Core values often get wrapped into buzzwords such as sustainability, locally sourced and organic. In the first part of a series of four articles exploring greenhouses and the environment, we’re going to take a look at indoor vs. outdoor farming in terms of resource management.
Full disclosure; I love the fact that I can eat fresh blueberries in February when my bushes outside are just sticks. Is there a better way to do it than trucking the berries from the farm to a distribution plant to the airport, where they’re flown from the airport to a distribution center, to the grocery store and finally to my kitchen table? That’s a lot of trucking and a lot of energy being wasted for my $3.99 pint of blueberries.The largest generation in the history of the country is demanding more locally grown, sustainable and organic food.
If those same blueberries were grown at a local greenhouse then trucked from the greenhouse directly to the grocery store, that would save diesel fuel and a lot of carbon emissions. People who can only afford to live near a highway, a port or an airport don’t need to ask a pulmonary specialist why their family has a higher rate of COPD than a family who lives on a cul-de-sac in the suburbs.
Fact: 55% of vegetables in the U.S. are grown under cover. The same energy saving principles apply to indoor cannabis and the reasons are consumer driven and producer driven. The largest generation in the history of the country is demanding more locally grown, sustainable and organic food. They want it for themselves and they want it for their kids.
The rapid proliferation of greenhouses over the past ten years is no coincidence. Millennials are forcing changes: organic fruit and vegetables now account for almost 15% of the produce market. A CNN poll last month revealed that 8 of 10 of registered Democrats listed climate change as a “very important” priority for presidential candidates. The issue is not party I.D.; the issue is that a large chunk of Americans are saying they’re worried about the direct and indirect impacts of climate change, such as increased flooding and wildfires.
So how does the consumer side tie into the cannabis industry? Consumers like doing business with companies who share their values. The hard part is balancing consumer values with investor values, which is why many indoor growers are turning to cultivation management platforms to help them satisfy both constituencies. They get the efficiency and they get to show their customers that they are good stewards of their environment. The goal is to catch things before it’s too late to save the plants. If you do that, you save the labor it costs to fix the problem, the labor and the expense of throwing away plants and you reduce pesticide and chemical usage. When that happens, your greenhouse makes more money and shows your customers you care about their values.
The indoor change is happening rapidly because people realize that technology is driving increased revenue while core consumer values are demanding less water waste, fewer pesticides, herbicides and fertilizers.Let’s add some more facts to the indoor-outdoor argument. According to an NCBI study of lettuce growing, “hydroponic lettuce production had an estimated water demand of 20 liters/kg, while conventional lettuce production had an estimated water demand of 250 liters/kg.” Even if the ratio is only 10:1, that’s a huge impact on a precious resource.
Looking at the pesticide issue, people often forget about the direct impact on people who farm. “Rates in the agricultural industry are the highest of any industrial sector and pesticide-related skin conditions represent between 15 and 25% of pesticide illness reports,” a 2016 article in The Journal of Cogent Medicine states. Given the recent reports about the chemicals in Roundup, do we even need to continue the conversation and talk about the effects of fertilizer?
I’ll finish up with a quote from a former grower. “The estimates I saw were in the range of between 25%-40% of produce being lost with outdoor farming while most greenhouse growers operate with a 10% loss ratio.”
The indoor change is happening rapidly because people realize that technology is driving increased revenue while core consumer values are demanding less water waste, fewer pesticides, herbicides and fertilizers. Lastly, most Americans simply have a moral aversion to seeing farms throw away food when so many other people are lined up at food banks.
No matter the size of your cannabis greenhouse operation, keeping your plants alive and healthy requires the best possible growing environment. This means greenhouse managers and personnel must frequently monitor the status of environmental conditions and equipment. The sooner someone discovers extreme temperature fluctuations, rising humidity or equipment failure, the more inventory you can save.
That’s why integrating a remote monitoring system into your greenhouse operation can save you time, money and anxiety. Monitoring systems that use cloud-based technology let you see real-time status of all monitored conditions and receive alerts right on your mobile device.
Installing a monitoring system and sensors can be easier than you might think. Here are answers to ten questions to ask before installing a cloud-based monitoring system:
What is required to use a remote monitoring system?
Most remote monitoring systems require an internet or WiFi connection and access to an electrical outlet. Programming is done through a website, so it’s easiest to use a computer for the initial setup. If you don’t have an internet connection at your location, you’ll want to choose a cellular system. Make sure that there’s sufficient signal strength at your site, and check the signal quality in the area before purchasing a cellular device.
2. How do we determine what kind of monitoring system and sensors we need?
A reputable manufacturer will have a well-trained support team that can assess your needs even without a site visit to determine which products are best for your application. If you feel you need them to check out your greenhouse operation,many companies can set up a video conference or FaceTime chat to substitute for being on site.
You will want to provide details about the scope and purpose of your cannabis growing operation. Important factors to discuss include:
Skeletal structure of the greenhouse (metal, plastic, wood, etc.) and the covering material (glass or plastic).
Floor space square footage and height of each of your greenhouses.
Number of greenhouse structures in your operation.
Outdoor climate to determine if you rely more on heating or air conditioning and the level of humidity control needed.
Space dedicated to phases of growth (cloning and propagation, vegetative, flowering) and the microclimates needed for each.
Types of lighting, ventilation and irrigation systems.
Level of technological automation versus manual operation in place.
The monitoring system representative will then determine the type of system that would best serve your operation, the number of base units you will need and the types of sensors required.
The representative should also be able to provide tips on the placement of the sensors you’re purchasing. For example, to ensure thorough air temperature coverage, place sensors throughout the greenhouse, next to the thermostat controlling the room temperature and in the center of the greenhouse out of direct sunlight.
Note that there shouldn’t be a cost for a demo, consultation or assistance throughout the sales process. Be sure to ask if there are any fees or licenses to keep using the monitoring equipment after you purchase it.
3. Are sensors included with the monitoring system?
In most cases, sensors are sold separately. The sensors you select depend upon the conditions you want to monitor and how many you can connect to your base unit. Certainly, temperature is critical, but there are many other factors to deal with as well, such as humidity, CO2, soil moisture, water pH, power and equipment failure, ventilation and physical security.
For example, humidity has a direct impact on the photosynthesis and transpiration of plants. High humidity can also cause disease and promote the growth of harmful mold, algae and mildew. Sensors can detect changes in humidity levels.
Like any other plant, cannabis needs CO2 to thrive, so it’s a good idea to include a CO2 sensor that will signal to the monitoring device when readings go out of the preset range. There are even sensors that you can place in the soil to measure moisture content to help prevent over- or underwatering, budget water usage costs, promote growth and increase crop yield and quality.
Of course, all the critical systems in your growing facility—from water pumps to irrigation lines to louvers—rely on electrical power. A power outage monitoring sensor detects power failure. It can also monitor equipment for conditions that predict if a problem is looming, such as power fluctuations that occur at specific times.
Ventilation systems not only help control temperature, they also provide fresh air that is critical to plant health. Automated systems include features like vented roofs, side vents and forced fans. Sensors placed on all these systems will send personnel an alert if they stop running or operate outside of preset parameters.
To monitor the physical security of your greenhouses, you can add sensors to entrance doors, windows, supply rooms and equipment sheds. During off hours, when no staff is on duty, you can remain vigilant and be alerted to any unauthorized entry into your facility.
4. Do monitoring systems only work with the manufacturer’s sensors?
Not necessarily. For example, certain monitoring units can connect with most 4-20mA sensors and transmitters regardless of the brand. When selecting sensors, you might have a choice between ones that are designed by the manufacturer to work specifically with the monitoring system or universal components made by a third party. If the components aren’t made by the system manufacturer, you’ll want to find out if they have been tested with the monitor you are choosing and if you need to work with another vendor to purchase the parts.
5. Is a monitoring system easy to set up, or do we need to hire an electrician?
Many monitoring systems are quick and easy to install, and users can often set them up without hiring an outside expert. Look for one that requires only a few simple physical installation steps. For example:
Mount the device to the wall or somewhere secure;
Plug it into an electrical outlet and an internet connection;
Connect the sensors.
You connect the sensors to the base unit’s terminal strip using wire, which is included with many sensors. The range of many wired sensors can be extended up to 2,000 feet away from the base unit by adding wire that can be easily purchased at any home store. It’s a good idea to hire an electrician if you need to run wires through walls or ceilings.
Usually, once you plug in the device and connect the sensors, you then create an account on the manufacturer’s designated website and begin using your device. There should be no fee to create an account and use the site.
If the manufacturer doesn’t offer installation services, ask if they can recommend a local representative in your area who can set up your system. If not, make sure they provide free technical support via phone or email to walk you through the installation and answer any questions you might have about programming and daily usage.
6. Is there a monthly fee to access all the functionality of a monitoring device?
Many web- or cloud-based systems provide free functionality with some limitations. You might have to purchase a premium subscription to unlock features such as text messaging, phone call alerts and unlimited data logging access.
7. Should we get a system that is wired or wireless? Will we need to have a phone line, cable, internet or something else?
Wireless can mean two different things as it relates to monitoring: how the system communicates its data to the outside world and how the sensors communicate with the system.
The most popular systems require an internet or WiFi connection, but if that’s not an option, cellular- and phone-based systems are available.
A hardwired monitoring system connects the sensors to the base device with wires. A wireless system uses built-in radio transmitters to communicate with the base unit. Some monitoring systems can accommodate a combination of hardwired and wireless sensors.
8. Can one system monitor several sensor inputs around the clock?
Once the monitoring system is installed and programmed, it will constantly read the information from the sensors 24/7. Cloud-based systems have data logging capabilities and store limitless amounts of information that you can view from any internet-connected device via a website or app.
If the system detects any sensor readings outside of the preset range, it will send an alarm to all designated personnel. The number of sensors a base unit can monitor varies. Make sure to evaluate your needs and to select one that can accommodate your present situation and future growth.
When a monitoring system identifies a change in status, it immediately sends alerts to people on your contact list. If you don’t want all your personnel to receive notifications at the same time, some devices can be programmed to send alerts in a tiered fashion or on a schedule. Multiple communications methods like phone, email and text provide extra assurance that you’ll get the alert. It’s a good idea to check the number of people the system can reach and if the system automatically cycles through the contact list until someone responds. Some systems allow for flexible scheduling, so that off-duty personnel don’t receive alerts.
9. Do monitoring systems have a back-up power system that will ensure the alarming function still works if the power goes out or if someone disconnects the power?
The safest choice is a cloud-based system that comes with a built-in battery backup that will last for hours in the event of a power failure. Cloud-based units constantly communicate a signal to the cloud to validate its online status. If the communication link is interrupted—for example by a power outage or an employee accidently switching off the unit—the system generates an alarm indicating that the internet connection is lost or that there is a cellular communications problem. Users are alerted about the disruption through phone, text or email. All data collected during this time will be stored in the device and will be uploaded to the cloud when the internet connection is restored.
If you opt for a cloud-based monitoring system, make sure the infrastructure used to create the cloud platform is monitored 24/7 by the manufacturer’s team. Ask if they have multiple backups across the country to ensure the system is never down.
10. What should we expect if we need technical support or repairs to the system?
Purchase your system from a reputable manufacturer that provides a warranty and offers full repair services in the event the product stops working as it should. Also, research to make sure their tech support team is knowledgeable and willing to walk you through any questions you have about your monitoring system. Often, support specialists can diagnose and correct unit setup and programming issues over the phone.
It helps to record your observations regarding the problem, so the tech team can look for trends and circumstances concerning the issue and better diagnose the problem. Ideally, the manufacturer can provide loaner units if your problem requires mailing the device to their facility for repair.
By Dr. Nadia Sabeh, Founder/President of Dr. Greenhouse
Controlling the environmental parameters of the indoor farm is essential to managing the productivity and health of your crop.
This presentation will discuss the critical roles that VPD, airflow, CO2, and other parameters play in the dynamic indoor environment, and we will review different systems and strategies you can use to manage them.
A project case study will be presented to demonstrate the costs associated with different climate management (HVAC) alternatives, including first cost, operating cost, maintenance, and crop productivity.
“Your tomatoes are organic. What about your weed?” The language on their homepage is clear: Consumers should seek the same high standards in their cannabis just as they do with food.
Earlier in the month, The Cannabis Certification Council (CCC), a nonprofit that promotes organic and fair trade practices in the cannabis industry, announced the launch of their #WhatsInMyWeed campaign. The consumer education initiative is designed to draw parallels between what buying choices people make in food and cannabis.
The consumer-facing idea is to produce videos and ads that make people question the ethics and environmental sustainability of their cannabis, just as they do when purchasing organic, fair trade-certified produce. According to Amy Andrle, owner of L’Eagle Services in Denver and board member with the CCC, the campaign should benefit cannabis companies that produce ethical and sustainable products. “This campaign is long overdue and much needed to alert consumers about the quality of their cannabis and begin to reward producers of organic, fair trade, sustainable and other high quality and integrity products just as they are in other consumer categories,” says Andrle. “We believe the campaign and accompanying website will drive demand and increase transparency in the cannabis industry.”
According to the press release, the website has a listing of cannabis certifications currently available now, information about them and where consumers can find certified products. Companies can sign up for the #WhatsInMyWeed Pledge as well to let consumers know they produce clean products.
The outside environment can vary widely depending on where your facility is located. However, the internal environment around any activity can have an effect on that activity and any personnel performing the activity, whether that’s storage, manufacturing, testing, office work, etc. These effects can, in turn, affect the product of such activities. Environmental control strategies aim to ensure that the environment supports efforts to keep product quality high in a manner that is economical and sensible, regardless of the outside weather conditions.
For this article, let us define the “environment” as characteristics related to the room air in which an activity is performed, setting aside construction and procedural conditions that may also affect the activity. Also, let us leave the issue of managing toxins or potent compounds for another time (as well as lighting, noise, vibration, air flow, differential pressures, etc). The intent here is to focus on the basics: temperature, humidity and a little bit on particulate counts.
Temperature and humidity are key because a non-suitable environment can result in the following problems:
Increased operator error
Difficulty in managing products (e.g. powders, capsules, etc)
Degradation of raw materials
Microbial and mold growth
USP <659> “Packaging and Storage Requirements” identifies room temperature as 20-25°C (68-77 °F) and is often used as a guideline for operations. If gowning is required, the temperature may be reduced to improve operator comfort. This is a good guide for human working areas. For areas that require other specific temperatures (e.g. refrigerated storage for raw materials), the temperature of the area should be set to those requirements.
Humidity can affect activities at the high end by allowing mold growth and at the low end by increasing static. Some products (or packaging materials) are hydroscopic, and will take on water from a humid environment. Working with particular products (e.g. powders) can also drive the requirement for better humidity control, since some powders become difficult to manage in either high or low humidity environments. For human operations without other constraints, a typical range for desirable humidity is in the range of 20 to 70% RH in manufacturing areas, allowing for occasional excursions above. As in the case of temperature, other requirements may dictate a different range.
In a typical work environment, it is often sufficient to control the temperature, while allowing the relative humidity to vary. If the humidity does not exceed the limits for the activity, then this approach is preferred, because controlling humidity adds a level of complexity (and cost) to the air handling. If humidity control is required, it can be managed by adding moisture via various humidification systems, or cooling/reheating air to remove moisture. When very low humidity is required, special equipment such as a desiccant system may be required. It should be noted that although you can save money by not implementing humidity control at the beginning, retrofitting your system for humidity control at a later time can be expensive and require a shutdown of the facility.
Good engineering practice can help prevent issues that may be caused by activities performed in inappropriately controlled environments. The following steps can help manage the process:
Plan your operations throughout your facility, taking into account the requirements for the temperature and humidity in each area and know what activities are most sensitive to the environment. Plans can change, so plan for contingencies whenever possible.
Write down your requirements in a User Requirement Specification (URS) to a level of detail that is sufficient for you to test against once the system is built. This should include specific temperature and RH ranges. You may have additional requirements. Don’t forget to include requirements for instrumentation that will allow you to monitor the temperature and RH of critical areas. This instrumentation should be calibrated.
Solicit and select proposals for work based on the URS that you have generated. The contractor will understand the weather in the area and can ensure that the system can meet your requirements. A good contractor can also further assist with other topics that are not within the scope of this article (particulates, differential pressures, managing heating or humidity generating equipment effects, etc).
Once work is completed, verify correct operation using the calibrated instrumentation provided, and make sure you add periodic calibration of critical equipment, as well as maintenance of your mechanical system(s), to your calibration and maintenance schedules, to keep everything running smoothly.
The main point is if you plan your facility and know your requirements, then you can avoid significant problems down the road as your company grows and activity in various areas increases. Chances are that a typical facility may not meet your particular requirements, and finding that out after you are operational can take away from your vacation time and peace of mind. Consider the environment, its good business!
Controlling your grow environment doesn’t start when you germinate your first seeds, it starts before you build your grow. There are steps you can take that will have a significant impact on mold growth and contamination, and these will vary based on the grow environment you choose.
Below is a roadmap to where each grow environment stands in terms of mold and contamination risk, and simple steps you can take to mitigate these factors.
The benefits of an outdoor grow are significant – using natural sunlight to grow plants is both inexpensive and environmentally sound. However, it allows the least amount of control and makes plants susceptible to weather conditions and outdoor contaminants including dust, wind, rain and insects. Depending on humidity and precipitation levels, mold can be a big issue as well.
When selecting an outdoor area for a cannabis farm, there are two important factors to consider: location and neighboring farmland. Geographical environments and sub-climates vary and once you have purchased land, you are committed, so be sure to consider these factors prior to purchase.
While arid desert climates have abundant sunlight and long growing seasons, flat, dry lands are subject to dust-storms, flash floods and exceedingly high winds that can damage crops. Conversely, more protected areas often have high humidity and rainfall late in the season, which can create huge issues with bud rot and mold. Neighboring farms also have an impact on your grow, so be sure to find out what they cultivate, what they spray, their harvest schedule and how they run their operation. Large farming equipment kicks up a lot of contaminant-laden dust and can damage crops by displacing insects to your farm if they harvest before you. Pesticide drift is also a major issue as even tiny amounts from a neighbor’s farm can cause your crops to fail testing, depending on what state you are in.
With outdoor grow environments always at the mercy of Mother Nature, any cultivator is wise to control contamination potential on the ground. Cover soil and protect your crop by planting cover crops and laying plastic mulch on as much ground as reasonable. In many cases it makes sense to irrigate uncultivated parts of your farm just to keep dust down.
Greenhouses are the future of cannabis cultivation. They allow growers to capture the full spectrum and power of the sun while lessening environmental impact and operating expenses, while still being able to precisely control the environment to grow great cannabis. With recent advancements in greenhouse technology such as automated control systems, positive pressure, geothermal heating or cooling and LED supplemental lighting, greenhouses are the future. However, older or economy greenhouses that take in unfiltered air from outside still have a medium amount of mold and contamination risk.
Before building your greenhouse, study the area while taking into account climate, weather conditions and sun exposure. Excessively windy areas can blow in contaminants, and extremely hot climates make cooling the greenhouse interior a challenging and costly endeavor.
There are several simple operational tactics to reduce contaminants in a greenhouse. Add a thrip screen to keep insects out, thoroughly clean pad walls with an oxidizing agent after each cycle, and keep plants at least 10 feet from pad walls. Plan to flip the entire greenhouse at once so that you can clean the greenhouse top to bottom before your next crop. A continuous harvest in your greenhouse allows contaminants to jump from one plant to the next and reduces the ability to control your environment and eliminate problems at the end of a cycle. Lastly, open shade curtains slowly in the morning. This prevents temperature inversion and condensation, which can cause water drops to fall from the ceiling and transfer contaminants onto plants below.
An indoor environment offers ultimate control to any grow operation. Cultivators can grow high-quality cannabis with the smallest potential for yeast and mold growth. Unfortunately, indoor environments are extremely expensive, inefficient and environmentally costly.
With indoor grow environments, keeping mold and contaminants at bay comes down to following a regimented plan that keeps all grow aspects clean and in order. To keep your grow environment clean, change HVAC filters multiple times a month. It’s also important to install HEPA filters and UV lights in HVAC systems to further reduce contamination threats. Clearly mark air returns if they are near the ground and keep those areas free of clutter. They are the lungs of your grow. Also, stop using brooms in the grow space. They stir up a lot of contaminants that have settled to the floor. Instead, use HEPA filter backpack vacuums or install a central vacuum system. Set up a “dirty room” for anything messy on a separate HVAC system, and be sure to thoroughly clean pots after every harvest cycle.
It is that time of year where the holidays afford us an opportunity for rest, recuperation and introspection. Becoming a new father to a healthy baby girl and having the privilege to make a living as a scientist, fills me with an immeasurable sense of appreciation and indebtedness. I’ve also been extremely fortunate this year to spend significant time with world-renowned cannabis experts, such as Christian West, Adam Jacques and Elton Prince, whom have shared with me a tremendous wealth of their knowledge about cannabis cultivation and the development of unique cannabis genetics. Neither of these gentlemen have formal scientific training in plant genetics; however, through decades of experimentation, observation and implementation, they’ve very elegantly used alchemy and the principles of Mendelian genetics to push the boundaries of cannabis genetics, ultimately modulating the expression of specific cannabinoids and terpenes. Hearing of their successes (and failures) has triggered significant wonderment and curiosity with respect to what can be done beyond the genetic level to keep pushing the equilibrium in this new frontier of medicine.
Lighting conditions can greatly impact the expression of terpenes (and cannabinoids) in cannabis.Of course genetics are the foundation for the production of premium cannabis. Without the proper genetic code, one cannot expect the cannabis plant to express the target constituents of interest. However, what happens when you have an elite genetic code, the holy grail of cannabis nucleotides if you will, and yet your plant does not produce the therapeutic compounds that you want and/or that are reflective of that elite genetic code? This ‘loss in translation’ can be explained by transcriptomics, and more specifically, epigenetics. In order for the genetic code (DNA) to be expressed as a gene product (RNA), it must be transcribed, a process that is modulated by epigenetic processes like DNA methylation and histone modification. In other words, the methylation of the genetic code can dictate whether or not a particular segment of DNA is transcribed into RNA, and ultimately expressed in the plant. To put this into context, if the DNA code for the enzyme THCA synthase is epigenetically silenced, then no THCA synthase is produced, your cannabis cannot convert CBGA into THCA, and now you have hemp that is devoid of THC.So what is the best lighting technology to enhance the expression of terpenes?
With all of that being said, how do we ensure that our plants thrive under favorable epigenetic conditions? The answer is the environment; and the expression of terpenes is an ideal indicator of favorable environmental conditions. While amazing anti-inflammatories, anti-oxidants and metabolic regulators for humans, terpenes are also extremely powerful anti-microbial agents that act as a robust a line of defense for the plant against bacteria and pests. So, if the threat of microbes can induce the expression of terpenes, then what about other environmental factors? I am of the opinion that the combination of increased exposure to bacteria and natural sunlight enhances the expression of terpenes in outdoor-grown cannabis compared to indoor-grown cannabis. This is strictly my opinion based off of my own qualitative observations, but the point being is that lighting conditions can greatly impact the expression of terpenes (and cannabinoids) in cannabis.
So what is the best lighting technology to enhance the expression of terpenes? Do I use full spectrum lighting or specific frequencies? The answer to these questions is that we don’t fully know at this point. Thanks to the McCree curve we have a fundamental understanding of the various frequencies within the visible light spectrum (400-700nm) that are beneficial to plants, also known as Photosynthetically Active Radiation (PAR). However, little-to-no research has been conducted to determine the impacts that the rest of the electromagnetic spectrum (also categorized as ‘light’) may have on plants. As such, we do not know with 100% certainty what frequencies should be applied, and at what times in the growth cycle, to completely optimize terpene concentrations. This is not to disparage the lighting professionals out there that have significant expertise in this field; however, I’m calling for the execution of peer-reviewed experiments that would transcend the boundaries of company white papers and anecdotal claims. In my opinion, this lack of environmental data provides a real opportunity for the cannabis industry to initiate the required collaborations between cannabis geneticists, technology companies and environmental scientists. This is one field of research that I wish to pursue with tenacity and I also welcome other interested parties to join me in this data quest. Together we can better understand the environmental factors, such as lighting, that are acting as the molecular light switches at the interface of genetics and transcriptomics in cannabis.
Editor’s note: This article should serve as a foundation of knowledge for yeast and mold in cannabis. Beginning in January 2018, we will publish a series of articles focused entirely on yeast and mold, discussing topics such as TYMC testing, preventing yeast and mold in cultivation and treatment methods to reduce yeast and mold.
Cannabis stakeholders, including cultivators, extractors, brokers, distributors and consumers, have been active in the shadows for decades. With the legalization of recreational adult use in several states, and more on the way, safety of the distributed product is one of the main concerns for regulators and the public. Currently, Colorado1, Nevada and Canada2 require total yeast and mold count (TYMC) compliance testing to evaluate whether or not cannabis is safe for human consumption. As the cannabis industry matures, it is likely that TYMC or other stringent testing for yeast and mold will be adopted in the increasingly regulated medical and recreational markets.
The goal of this article is to provide general information on yeast and mold, and to explain why TYMC is an important indicator in determining cannabis safety.
Yeast & Mold
Yeast and mold are members of the fungi family. Fungus, widespread in nature, can be found in the air, water, soil, vegetation and in decaying matter. The types of fungus found in different geographic regions vary based upon humidity, soil and other environmental conditions. In general, fungi can grow in a wide range of pH environments and temperatures, and can survive in harsh conditions that bacteria cannot. They are not able to produce their own food like plants, and survive by breaking down material from their surroundings into nutrients. Mold cannot thrive in an environment with limited oxygen, while yeast is able to grow with or without oxygen. Most molds, if grown for a long enough period, can be detected visually, while yeast growth is usually detected by off-flavor and fermentation.
Due to their versatility, it is rare to find a place or surface that is naturally free of fungi or their spores. Damp conditions, poor air quality and darker areas are inviting environments for yeast and mold growth.
Cannabis plants are grown in both indoor and outdoor conditions. Plants grown outdoors are exposed to wider ranges and larger populations of fungal species compared to indoor plants. However, factors such as improper watering, the type of soil and fertilizer and poor air circulation can all increase the chance of mold growth in indoor environments. Moreover, secondary contamination is a prevalent risk from human handling during harvest and trimming for both indoor and outdoor-grown cannabis. If humidity and temperature levels of drying and curing rooms are not carefully controlled, the final product could also easily develop fungi or their growth by-product.
What is TYMC?
TYMC, or total yeast and mold count, is the number of colony forming units present per gram of product (CFU/g). A colony forming unit is the scientific means of counting and reporting the population of live bacteria or yeast and mold in a product. To determine the count, the cannabis sample is plated on a petri dish which is then incubated at a specific temperature for three to five days. During this time, the yeast and mold present will grow and reproduce. Each colony, which represents an individual or a group of yeast and mold, produces one spot on the petri dish. Each spot is considered one colony forming unit.
Why is TYMC Measured?
TYMC is an indicator of the overall cleanliness of the product’s life cycle: growing environment, processing conditions, material handling and storage facilities. Mold by itself is not considered “bad,” but having a high mold count, as measured by TYMC, is alarming and could be detrimental to both consumers and cultivators.
The vast majority of mold and yeast present in the environment are indeed harmless, and even useful to humans. Some fungi are used commercially in production of fermented food, industrial alcohol, biodegradation of waste material and the production of antibiotics and enzymes, such as penicillin and proteases. However, certain fungi cause food spoilage and the production of mycotoxin, a fungal growth by-product that is toxic to humans and animals. Humans absorb mycotoxins through inhalation, skin contact and ingestion. Unfortunately, mycotoxins are very stable and withstand both freezing and cooking temperatures. One way to reduce mycotoxin levels in a product is to have a low TYMC.
Yeast and mold have been found to be prevalent in cannabis in both current and previous case studies. In a 2017 UC Davis study, 20 marijuana samples obtained from Northern California dispensaries were found to contain several yeast and mold species, including Cryptococcus, Mucor, Aspergillus fumigatus, Aspergillus niger, and Aspergillus flavus.3 The same results were reported in 1983, when marijuana samples collected from 14 cannabis smokers were analyzed. All of the above mold species in the 2017 study were present in 13 out of 14 marijuana samples.4
Aspergillus species niger, flavus, and fumigatus are known for aflatoxin production, a type of dangerous mycotoxin that can be lethal.5 Once a patient smokes and/or ingests cannabis with mold, the toxins and/or spores can thrive inside the lungs and body.6, 7 There are documented fatalities and complications in immunocompromised patients smoking cannabis with mold, including patients with HIV and other autoimmune diseases, as well as the elderly.8, 9, 10, 11
For this reason, regulations exist to limit the allowable TYMC counts for purposes of protecting consumer safety. At the time of writing this article, the acceptable limit for TYMC in cannabis plant material in Colorado, Nevada and Canada is ≤10,000 CFU/g. Washington state requires a mycotoxin test.12 California is looking into testing for specific Aspergillus species as a part of their requirement. As the cannabis industry continues to grow and advance, it is likely that additional states will adopt some form of TYMC testing into their regulatory testing requirements.
Centre for Disease control and prevention. 2004 Outbreak of Aflatoxin Poisoning – Eastern and central provinces, Kenya, Jan – July 2004. Morbidity and mortality weekly report.. Sep 3, 2004: 53(34): 790-793
Cescon DW, Page AV, Richardson S, Moore MJ, Boerner S, Gold WL. 2008. Invasive pulmonary Aspergillosis associated with marijuana use in a man with colorectal cancer. Diagnosis in Oncology. 26(13): 2214-2215.
Szyper-Kravits M, Lang R, Manor Y, Lahav M. 2001 Early invasive pulmonary aspergillosis in a leukemia patient linked to aspergillus contaminated marijuana smoking. Leukemia Lymphoma 42(6): 1433 – 1437.
Verweii PE, Kerremans JJ, Voss A, F.G. Meis M. 2000. Fungal contamination of Tobacco and Marijuana. JAMA 2000 284(22): 2875.
Ruchlemer R, Amit-Kohn M, Raveh D, Hanus L. 2015. Inhaled medicinal cannabis and the immunocompromised patient. Support Care Cancer. 23(3):819-822.
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Hamadeh R, Ardehali A, Locksley RM, York MK. 1983. Fatal aspergillosis associated with smoking contaminated marijuana, in a marrow transplant recipient. Chest. 94(2): 432-433.
Maintaining an environment that supports cultivation and keeps plants healthy is not an easy task. In cannabis growing, there are a variety of factors that greenhouse managers and personnel must monitor to ensure that their plants are in a healthy environment that fosters growth and development. Temperature, humidity, lighting and CO2 levels are a few of the conditions that need to be tailored to each cannabis greenhouse operation. However, it can be difficult to constantly monitor the status of your equipment and the greenhouse environment, especially after hours or during the off-season.
A remote monitoring system that’s properly selected and installed can help greenhouse managers keep their cannabis plants healthy, multiply their yields and increase return on investment. This type of system also helps operators identify patterns and trends in environmental conditions and get insight into larger issues that can prevent problems before they arise.
Here are some tips on key conditions to monitor and what you need to consider when selecting a monitoring system for your cannabis greenhouse operation:
Temperature plays a crucial role in any cannabis grow operation. The climate in your greenhouse must be warm enough to nurture photosynthesis and the growth of cannabis plants. Setting the incorrect temperature will significantly impact the potential yield of the plant and the rate at which it develops. A temperature too low will slow the growth of the cannabis, but too hot can lead to heat stress for your plants. The ideal temperature for a standard greenhouse is between 70 and 80 degrees Fahrenheit. However, depending on the stage of plant and desired growth densities, the temperature of the greenhouse needs to be adjusted accordingly.
Humidity directly affects plant photosynthesis and transpiration, so controlling humidity is vital in greenhouse growing. The ideal relative humidity (RH) for cannabis growth is around 60%. A low humidity level can cause water to evaporate too quickly for photosynthesis, while a humidity level that is too high can cause poor growth and possible mold and fungal disease. Monitoring the moisture content in the air of your greenhouse will help the plants during the transpiration process, increasing absorption of nutrients and overall health of the cannabis.
Your cannabis may be getting an abundance of natural light during the summer months, but maintaining adequate sunlight during the winter months can be a challenge. As a solution to this, many greenhouse managers equip their facilities with additional lights to supplement natural light during off-seasons or off-hours. To achieve the best possible yield, a cannabis plant in the budding stage should receive twelve hours of light each day, while other stages could require additional lighting. For example, the growth stage could require your cannabis to be exposed to sunlight for up to eighteen hours a day.
Like any other plant, cannabis requires CO2 to breathe. Greenhouse managers must set and monitor the CO2 levels in their facility to make sure that there is an adequate amount for the plants to develop, grow and be healthy. The amount of carbon dioxide required for your cannabis depends of the size of the facility and the amount of light the plants are receiving. However, a standard grow area for cannabis can maintain a CO2 range from 1000 to 1500 parts per million (PPM). A level below that threshold can result in slower growth of the plants, while a level above would lead to unused and wasted CO2.
Irrigation and Soil Moisture
One way to ensure a good yield from your cannabis is to water it regularly and monitor your soil moisture. Overwatering your plants can have the same effect, if not worse, than letting the soil become too dry. Plants’ roots need oxygen to survive, unlike leaves that breathe CO2, and when the soil is waterlogged the roots can’t provide their function. The lack of oxygen interferes with the roots’ nutrient uptake and photosynthesis causing the cannabis plant to wilt. The exact moisture content of the soil depends on the size of your greenhouse, temperature and humidity. Whether you hand water or are using a drip irrigation system, being aware of your soil moisture is vital to the long-term health of your cannabis.
Your greenhouse environment should mimic the ideal conditions in which cannabis plants flourish. With an indoor facility, you have the ability to control air circulation by venting hot air out and blowing fresh air in. Creating a circulation of air inside your greenhouse will increase your cannabis plant’s growth speed and yield. Additionally, an exhaust system helps control the temperature and humidity, while also preventing the invasion of mold and pests that thrive in hot, stagnant air.
When growing something of value, like cannabis, there will always be a threat of intruders. Whether your greenhouse is in a populated area or around hungry wildlife, any intruder could be detrimental to your overall yields and profit. Remote monitoring systems can give you peace of mind and instantly alert you when there is an unwanted presence in your greenhouse.
Knowing all the possible threats to your cannabis greenhouse helps you evaluate your specific needs, and ultimately identify the proper remote monitoring system.
Selecting the Right Monitoring System
Other factors to consider when choosing a monitoring system right for your operation include:
Base unit and sensors
Wireless or hardwired sensors
Communications to your site (Phone, cellular, Wi-Fi, etc.)
Programming and status checks
Return on investment
Base Units and Sensors
Each condition in your greenhouse that you want to monitor requires its own input on the base unit of the monitoring system. You must match your needs with the number of inputs available. A good fit for a smaller cannabis greenhouse may be a lower-cost, non-expandable monitoring system. However, larger facilities have many monitoring points and more people to alert when there’s a problem. If your cannabis operation is poised for growth, purchasing an expandable system could add value to the initial purchase because you wouldn’t have to replace your entire system in the future.
Your monitoring system should also have an internal rechargeable battery backup to ensure continuous monitoring and alerts in the event of a power outage. It is also recommended to have each base unit in a sheltered enclosure to protect it from moisture, dirt and other hazards.
Placement of sensors is also crucial. For example, temperature sensors in your greenhouse should be placed throughout the facility. They should be next to your thermostat and in the center of your greenhouse, preferably away from direct sunlight.
Wireless or Hardwired Sensors
Remote monitoring systems offer the option to have sensors hardwired directly to the base unit or sensors wirelessly connected. A hardwired monitoring system connects the sensors to the base device with wires. Generally, trenching long distances for wires is time consuming and costly. So alternatively, a wireless system uses built-in radio transmitters to communicate with the base unit. Some monitoring systems can accommodate a combination of hardwired and wireless sensors.
Communications to Your Site
Monitoring devices that use cellular communications must be registered on a wireless network (like Verizon or AT&T) before you can send or receive messages. Because cellular devices perform all communications over a wireless network, it is important that there be sufficient signal strength at the greenhouse. It is a good idea to check the signal quality in the area before purchasing a cellular product. If the cellular network has less than desirable coverage, it is possible to install an external antenna to help increase cellular signal.
When monitoring systems identify a change in status, they immediately send alerts to people on the contact list. If you don’t want all of your personnel to receive notifications at the same time, certain devices can be programmed to send alerts in a tiered fashion. It is important to consider the reach of the communications, so that you’ll be notified regardless of your locations. Multiple communications methods like phone, email and text provide extra assurance that you’ll get the alert. Also, note of the number of people the system can reach and if the system automatically cycles through the contact list until someone responds. Make sure the system allows for flexible scheduling so that it doesn’t send alarms to off-duty personnel.
Programming and Status Check
If you’re responsible for maintaining a commercial greenhouse facility, you want a system that will provide real-time status of all monitored conditions on demand. There are a few different ways to access your sensor readings. Options include calling to check status, viewing a web page, either on a local network or on the cloud, or accessing the information via an app on your mobile device. With a cloud-based system, the devices supervise themselves. This means if the internet or cellular connection goes down, the device will send an alarm to alert the appropriate personnel.
If you don’t select a cloud-based system, you will be limited to logging in through a local area network, which will allow you to make programming changes, access status conditions and review data logs. If internet connectivity is not available at your location, you will want to choose a cellular or phone system rather than Ethernet-based option.
Data history is valuable in identifying patterns and trends in your cannabis greenhouse conditions. Manually monitoring and recording environmental parameters takes a significant amount of personnel time and detracts from other important workplace demands. However, many monitoring systems automatically save information, recording tens of thousands of data points, dates and times. Cloud-based logging provides an unlimited number of records for users to view, graph, print and export data trends.
Analyzing data samples may lend insight to larger issues and prevent problems before they arise. For example, if the data log shows power fluctuations occurring at a regular time, it could be indicative of a more serious problem. Or, if the data shows signs of a ventilation fan or supplementary lighting beginning to malfunction, they can be repaired or replaced before total failure occurs.
Return On Investment
When deciding how much you should pay for a remote monitoring system, tally up the entire cost, fully installed with additional peripherals and sensors and any labor fees for installation. Then consider the value of your cannabis plant inventory and greenhouse equipment. Finally, factor in the cost of downtime, should an environmental event shut down your operation for a period of time.
Choosing the right greenhouse monitoring system and sensors could mean the difference between life and death for your cannabis plants. Understanding the conditions you need to watch and monitoring systems’ capabilities are they best way to protect your investment.
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