Tag Archives: science

March 29, 2017

Understanding Dissolved Oxygen in Cannabis Cultivation

By Aaron G. Biros

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.

Charlie Hayes, biochemist and owner of Advanced Treatment Technologies

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.

Their treatment system includes check valves that are OSHA and fire code-compliant.

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.

October 6, 2016

The Nerd Perspective

Detecting the Undetectable

By Amanda Rigdon

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In my last column, I took a refreshing step out of the weeds of the specifics behind cannabis analyses and took a broader, less technical look at the cannabis industry. I had envisioned The Nerd Perspective being filled with profound insights that I have had in the cannabis industry, but I have realized that if I restricted this column to insights most would consider profound…well…there would not be many articles. So in this article, I want to share an insight with you, but not one that is earth shattering. Instead, I want to talk about a simple concept in a way that might help you think a little differently about the results your lab generates, the results you have to pay for or even the results printed on a cannabis product you might purchase.

This article is all about the simple concept of concentration – the expression of how much of something there is in relation to something else. We use expressions of concentration all the time – calories per serving, percent alcohol in beer, even poll results in the presidential election circus. Cannabis is not excluded from our flippant use of concentration terms – percent cannabinoid content, parts-per-million (ppm) residual solvents, and parts-per-billion (ppb) pesticides. Most of us know the definition of percent, ppm, and ppb, and we use these terms all the time when discussing cannabis analytical methods. During my career in analytical chemistry, it has occurred to me that parts per billion is a really infinitesimal amount…I know that intellectually, but I have never tried to actually visualize it. So being the nerd that I am, I went about comparing these often-used concentration terms visually in my kitchen.

I started by preparing a 1% solution of food coloring paste in water. This was accomplished by weighing out 5g of the food coloring and dissolving it into 500mL of water (about one teaspoon into a pint). The resulting solution was so dark it was almost black:

The picture above expresses the low end of what we care about in terms of cannabinoid concentration and a pretty normal value for a high-concentration terpene in cannabis.

I then took one teaspoon of that mixture and dissolved it into 1.32 gallons of water (5mL into 5000mL), resulting in a 10ppm solution of green food coloring in water:

I did not expect the resulting solution to be so light colored given the almost-black starting solution, but I did dilute the solution one thousand times. To put this into perspective, 10ppm is well above many state regulatory levels for benzene in a cannabis concentrate.

I then took one teaspoon of the almost-colorless 10ppm solution and dissolved that into another 1.32 gallons of water, resulting in a very boring-looking 10ppb solution of green food coloring in water:

Obviously, since I diluted the almost-colorless 10ppm solution a thousand times, the green food coloring cannot be seen in the picture above. As a reference, 10ppb is on the low end of some regulations for pesticides in food matrices, including – possibly – cannabis. I know the above picture is not really very compelling, so let’s think in terms of mass. The picture above shows eleven pounds of water. That eleven pounds of water contains 50 micrograms of food coloring…the weight of a single grain of sand.

To expand on the mass idea, let’s take a look at the total mass of cannabis sold legally in Colorado in 2015 – all 251,469 pounds of it. To express just how staggeringly small the figure of 10ppb is, if we assume that all of that cannabis was contaminated with 10ppb of abamectin, the total mass of abamectin in that huge amount of cannabis would be just 1.143g – less than half the mass of a penny.

To me, that is an extremely compelling picture. The fact is there are instruments available that can measure such infinitesimal concentrations. What’s more, these tiny concentrations can be measured in the presence of relatively massive amounts of other compounds – cannabinoids, terpenes, sugars, fats – that are always present in any given cannabis sample. The point I’d like to make is that the accurate measurement of trace amounts of cannabis contaminants including pesticides and residual solvents is an astounding feat that borders on magical. This feat is not magic though. It requires extremely delicate instrumentation, ultra-pure reagents, expert analysts, and labor-intensive sample preparation. It is far from trivial, and unlike magic, requires a large investment on the part of the laboratories performing this feat of science. Other industries have embraced this reality, and the cannabis industry is well on its way toward that end…hopefully this article will help put the job of the cannabis analytical lab into perspective.

September 21, 2016

Cannabis, Soil Science and Sustainability Part II: The ‘Roots’ of Sustainable Cultivation

By Drew Plebani

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The modern chemical agricultural approach is based on the assumption that chemical science has discovered all facets of plant nutritional requirements. It is clear that the traditional NPK approach to plant/soil systems has its limitations, both from an ecological perspective and in terms of its ability to create nutrient-dense food.

Soil and plant systems have existed together for millions of years and have evolved the capacity to coexist in a way that is mutually beneficial. Plants have been fed and evolved with these biological and environmental stimuli over millennia.

Looking to the geologic record for evidence, we can see that it shows that invertebrates, fungi and early vascular plants appeared on land roughly 400 million years ago, the first seed bearing plants about 360 million years ago and the first flowering plants 130 million years ago. What does this mean? The soil food web has been in existence for millions of years and significant evidence exists that plants and soil biology have co-evolved together for millennia.

geologictimescale — The Geologic Time Scale

Between mineral rich soils and the soil food web, this natural system has been able to create and provide significant plant available nutrients, certainly enough to facilitate the successful life cycle of many species. Clearly from an evolutionary context this system has been able to facilitate maximum genetic expression and the ongoing evolution of biologic species.

In the not-too-distant past, agricultural fertilization practices were based on the existence of a diversity of plant and animal byproducts, animal manures, green manures, etc. These were reintroduced to the system and combined with the appropriate biologic populations, resulting in the decomposition of these organic material inputs and their conversion into plant-available nutrients.

An overview of traditional farming practices provides substantial evidence that farming has been occurring for at least 10,000 years. Why, with such a long history of symbiotic interactions between biologic species, are we now witnessing the mass deterioration of arable land, and agricultural commodities containing lower nutritional value?

Mycelium, the vegetative part of a fungus bacteria colony, seen breaking through rock. — Together, indigenous mycelium and plant roots seen turning rock into soil

An interesting common question among the conventional farming community, when the topic of organics or sustainability comes up, is “how are you going to feed the world?” Well that goal certainly will not be well served by the development of shelf stable, but low nutrient-dense foods. A greater volume of low nutrient-value foods certainly does not seem like a winning approach. Supporting agricultural systems that encourage the development of sustainable systems via locally produced, nutrient-dense food is a good start.

And the same holds true for cannabis. In fact, the parallels between the production of high quality nutrient dense foods and high quality cannabis products are quite significant.

Nutrient density in crops results from balanced, mineral rich soils, and a diversity of organic materials and biologic life, these elements provide the framework to facilitate the creation of a highly functional, biologic nutrient cycling system. A highly functional soil system results in more nutrient-dense crops, which contain measurably larger quantities of different phytonutrients, vitamins, minerals, flavonoids, and terpenes as compared to a system operating at a lower level of biologic efficiency.

commercialcultivator — Nutrient-dense cannabis flowers

Benefits that have been observed from nutrient-dense crops are: more pest and disease resistance in the vegetative and fruiting stages, greater yield, more complex and intense flavors and a longer shelf life.

Ultimately advancement in any cultivation system means finding and defining limiting factors in the given system. The objective should be ensuring the maximum biologic vitality of the components of said system and its outputs. Practically speaking, in order to enable the full genetic potential of biologic species, this means identifying and working toward the removal of limiting factors. Minimizing or entirely alleviating the factors that limit maximum plant growth will undoubtedly net positive gains and must be an integral component to any sustainable cultivation strategy.

commcultivator3 — Cannabis growing in a polyculture

The Earth has provided us with a highly successful, multi-million-year-old biologic system, capable of providing abundant plant available nutrients on demand, a dynamic which must be integral to appropriate and intelligent systems design.

In the pursuit of sustainability, perhaps it is time to return to our roots and begin to pursue dynamics that are mutually beneficial to all forms of biologic life.

In the next article, we will take a step back from viewing sustainability through the lens of soil and plant specific cultivation methodologies, and focus on the broader context of sustainability in cultivation systems. We will look at sustainability from the context of operational efficiency, and provide a case study from a 400-light commercial indoor cannabis operation. The case study will provide evidence that, in order to achieve higher levels of sustainability, both cultivation strategies and operational efficiency must be factored into the equation. As we will see, true sustainability is created through the efficient design, incorporation, use and management of system elements, all of which can, when appropriately designed, work together to create improved efficiency for the system.

June 29, 2016

Going Beyond the Strain Names with PotBot

By Aaron G. Biros

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David Goldstein, co-founder and chief executive officer of PotBotics, launched a medical cannabis recommendation engine called PotBot with the goal to better inform patients to target their conditions with more accurate recommendations based on scientific research. “This is a tool to help move the market away from the thousands of strain names that are mainly just marketing or branding indicators,” says Goldstein. The medical application is designed to inform patients on peer-reviewed data, research on the treatment of their ailments with cannabis and the specific cannabinoids that are necessary for treating their condition. They began development on PotBot in October of 2014, launching the beta version to 400 users in November of 2015. On April 20^th, 2016, Goldstein launched officially in the Apple Store, and the program will be available on Android in July.

goldstein potbot — David Goldstein (left) alongside co-founder, Baruch Goldstein (right)

Rather than focusing on strain names, PotBot focuses on the cannabinoid values to help patients gain an understanding of the correlation between which compounds might best target their condition. “This is a great tool for patients trying to familiarize themselves with what strains might work best,” says Goldstein. “For example, insomnia patients generally need cannabis with higher CBN levels, so we first educate the patient on cannabinoid ranges to shoot for and what strains might help. PotBot would recommend the strain Purple Urple because it is an indica found to have higher CBN values,” adds Goldstein. The program goes into great detail with the patient’s preferences including everything down to consumption methods so they know why it might recommend certain strains.

A screenshot showing a recommended cannabinoid ratio for a patient

The recommendation tool is accessible via kiosks at dispensaries, on a desktop version for the computer as well as on the Apple Store for iPads and iPhones. “I do not see it as a way of replacing budtenders, rather supplementing them with knowledge,” says Goldstein. PotBot is designed as a tool to supplement the budtender’s understanding of cannabis, so the budtender does not need to know everything off the top of their head or recommend strains based on anecdotal information, according to Goldstein.

Goldstein’s team at PotBotics performed extensive research prior to launching PotBot, spending two years doing strain testing to develop the program. “There is currently no regulatory body [for strain classification] so we took it upon ourselves to work with the best testing laboratories for truly robust analyses and properly vetted growers to get the most valid data,” says Goldstein. “The current strain classification system and nomenclature is rather unscientific so we focus on cannabinoid values and soon we will be able to incorporate terpene profiles in the recommendation.” Moving away from the common focus on taste, smell and other qualitative values, they focus on medical attributes of cannabinoid profiles because they have the most peer-reviewed research available today.

As an OEM, the company designed the tool to work with each dispensary’s inventory, to provide recommendations for strains that a patient can access on site, however anyone can access the recommendation tool for free at PotBot.com. Goldstein’s company and their mission represent an important development in the cannabis industry; this could begin a key transition from thousands of understudied strain names to a more scientific and calculated method to treating patients’ conditions with cannabis.

January 27, 2016

From The Lab

Cannabis Research in Israel: Meeting with Dr. Raphael Mechoulam

By Seth Wong

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I had the pleasure of visiting the famous Dr. Raphael Mechoulam last month at his Hebrew University office just outside of Jerusalem, Israel. For those who may not have heard of him, Dr. Mechoulam is essentially the godfather of the endocannabinoid system. He is best known for his work in isolating and totally synthesizing delta-9 tetrahydrocannabinol (THC). Dr. Mechoulam is one of the leading recognized scientists in our field. Much of his work is focused on the nervous system, specifically how various acids, and particularly cannabinoids, bind to the nervous system and thus their effect on humans.

Dr. Mechoulam is a humble man whose energetic demeanor belies his age. He speaks six languages and continues working regularly even at the age of 86. His mind is as sharp as any 25 year old and, while our meeting was short, it lacked nothing in content.

Dr. Raphael Mechoulam (right) and Seth Wong (left) in the Dr.'s Hebrew university office. — Dr. Raphael Mechoulam (right) and Seth Wong (left) in the Dr.’s Hebrew university office.

His discoveries in cannabis have not been his only accolades and only represent about a third of his work in his accomplished life time. He has a vast number of papers and studies related to fatty and amino acids and their effect on the brain. The underlying principles of all of Dr. Mechoulam’s areas of study are similar and he has equally distinguished himself in these fields as he has in the realm of cannabis. Because of it’s taboo nature and the limited amount of sophisticated scientific research that cannabis has been subject to, Dr. Mechoulam is more widely recognized for this specific focus.

During our brief hour-long meeting, we discussed the impact of cannabinoids on cancer patients and bone marrow transplants, his cannabis research on schizophrenia as well as the role cannabis plays in diabetes patients – all topics on which he has volumes of published research but stressed the point that more research needs to be done; we have only scratched the surface.

Dr. Mechoulam is an inquisitive man who is always investigating, digging, and striving to understand more about the effects of cannabis, fatty, and amino acids on the brain. When asked what charge the cannabis and medical industries need to pursue, he stressed the need for more scientific studies to investigate the impact of cannabis not just on the brain but the entire human body, as well as the need for grants to help promote those studies. Dr. Mechoulam specifically stressed the importance that these studies employ scientific vigor in a responsible and legal manner.

He is man of high moral ground, inquisitive nature, and a thorough investigator. I am privileged and humbled to have met him and heed his call to bring sophisticated and responsible scientific studies to the forefront of the Cannabis Green Rush.