Foliar tissue analysis is an extremely useful tool for growers managing plant nutrition of cannabis. It falls into two major categories: routine analysis and diagnostic analysis. Routine analysis is for problem prevention, whereas diagnostic analysis is for problem solving.

The routine analysis allows growers to monitor nutrient uptake in the plant during production. This requires a grower to take multiple samples over the entire course of the growing season to identify problems or issues before they become serious concerns.

Growers can use diagnostic analysis to diagnose deficient or toxic nutrients when the plants are displaying negative symptoms. This process helps identify the specific problem and is primarily a corrective tool. Plant tissue analysis is especially useful in determining micronutrient levels in the plant and has a greater level of accuracy than a substrate test using a water-based extraction.

Tissue Analysis Strategies for Cannabis Growers

Routine analysis sampling is a general management tool when the plant is displaying no negative symptoms. The strategy here is to determine the nutrient status of the plant by plotting tissue values over time to ensure that a fertility program is on track.

For example, when growing a cannabis mother stock crop, a grower could collect samples monthly during the time the plant is developing prior to taking cuttings. This would provide valuable information to ensure that plants contain adequate nutrient levels going into the cutting season.

Another valuable strategy could be to sample the plants just before taking cuttings and then periodically over the cutting season. Typically, with other floriculture species, nutrient levels decline over time as cuttings are harvested. Knowing the status of your stock plants enables growers to modify their fertilization practices to the stock plants during the cutting season to help ensure the cuttings are nutritionally charged when growers take them from the plant.

A third monitoring strategy would be to periodically sample the cuttings taken from the stock plant during the cutting season. This will determine if nutrient levels are being maintained in the stock. This will also verify that the cuttings themselves have adequate nutrients.

Each of these nutritional monitoring strategies requires that growers sample each cultivar separately, as nutrient levels can vary with each one. In addition, if there are differences in the plant’s age or fertilization practices, cultivators should sample those blocks of plants separately.

Cultivators sampling plants for diagnostic analysis should sample them individually. To accurately diagnose a nutritional disorder, growers will need to take samples from the affected plant and/or symptomatic portion of the plant. For example, if the lower leaves display toxicity symptoms, then cultivators should sample those leaves. Because the critical lower deficiency ranges and toxic upper ranges for cannabis are not known at this time, if possible, cultivators should collect a “good” control sample to compare to their problem sample.

Understanding Testing Parameters

Generally, a leaf tissue analysis will include the following macronutrients: nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg). (Labs might not include sulfur (S) or may do so at an additional charge.) Tissue analysis also determines the following micronutrient concentrations: boron (B), copper (Cu), iron (Fe), manganese (Mn) and zinc (Zn). Some labs charge extra and require a larger sample amount for molybdenum (Mo) determination, and some will also test for sodium (Na) and chloride (Cl). While Na and Cl are not considered essential for plant production, some fertilizers or source water may contain these nutrients. Cultivators should check with the lab where they are submitting their sample to determine the elements tested and cost.

Sampling Procedure 101

The leaf tissue sample should be representative of the plant or production area being monitored or the problem cultivators wish to analyze. As mentioned above, growers should sample plants of different ages and varieties separately. The process includes:

1. Collecting leaf samples.

• For routine analysis, collect the most recently mature leaf. This leaf is typically three to five leaves down from the growing tip (Fig. 1 above). For a representative sample, take 25 to 30 leaves from five to 10 plants (Fig. 2).
• For diagnostic analysis, sample plants individually, taking leaves from the affected portion of the plant (Fig. 3). Again, if possible, sample a “good” control so that comparisons can be made.

2. Washing and drying leaves.

If the crop has been overhead watered or micronutrients have been foliar applied, gently wash the leaves in distilled water for 20 seconds to remove any surface contaminants. Dry the leaves with paper towels after washing, prior to packaging them.

3. Packaging leaves for analysis.

Send the samples in a paper bag or manila envelope to the commercial lab authorized to analyze cannabis samples (Fig. 4). Label the bag with your name and address. Contact the lab to verify if there are any special requirements for delivery and documentation under current legislation.

4. Delivering the samples.

Immediately send the samples to a lab certified in your state to conduct leaf-tissue analysis. Try to collect the sample at the beginning of the week so delivery will not be delayed over the weekend. If delivery time to the lab (or to a drying oven) is expected to exceed 12 hours, then it’s best to refrigerate or air-dry the samples.

At this point, nutrient sufficiency ranges for cannabis have not been developed for specific growth stage(s). Bryson and Mills (2014) published nutrient ranges for cannabis (Table 1 above). The database for cannabis nutrient sufficiency ranges is still a work in progress and will be further refined over time as scientific studies determine target nutrient levels over the crop's production cycle as well as critical deficiency and toxicity levels. Refinement of tissue standard ranges for cannabis has been a project being studied by the North Carolina Department of Agriculture and Consumer Services, Agronomic Division and North Carolina State University. Those refined values for cannabis mother stock plants grown in a greenhouse just prior to the stage when cuttings would be harvested are also listed in Table 1.

Conclusion

Leaf tissue analysis provides insight into the nutrient status of a cannabis crop. Tissue analysis results will help growers determine if their fertilizer program is on target by providing current nutrient levels in the plant. In addition, tissue testing is one of the best methods for diagnosing nutrient disorders in cannabis.

Brian Whipker, Paul Cockson, James Turner Smith & Hunter Landis are from the Department of Horticultural Science, North Carolina State University, Raleigh, N.C.

The terms cannabinoids, terpenoids and flavonoids may not have the same market appeal as indica or sativa. But many industry experts say these secondary metabolites hold more value to cultivators and their customers than common strain names.

In the September 2019 issue of Cannabis Business Times, senior editor Brian MacIver explored some industry myths and how science is changing the way cultivators make strategic decisions (see the cover story “The Science Void”). It’s a topic that CBT also explored during the 2019 Cannabis Conference.

Andrea Sparr-Jaswa, now science editor at CBT and sister publication Cannabis Dispensary, addressed some of these key issues as the moderator for a panel on “Science That Sells: Debunking the Sativa and Indica Myths and Instead Focusing on Terpenoids, Cannabinoids and Flavonoids” at the 2019 event, which featured Jeremy Plumb, director of production science for Prf Cultivar; Jeremy Sackett, founder and chief science officer of Cascadia Labs; and Dr. Dominick Monaco, general manager at GB Sciences Inc.

Here are some highlights from the panel discussion and a glimpse at what’s to come for Cannabis Conference 2020 taking place at Paris Las Vegas April 21-23, 2020. (Note: the following has been edited for length and clarity.)

On the Indica vs. Sativa Myth

Plumb: We’ve worked for a long time to try to be more relevant at both Farma and now at my role at Prf Cultivar, to try to … expose the ingredients. But the big issue is this: There’s morphology—like the plant structure. And when we look at narrow and broad leaves, from a plant morphology perspective, we can’t easily correlate that with the kinds of chemistry the plant produces. Really, this morphology was the basis for the original taxonomy.

And it’s gone through many waves. But the reality is, we’re in a new era where we have really distinctive features for phytochemistry on one side of the equation and then distinctive features for the morphological development of the plant on the other. But the giant issue happens when we try to connect the two. And really, [we] can never say that the narrow-leaved sativa plant is producing these focusing and euphoriant effects. That’s really going to come down to the molecules and the inventory and the chemistry in that plant.

Sackett: We’ll never find this perfect archetype of (indica/sativa) in the commercial market now. There’s a third category that’s often used, which is “hybrid.” The problem is … they’re all hybrids. These categories that have become popularized … are a bit unfortunate. You see … we have this moment in history to really change people’s lives with the inventory of phytochemistry, [and] we’re seeing really unfortunate labeling of the ingredients or misrepresentations altogether.

Sparr-Jaswa: Yeah, hybridization in the market and just this constant evolution of perpetuating new genetics—which is incredibly exciting—has completely rendered the [indica/sativa] dichotomy meaningless.

On Data Transparency and Targeted Effects

Monaco: If we don’t actually start collecting that [phytochemical] data, we don’t know if it’s actually having effects on therapeutic value for our patients or our customers. There could be a phytol, a sterol, an ester in there that’s causing all of these actual great therapeutic effects. Metabolomics [the study of metabolites’ effects on cells] is definitely where we’re going to find out exactly where the plant and body meet. We always talk about seed-to-sale, right? But we need to talk about seed-to-outcomes … because that’s where we’re going to get all of this actual data … where we’re going to push this forward.

Sackett: And, you know, that outcome at this juncture, as you mentioned, is really patient-based and empowering the patient or adult consumer to really understand what they are consuming. It just takes a little bit of motivation on the retail end. And then, hopefully, empowering the consumer to start tracking their outcome based on these sets of terpene and cannabinoid information that they now have.

Plumb: [Data allows us to] really meet people’s needs and take care of them in a more targeted way. … It always comes back on us to actually report and collect that data in a wholehearted way—to make sure it’s transparent and make sure that it’s not adulterated in any way, and that it’s analyzed correctly. Because, you know, if we start correlating things that aren’t correlatable, then we’re back to square one.

On Navigating Environmental Effects on Phytochemistry

Plumb: The reality is, if you are a producer as I am, you would see an unbelievable range of phytochemistry from one plant as a result of small changes in the environment. So, the kinds of things that contribute to affecting the secondary metabolite profile of drugs the plant is making include: temperature, relative humidity, light intensity, light wavelength, frequency of irrigation, nutrition programs, harvest timing—all sorts of things beyond the genetic material itself.

… So, for people who advocate sun-growing—which I am a huge fan of—we need to absolutely ecologically produce cannabis as … our carbon footprint scales. … But, on the other hand, we really need targeted effects and plants that can produce consistent arrays of phytochemistry in order to meet diverse people’s needs. So, there’s a really important role to play in controlled environment agriculture—in precision agriculture.

Monaco: You know, having cultivated 1.5 million grams every year out of our local Las Vegas facility, I can attest to the fact that it’s very difficult to get batches to be the same. We’ve noticed variance from room to room, time of year. … And having that laboratory data to come and back-end your actual production data to say, “OK, so my VPD went off here or my light shut off here or my CO2 went off and I had to switch out a tank for that day.” ... Knowing those kinds of things and then correlating it with the actual laboratory data is absolutely key if you want to fine-tune your operation.

On Nomenclature and Setting Consumer Expectations

Sackett: And speaking to the standardization of testing labs … there are many national organizations working to set those standards. … The general quality practices of any laboratory are consistent to a food laboratory, a pharmaceutical laboratory. But I’ve sat in rooms where [strain] names were changed just because the marketing team thought it would sell better under this name. I think ... what is in that name is really those phytochemicals. Using that profile to navigate both consumer choices as well as those breeding and cultivation choices is super important.

Plumb: We’re still at a moment where there is an incredible amount of genetic diversity. … And we have an opportunity to actually do an honest inventory and start to represent the products more accurately to consumers. So clearly diminishing the relevance of the strain name is a fundamental part of that and really moving forward the chemovar … is really the most important thing I see happening in terms of being more relevant to a mass market.

Sackett: Moving a product forward with those different claims of experience is a little bit early in my opinion. … And, ultimately, a dream that I have is that somebody can walk into a retail shop and be drawn to a terpinolene-dominant section, a caryophyllene-dominant section, a pinene-dominant section and have those grouped together and be able to make better choices.

So, I really think that we’re at a place where it’s just going to take a while, and we have to be humble and use great science and collaborate and be mature as an industry. And recognize what we don’t know and where we have to go to be able to serve the most people at the deepest level.

Jonathan Katz is managing editor for Cannabis Business Times and Cannabis Dispensary magazines.

When Danielle Rosellison learned that two employees working in the trim room at Trail Blazin’ were taking premium buds from the tops of plants and hiding them in their gloves, she took swift action and terminated them.

“In this business, we’re always thinking about how to mitigate risk,” says Rosellison, CEO of Trail Blazin’, a producer-processor in Bellingham, Wash. “Theft—both internal and external theft—is one of those risks.”

Scant data exists on how often growers and dispensaries are victims of crimes—and even less is known about how often employees are the perpetrators—but there is no question that the high-value, easy-to-sell product is vulnerable to theft.

To complicate matters, traditional risk mitigation strategies, such as insurance, might not offer protection. While cannabis cultivators face multiple risks in their operations, including employee theft, insurance companies exclude coverage for losses from criminal conduct and illegal activities, according to a 2019 report from Finance Markets, Institutions and Instruments. In at least one case, a federal district court declared an insurance policy void because cannabis is still considered illegal at the federal level, according to the report.

The lack of available remedies for theft suggests that prevention may be the best way cultivators can protect themselves from related losses. Cannabis Business Times recently spoke with several growers and security experts who offered these nine security measures that cultivators can adopt to protect themselves against employee theft.

1. Go beyond the basics: State-mandated security regulations, such as video surveillance, are not enough to prevent internal theft, according to Barry Davidson, director of strategic engagement for 3 Sixty Secure Corp., a global security company based in Almonte, Ontario, Canada, with expertise in the cannabis industry. Davidson suggests cannabis companies first conduct a risk analysis with a security professional to determine which technologies are appropriate for their operations. A combination of systems, including access control, motion sensors and alarm monitoring, are often necessary to safeguard against various types of threats, he says. “Multiple layers of security are critical, and while a lot of these decisions come down to dollars and cents, creating a plan and investing in it now could lead to big savings down the road if it prevents even one instance of theft.”

2. Hire the right people: When it comes to hiring staff, Rosellison believes solid hiring practices are the first line of defense against internal theft. Rosellison places a premium on applicants who appear to be optimistic, dependable and hardworking over those with specific skill sets to work in Trail Blazin’s 10,000-square-foot indoor grow. Focusing on desirable personality traits creates a culture of trust and collaboration, which lessens the incentive to steal, she says.

At Sunnabis Farms in Humboldt County, Calif., CEO Wendy Kornberg conducts background checks on all prospective hires. The practice, she believes, helps filter out those who could pose a risk to her operation. “If you got arrested for weed, it doesn’t mean you won’t get the job,” she says. “But if you got arrested for armed robbery, I’m probably not going to hire you.”

3. Cultivate a strong company culture: At Legacy Nursery, a wholesale cannabis nursery in Modesto, Calif., owner Jennina Chiavetta works hard to treat employees well. She believes that fair pay, good benefits and treating workers with respect helps ensure that the staff working at the nursery feel valued. “If someone doesn’t feel like they’re being treated well, that’s when theft happens,” she says. “You want to make the work and the environment appealing enough that theft isn’t something that is constantly on their minds.”

4. Monitor, monitor, monitor: State regulations often require cameras in all areas of a cannabis operation. Davidson calls cameras “overt preventive measures” because workers know they are being watched, which lessens their motivation to skim cash or crops.

Kornberg mounts trail cameras in strategic spots outdoors to monitor Sunnabis’ farm and greenhouse. The cameras might not prevent theft but, she says, “At least we’ll know who did it.”

At Trail Blazin,’ all areas are under 24-hour surveillance. Rosellison says cameras allow her to see what’s happening in all areas of the operation—from trimming to packaging. From her office, she can see feeds from all 48 cameras on the screen.

5. Hire armed security: For Chiavetta, a solid security plan includes hiring armed guards for both her indoor and outdoor facilities. Protecting the plants from would-be thieves, she believes, is worth the investment, but protections need to be put in place to ensure the guards do not make off with the goods. “The guards know all of the security protocols,” she says. “Hiring two guards, who hopefully aren’t in cahoots, lessens the risk that one could flip.”

6. Lock it up: Kornberg knows cannabis growing on her farm and greenhouse are harder to protect than cannabis grown in a warehouse for one simple reason: Locks. You can lock up a building and install keypads on doors, but outdoor grows are more vulnerable to theft. Alarms can also be deterrents, but Davidson warns that alarming each door might be more of a problem than a solution, explaining, “There is potential for false alarms, and if you get too many, the human response will be to ignore them.”

7. Invest in a vault: Thanks to the growing number of credit unions in Washington State eager to work with cannabis businesses, the number of cash transactions is falling, according to Rosellison. In fact, Trail Blazin’ receives checks for almost 95% of its transactions—but when cash comes in, it goes straight to the bank.

California’s financial institutions aren’t so cannabis-friendly: All of the cash collected at Sunnabis Farms is stored under lock and key. “Leaving cash strewn about it just a bad idea,” Kornberg says. “No matter how trustworthy someone seems, that level of temptation might be too much.”

8. Track transportation: Both cash and cannabis are vulnerable during transport, says Clint Bryer, sales manager for Safety Vision. The Texas-based mobile surveillance company works with multiple cultivators to install cameras that record all of the happenings both inside and outside the vehicle. “Preventing employee theft is the No. 1 reason cannabis companies want the technology,” Bryer says. “When employees can see the cameras and know they’re being watched, it prevents something from happening.” When Legacy Nursery starts production in 2020, Chiavetta plans to handle all of the deliveries as a precaution against employee theft.

9. Protect your intellectual property: The hard work that goes into breeding quality genetics and bringing back classic strains has Chiavetta concerned about theft of intellectual property. All employees who work at Legacy Nursery sign both non-disclosure and non-compete agreements as part of their onboarding paperwork, and Chiavetta worked with an attorney to file trademarks, licensing agreements and patents to protect her intellectual property from ill-intentioned employees. “If you’re robbed before you make a dollar, there goes all of your planning,” she says.

The bottom line, says Davidson, is that no security measure will prevent internal theft on its own, explaining, “Technical measures [such as alarms, vaults and cameras] need to work hand-in-hand with process measures [such as strong hiring practices and standard operating procedures] to protect against theft.”

Jodi Helmer is a North Carolina-based freelancer who covers the intersection between agriculture and business.

America’s industrial hemp industry exploded this year after federal legalization in 2018. As in any new industry, there is significant uncertainty and volatility in wholesale prices, making attempts to value the U.S. hemp market difficult. But after speaking with state officials and market participants across the country, Hemp Benchmarks was able to generate six months of price assessments for CBD-rich hemp biomass, several forms of extracted CBD and other hemp products.

We have also formulated estimates of the volume of 2019’s hemp crop, its potential market value and the amount and value of crude CBD oil that could be generated from it. However, the estimated value may not hold up against the dramatic supply increase expected after the harvest. Our data already shows significant price erosion for many hemp product categories even before harvest.

Hemp Benchmarks estimates that 2019’s harvest will produce between 98 and 122 million pounds of CBD-rich biomass suitable for extraction. We value that amount of product at between $2.1 billion and $2.7 billion, based on assumptions of an average CBD potency of 8% and a wholesale price of $2.72 / %CBD / pound, our average rate for biomass in September.

If prices erode, as many expect them to, the value of the biomass harvested this year will, of course, decrease. We already have observed biomass prices decline by 20% to 40% from April to September 2019, depending on transaction volume.

In producing CBD products, the first step is the extraction of crude CBD oil from hemp biomass. Based on our conversations with hemp processors, we estimate that between 1.96 and 2.44 million kilograms of crude CBD oil could be generated from the amount of biomass stated above. At September’s assessed price of $1,737 per pound, that amount of crude CBD oil would be worth between $3.4 billion and $4.2 billion.

Like biomass prices, rates for crude CBD oil have already eroded by large margins since we began reporting on it. September’s price for crude is down by 63% from April’s price of $4,661 per kilogram.

Crude CBD oil can then be used to generate refined hemp oil, which includes full-spectrum distillate and broad-spectrum (or THC-free) distillate, as well as CBD isolate. Prices for refined hemp oil and CBD isolate have also plummeted through the spring and summer months, with CBD isolate prices being hit the hardest.

Finally, there are questions as to whether the U.S. has sufficient infrastructure to dry and process the biomass from this year’s harvest. If not, it is possible that significant portions of the biomass could go to waste, reducing the potential value of the market, which would in turn cause contractions in the amount of CBD products that can be manufactured. This is all notwithstanding the downturn in wholesale prices that many market participants expect regardless.

Many are bullish on the industrial hemp and CBD markets, and not without reason. However, as our six months of assessing prices and reporting on the young U.S. hemp industry has shown, significant price erosion and a supply chain that is still under construction could seriously dent some of the sky-high market valuations that have been put forward.

Adam Koh is editorial director for Cannabis Benchmarks and Hemp Benchmarks.