Tag Archives: roots

May 13, 2021

Defining Hemp: Classifications, Policies & Markets, Part 2

By Darwin Millard

In Part 1 of this series we answered the question: What is “hemp”; and addressed some of the consequences of defining “hemp” as a thing. In Part 2, I will explore this topic in more detail and provide some commonsense definitions for several traditional hemp products based on a classification approach rather than separating “cannabis” from “hemp”.

Classifications, Specifications, and Test Methods – Establishing Market Protections for Hemp Products Through Standardization

Does making a distinction between “hemp” and “cannabis” make it easier to protect the interests of the seed and fiber markets?

On the face of it, this question seems obvious. Yes, it does.

Up to this point in history, the bifurcation of the cannabis plant into resin types and non-resin types has served to provide protections for the seed and fiber markets by making it easier for producers to operate, since the resins (the scary cannabinoids, namely d9-THC) were not involved. Today, however, the line in the sand, has been washed away, and “hemp” no longer only refers to non-resin producing varieties of the cannabis plant.

The structure of cannabidiol (CBD), one of 400 active compounds found in cannabis.

As more and more hemp marketplaces come online with varying limits for d9-THC the need for standardization becomes even more pressing. Without standardization, each marketplace will have its own requirements, forcing businesses looking to sell their products in multiple jurisdictions to comply with each region’s mandates and adds a significant level of burden to their operations.

Providing an internationally harmonized definition for hemp is an important first step but allowing the d9-THC limit to vary from jurisdiction to jurisdiction has some unintended (or intended) consequences (#NewReeferMadness). These discrepancies between legal marketplaces will inevitably lead to the establishment of global trade regions; where, if your product cannot meet the definition of “hemp” in that region, then you could effectively be barred from participating in it.

A process which has already started. Harmonizing around 0.3% is great for the US, Canada, and European Union, but what about other stakeholders outside of these markets?

And, at what point does the conflict of hemp from one region with a d9-THC content of 0.3% and hemp from another region with a d9-THC content of 1% being sold into the same market become a problem?

Perhaps a better long-term solution for protecting the market interests of “hemp product” stakeholders would be to establish specifications, such as identity metrics, total cannabinoid content, especially d9-THC, and other quality attributes which have to be verified using test methods for a product to be classified as “hemp”. This system of standards (classifications, specifications, and test methods) would allow for more innovation and make it significantly easier for cannabis raw materials that meet these specifications to find a use rather than being sent to the landfill. Bolstering advancements and opening the door for more market acceptance of the cannabis plant, its parts, and products.

An Alternative Approach to Defining Hemp

Below are some proposed definitions related to common terminology used in the hemp marketplace based on the concept that there are no hemp plants, there are only cannabis plants that can be classified as hemp, and hemp products are simply cannabis products that meet certain specifications to allow them to be classified and represented as hemp.

Hemp, n—commercial name given to a cannabis plant, its parts, and products derived therefrom with a total d9-THC content no more than the maximum allowable limit for the item in question. (Maybe not the best definition, but it makes it clear that not only does the limit for d9-THC vary from jurisdiction to jurisdiction it varies from product type to product type as well.)
Hemp flower, n—commercial name for the inflorescence of a cannabis plant that can be classified as hemp.
Hemp seed, n—commercial name for the seeds of a cannabis plant which are intended to be used to grow another cannabis plant that can be classified as hemp.
Hempseed, n—commercial name for the seeds of a cannabis plant which are intended to be used as food or as an ingredient in food.
Hemp seed oil, n—commercial name for the oils expressed from the seeds of a cannabis plant.
Hemp seed cake, n—commercial name for the solid material byproduct generated during the expression of the oil from the seeds of a cannabis plant.
Hemp flour/meal/dietary-fiber, n—commercial name for the powdered seed cake of a cannabis plant intended to be used as a food or as an ingredient in food with a protein content no more than 35% by weight.
Hemp protein powder, n—commercial name for the powdered seed cake of a cannabis plant intended to be used as a food or as an ingredient in food with a protein content between 35% and 80% by weight.
Hemp protein isolate, n—commercial name for the powdered seed cake of a cannabis plant intended to be used as a food or as an ingredient in food with a protein content above 80% by weight.
Hemp fiber, n—commercial name for the cellulosic-based natural fibers of a cannabis plant.
Hemp shives, n—commercial name for the hurd of a cannabis plant which have been processed to defined specifications.
Hempcrete, n—commercial name for a solid amalgamation of various aggregates and binders, typically comprised of the hurd (shives) of a cannabis plant and lime.

The d9-THC limits for each product were purposefully omitted because these specifications still need to be defined for each product type. Leaving the d9-THC limit up to each authority having jurisdiction, however, is not the answer. It is fine if you comply with a lower d9-THC limit and want to sell into a market with a higher d9-THC limit, but what do you do if you are above the limit for the market you want to sell into? For now, you lose out on potential revenue.

I am not advocating that everyone starts selling “hemp” as “cannabis,” or vice versa, far from it. I am advocating for a more commonsense and inclusive approach to the marketplace though. One that would allow for the commercialization of materials that would normally be going to waste.

To me it is simply logical. There are no hemp plants, there are only cannabis plants that can be classified as hemp. There are no hemp products, there are only cannabis products that can be classified as hemp. In order for a cannabis product to be marketed, labeled, and sold as a hemp product, i.e. to be classified as a hemp, it would need to meet a set of specifications and be verified using a set of test methods first. But fundamentally the product would be a cannabis product being certified as “hemp”. And that is the shift in thinking that I am trying to get across.

Exclusionary Actions – Disenfranchising Stakeholders

The cannabis plant is an amazing plant and to fully capitalize on the potential of this crop we have to start allowing for the commercialization of cannabis raw materials that are not controlled by the UN Single Conventions, i.e. the seeds, stalks, roots, and leaves when not accompanied by the fruiting tops or the resin glands. Not to do so disenfranchises a significant number of stakeholders from participating in established legal avenues of trade for these goods. A concept proposed and endorsed the ASTM D37 in the published standard D8245-19: Guide for Disposal of Resin-Containing Cannabis Raw Materials and Downstream Products.

If you are stakeholder in the hemp marketplace, you may feel threatened by the idea of the market getting flooded with material, but how are the demands of the so called “green economy” going to be met without access to more supply? Organic hemp seed for food production is scarce but there is plenty of conventional hemp seed for the current demand, but what happens when hempmilk is positioned to displace soymilk in every major grocery store? To feed the growth of the human population and allow for a transition to a truly “green economy,” we need to ensure that the policies that we are putting in place are not excluding those looking to participate in the industry and disenfranchising stakeholders from burgeoning marketplaces, nor alienating a segment of the marketplace simply because their plant cannot be classified as “hemp”.

Until next time…

Live long and process.

April 29, 2021

Defining Hemp: Classifications, Policies & Markets, Part 1

By Darwin Millard

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What is “hemp”?

The word “hemp” has many meanings. Historically the term has been used as the common name for the Cannabis sativa L. plant. Just like other plants, the cannabis plant has two names, a common name, hemp, and a scientific name, Cannabis sativa L. After the ratification of the UN Single Conventions on Narcotic Drugs and Psychotropic Substances, in 1961 and 1972 respectively, the term started to be used to distinguish between resin producing varieties of the cannabis plant and non-resin producing varieties of the cannabis plant. Nowadays the term is generally used to refer to cannabis plants with a delta-9-tetrahydrocannabinol (d9-THC), a controlled substance, content equal to or less than the maximum allowable limit defined by each marketplace.

Tetrahydrocannabinol (THC), just one of hundreds of cannabinoids found in cannabis.

In the United States and Canada, the limit is defined as 0.3% on a dry weight bases, and until November 2020, in the European Union, the limit was defined as 0.2%. After years of effort the “hemp” industry in Europe was successfully able to get the limit raised to 0.3% to be in line with the United States and Canada – creating the largest global trade region for hemp products. But there exist several marketplaces around the world where, either through the consequences of geographic location or more progressive regulations, the d9-THC content in the plant can be substantially higher than 0.3% and still considered “hemp” by the local authority.

To address these variances, ASTM International’s Technical Committee D37 on Cannabis has been working on a harmonized definition of hemp, or industrial hemp, depending on the authority having jurisdiction, through the efforts of its Subcommittee D37.07 on Industrial Hemp. The following is a proposed working definition:

hemp, n—a Cannabis sativa L. plant, or any part of that plant, in which the concentration of total delta-9 THC in the fruiting tops is equal to or less than the regulated maximum level as established by an authority having jurisdiction.

Discussion: The term “Industrial Hemp” is synonymous with “Hemp”.

Note: Total delta-9 THC is calculated as Δ⁹-tetrahydrocannabinol (delta-9 THC) + (0.877 x Δ⁹-tetrahydrocannabinolic acid).

This definition goes a long way to harmonize the various definitions of hemp from around the world, but it also defines “hemp” as a thing rather than as a classification for a type of cannabis plant or cannabis product. This is a concept rooted in the regulatory consequences of the UN Single Conventions, and one I strongly disagree with.

The definition also leaves the total d9-THC limit open-ended rather than establishing a specified limit. An issue I will address further in this series.

Can “hemp products” only come from “hemp plants”?

If you are an invested stakeholder in the traditional “hemp” marketplace, you would say, yes.

But are there such things as “hemp plants” or are there only cannabis plants that can be classified as “hemp”? (The definition for hemp clearly states that it is a cannabis plant…)

There is no distinction between the cannabinoids, seeds, and fibers derived from a cannabis plant that can be classified as “hemp” and those derived from a cannabis plant that cannot. The only difference is the word: “cannabis,” and the slew of negative connotations that come along with it. (Negative connotations that continue to be propagated subconsciously, or consciously, whenever someone says the “hemp plant” has 50,000+ uses, and counting, and will save the world because it’s so green and awesome, but not the “cannabis plant”, no that’s evil and bad, stay away! #NewReeferMadness)

The declaration that “hemp products” only come from “hemp plants” has some major implications. “Hemp seeds” can only come from “hemp plants”. “Hemp seed oils” can only come from “hemp seeds”. “Hemp fibers” can only come from “hemp plants”. Etc.

What does that really mean? What are the real-world impacts of this line of thinking?

Flat out it means that if you are growing a cannabis plant with a d9-THC content above the limit for that plant or its parts to be classified as “hemp”, then the entire crop is subjected to the same rules as d9-THC itself and considered a controlled substance. This means that literal tons of usable material with no resin content whatsoever are destroyed annually rather than being utilized in a commercial application simply because a part or parts of the plant they came from did not meet the d9-THC limit.

Some of the many products on the market today derived from hemp

It is well known that d9-THC content is concentrated in the glandular trichomes (resin glands) which are themselves concentrated to the fruiting tops of the plant. Once the leaves, seeds, stalks, stems, roots, etc. have been separated from the fruiting tops and/or the resin glands, then as long as these materials meet the authority having jurisdiction’s specifications for “hemp” there should be no reason why these materials could not be marketed and sold as “hemp”.

There are several reasons why a classification approach to “hemp plants” and “hemp products” makes more long-term sense than a bifurcation of the “cannabis” and “hemp” marketplaces, namely from a sustainability aspect, but also to aid in eliminating the frankly unwarranted stigma associated with the cannabis plant. #NewReeferMadness

That said, say you are a producer making shives from the stalks of cannabis plants that can be classified as “hemp” and then all of a sudden, the market opens up and tons of material from cannabis plants that cannot be classified as “hemp,” that was being sent to the landfill, become available for making shives. Would you be happy about this development? Or would you fight tooth and nail to prevent it from happening?

In this segment, we looked at the history of the term “hemp” and some of the consequences from drawing a line in the sand between “cannabis” and “hemp”. I dive deeper into this topic and provide some commonsense definitions for several traditional hemp products in Part 2 of Defining Hemp: Classifications, Policies & Markets.

June 5, 2017

Applications for Tissue Culture in Cannabis Growing: Part 3

By Aaron G. Biros

4 Comments

In the first part of this series, we introduced some relevant terms and principles to tissue culture micropropagation and reviewed Dr. Hope Jones’ background in the science of it. In the second part, we went into the advantages and disadvantages of using mother plants to clone and why tissue culture could help growers scale up. In the third part of this series, we are going to examine the five steps that Dr. Jones lays out to successfully micropropagate cannabis plants from tissue cultures.

Cleaning – Stage 0

Explant cuttings are obtained from mother plants. The cuttings are further separated into smaller stem pieces with a single node.

Micropropagation includes 5 stages. “Stage 0 is the preparation of mother plants and harvest of cuttings for the explant material,” says Dr. Jones. “To ensure the best chance of growing well in culture, those ladies [the mom’s] should be cleaned up and at their best. And hopefully not stressed by insects or pathogens.” She says growers should also make sure the plants are properly fertilized and watered before harvesting explants. “Obtaining the explants is done with a clean technique using new disposable blades and gloves,” says Dr. Jones. “Young shoot tips are harvested and placed in labeled, large Ziploc bags with a small amount of dilute bleach and surfactant solution, then placed in a cooler and taken to the lab.” This is a process that could be documented with record keeping and data logs to ensure the same care is taken for every explant. “Once in the lab, working in the sterile environment of the transfer hood, the cuttings are sterilized, typically with bleach and a little surfactant, and then rinsed several times with sterile water,” says Dr. Jones. Once they reach the sterile environment, Dr. Jones removes the leaves and cuts the stem down to individual nodes.

Establishment – Stage 1

Establishment essentially means waiting for the shoots to develop. Establishing the culture requires an absolutely sterile environment, which is why the first step is so important. “Proper explant disinfection is equally as important is the control parameters of the facility itself,” says Dr. Jones. Mother plants are not grown in sterile facilities, but in an environment that is invariably contaminated with dust, which harbors micro-organisms, insects and other potential sources of contamination, including human handling. We discussed some of this in Part 2.

Explants, once sterilized and placed in the culture vessel, must establish to the new aseptic conditions. “Basically Stage 0 ends when the explants are cleaned and placed in the vessel. Stage 1 begins on the shelf while we patiently sit, watch and wait for the shoot growth,” says Dr. Jones. “Successful establishment means we properly disinfected the explants because the cultures do not become contaminated with bacteria or fungi and new shoot growth emerges.”

Multiplication – Stage 2

Stage 2 involves subculturing an explant to produce new shoots

This stage is rather self-explanatory as multiplication simplified means generating many more shoots per explant. In order to create a large number of plants needed for meeting the demand of weekly clone orders, Dr. Jones can break up, or subculture, one explant that contains multiple numerous new shoots. “Let’s say one vessel, which originally started with 4 explants each developed four new shoots. Working in the hood, I remove each explant from the vessel and place it on a sterile petri dish. Now I can divide each explant into 4 new explants and then place the four new explant cuttings into their own vessel. In this example, we started with one vessel with 4 explants,” says Dr. Jones. “Which when subcultured 4-6 weeks later, we now have 4 vessels with 16 plants.” This is instrumental in understanding how tissue culture micropropagation can help growers scale without the need for a ton of space and maintenance. From a single explant, you can potentially generate 70,000 plants after 48 weeks, according to Dr. Jones. “Starting with not 1, but 10 or 20 explants would significantly speed up multiplication.” Using tissue culture effectively, one can see how a grower can exponentially increase their production.

Rooting – Stage 3

“When the decision is made to move cultures to the rooting stage, we typically need to subculture the plantlets to a different media formulated to induce rooting,” says Dr. Jones. “In some instances, the media is very dark, and that’s because of the addition of activated charcoal.” Using activated charcoal, according to Dr. Jones, helps darken the rooting environment, which closely mimics a normal rooting environment. “It helps remove high levels of cytokinin and other possible inhibitory compounds,” says Dr. Jones. Cytokinins are a type of plant growth hormone commonly used to promote healthy shoot growth, but it is important to make sure the culture contains the right ratio of hormones, including cytokinin and auxin for maximum root and shoot development. Dr. Jones suggests that growers research their own media formulation to ensure nice, healthy roots develop and that no tissue dies in the process. “With everything I grow in culture, when it comes to media, in any stage and with all new strains, I run some simple experiments in order to refine the media used,” says Dr. Jones. She puts a special focus on the concentrations and ratios of plant hormones in formulating her medias.

After harvesting and multiplying, these explants are ready for rooting

“We commonly think of auxin’s role in rooting, but it’s also important in leaves and acts as a regulator of apical shoot dominance,” says Dr. Jones. “So having no auxin may not be ideal for the shooting media used in Stages 1 and 2.” Auxin is a plant hormone that can help promote the elongation of cells, an important step in any plant’s growth. “And cytokinins are typically synthesized in the root and moves through xylem to shoots to regulate mitosis as well as inducing lateral bud branching, so again finding that nice balance between these two hormones is key.”

Acclimation & Hardening Off – Stage 4

“When plants have developed good looking healthy roots, it’s time to pop the top,” says Dr. Jones. This means opening the vessel, another risk for contamination, which is why having a clean environment is so crucial. “The location of these vessels needs to be tightly controlled for light, relative humidity, temperature and cleanliness.” In the culture, sugar is a main ingredient in the medium, because the growing explants are not very photosynthetically active. “By opening the lid of the vessel, carbon dioxide is introduced to the environment, which promotes and enhances photosynthesis, really getting the plants ready for cultivation.”

Harvesting explant material from mother plants

The very final step in tissue culture micropropagation is hardening, which involves the formation of the waxy cuticle on the leaves of the plant, according to Dr. Jones. This is what preps the plant to actually survive in an unsterile environment. “The rooted plants are removed from the culture vessel, the media washed off and placed in a potting mix/matrix or plug and kept in high humidity and low light,” says Dr. Jones. “Now that there is no sugar, contamination is no longer a threat, and these plants can be moved to the grow facility.” She says conditioning these plants can take one or two weeks. Over that time, growers should gradually increase light intensity and bring down the relative humidity to normal growing conditions.

Overall, this process, if done efficiently, can take roughly eleven weeks from prepping the explants to acclimation and hardening. If growers perform all the steps correctly and with extra care to reduce risks of contamination, one can produce thousands of plants in a matter of weeks.

In the fourth and final part of this series, we are going to dive into implementation. In that piece, we will discuss design principles for tissue culture facilities, equipment and instrumentation and some real-world case studies of tissue culture micropropagation.

March 29, 2017

Understanding Dissolved Oxygen in Cannabis Cultivation

By Aaron G. Biros

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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.