, where oxygen is delivered from the root system to the leaf and plays a direct role in the process.
Charlie Hayes has a degree in biochemistry and spent the past 17 years researching and designing water treatment processes to improve plant health. Hayes is a biochemist and owner of Advanced Treatment Technologies, a water treatment solutions provider. In a presentation at the CannaGrow conference, Hayes discussed the various benefits of dissolved oxygen throughout the cultivation process. We sat down with Hayes to learn about the science behind improving cannabis plant production via dissolved oxygen.
In transpiration, water evaporates from a plant’s leaves via the stomata and creates a ‘transpirational pull,’ drawing water, oxygen and nutrients from the soil or other growing medium. That process helps cool the plant down, changes osmotic pressure in cells and enables a flow of water and nutrients up from the root system, according to Hayes.
Roots in an oxygen-rich environment can absorb nutrients more effectively. “The metabolic energy required for nutrient uptake come from root respiration using oxygen,” says Hayes. “Using high levels of oxygen can ensure more root mass, more fine root hairs and healthy root tips.” A majority of water in the plant is taken up by the fine root hairs and requires a lot of energy, and thus oxygen, to produce new cells.
So what happens if you don’t have enough oxygen in your root system? Hayes says that can reduce water and nutrient uptake, reduce root and overall plant growth, induce wilting (even outside of heat stress) in heat stress and reduce the overall photosynthesis and glucose transfer capabilities of the plant. Lower levels of dissolved oxygen also significantly reduce transpiration in the plant. Another effect that oxygen-deprived root systems can have is the production of ethylene, which can cause cells to collapse and make them more susceptible to disease. He says if you are having issues with unhealthy root systems, increasing the oxygen levels around the root system can improve root health. “Oxygen starved root tips can lead to a calcium shortage in the shoot,” says Hayes. “That calcium shortage is a common issue with a lack of oxygen, but in an oxygen-deprived environment, anaerobic organisms can attack the root system, which could present bigger problems.”
So how much dissolved oxygen do you need in the root system and how do you achieve that desired level? Hayes says the first step is getting a dissolved oxygen meter and probe to measure your baseline. The typical dissolved oxygen probe can detect from 20 up to 50 ppm and up to 500% saturation. That is a critical first step and tool in understanding dissolved oxygen in the root system. Another important tool to have is an oxidation-reduction potential meter (ORP meter), which indicates the level of residual oxidizer left in the water.
Citing research and experience from his previous work, he says that health and production improvements in cannabis plateau at the 40-45 parts-per-million (ppm) of dissolved oxygen in the root zone. But to achieve those levels, growers need to start with an even higher level of dissolved oxygen in a treatment system to deliver that 40-45 ppm to the roots. “Let’s say for example with 3 ppm of oxygen in the root tissue and 6ppm of oxygen in the surrounding soil or growing medium, higher concentrations outside of the tissue would help drive absorption for the root system membrane,” says Hayes.
Reaching that 40-45 ppm range can be difficult however and there are a couple methods of delivering dissolved oxygen. The most typical method is aeration of water using bubbling or injecting air into the water. This method has some unexpected ramifications though. Oxygen is only one of many gasses in air and those other gasses can be much more soluble in water. Paying attention to Henry’s Law is important here. Henry’s Law essentially means that the solubility of gasses is controlled by temperature, pressure and concentration. For example, Hayes says carbon dioxide is up to twenty times more soluble than oxygen. That means the longer you aerate water, the higher concentration of carbon dioxide and lower concentration of oxygen over time.
Another popular method of oxidizing water is chemically. Some growers might use hydrogen peroxide to add dissolved oxygen to a water-based solution, but that can create a certain level of phytotoxicity that could be bad for root health.
Using ozone, Hayes says, is by far the most effective method of getting dissolved oxygen in water, (because it is 12 ½ times more soluble than oxygen). But just using an ozone generator will not effectively deliver dissolved oxygen at the target levels to the root system. In order to use ozone properly, you need a treatment system that can handle a high enough concentration of ozone, mix it properly and hold it in the solution, says Hayes. “Ozone is an inherently unstable molecule, with a half-life of 15 minutes and even down to 3-5 minutes, which is when it converts to dissolved oxygen,” says Hayes. Using a patented control vessel, Hayes can use a counter-current, counter-rotational liquid vortex to mix the solution under pressure after leaving a vacuum. Their system can produce two necessary tools for growers: highly ozonized water, which can be sent through the irrigation system to effectively destroy microorganisms and resident biofilms, and water with high levels of dissolved oxygen for use in the root system.