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March 21, 2023

The Science of Cultivating Cannabis: Tips for a Thriving Grow Operation

By Nathan Johnson, Ph.D.

Creating a healthy cannabis growing environment based on the science behind growing top-notch, medical-grade cannabis is essential for producing consistent results, assuming you start with quality genetics. Before speaking about the environment, it is necessary to highlight that quality and consistency has to first start with quality plant material. In this article, we will explore six key factors that make for a healthy cannabis growing environment and how regular testing allows growers to achieve consistency and quality. Keep in mind, optimizing these factors to the cannabis strains and environment they are grown in is a must.

Lighting

Lighting is the most important factor in creating a good cannabis growing environment. Cannabis plants require specific types, wavelength and exposure times to grow and produce high-quality flower. The two main types of light that are essential for cannabis growth are blue and red spectrum light where blue is primarily dedicated to vegetative growing and red for flowering. The exposure time is necessary for non-autoflower cannabis to maintain a vegetative or a flowering plant.

To ensure that the plants are receiving the right type and amount of light, growers can use specialized grow lights that provide both blue and red spectrum light. They can also monitor the intensity and duration of light using light meters and timers. Regular testing of the light spectrum and intensity can help growers fine-tune their lighting setup for optimal plant growth and flower development.

Temperature

Temperature always needs to be considered when creating a strong, healthy cannabis growing environment. Cannabis plants prefer a warm, humid environment, but temperatures that are too high or too low can negatively affect plant growth and flower development. The ideal temperature range for cannabis growth is between 70-85°F (21-29°C) during the day and between 58-70°F (14-21°C) at night.

To maintain a consistent temperature in the growing environment, growers can use temperature-controlled grow rooms or HVAC systems. They can also monitor the temperature using digital thermometers and adjust the temperature as needed. Regular testing of the temperature can help growers identify and address any temperature fluctuations that may affect plant growth and flower development.

Humidity

Like other factors that require precision, humidity needs to be carefully dialed in when creating an optimal cannabis growing environment. Cannabis plants prefer a humid environment, but too much humidity can promote the growth of mold and mildew. On the other hand, low humidity can cause the plants to dry out and become stressed.

To maintain a consistent humidity level, growers can use humidifiers and dehumidifiers in the growing environment. They can also monitor the humidity level using a hygrometer and adjust the humidity as needed. Regular testing of the humidity level can help growers identify and address any issues that may affect plant growth and flower development.

Airflow and Ventilation

Proper ventilation helps regulate temperature and humidity and prevents the buildup of carbon dioxide, which can be harmful to the plants. It also helps prevent the growth of mold and mildew. To ensure proper airflow and ventilation, growers can use fans and air ducts in the growing environment. They can also use carbon filters to remove odors and other contaminants from the air. Regular testing of the air quality can help growers identify and address any issues that may affect plant growth and flower development.

Nutrients

Nutrients are a non-negotiable for cannabis growth and flower development. Cannabis plants require a balanced supply of macronutrients such as nitrogen, phosphorus and potassium, as well as micronutrients such as calcium, magnesium and iron.

To ensure that the plants receive the right amount of nutrients, growers can use nutrient-rich soils or hydroponic systems. They can also supplement with fertilizers and other nutrients. Regular testing of the nutrient levels in the soil or growing medium can help growers adjust their nutrient regimen for optimal plant growth and flower development.

Pest and Disease Management

Cannabis plants are susceptible to over 90+ pests and diseases, including insects, mold, mildew, viruses and viroids commonly infected through the environment by touch, air, water and nutrients. The most common are spider mites, aphids, powdery mildew, botrytis, fusarium and hop latent viroid. It is estimated by the United Nations that 20% to 40% of total global crop loss is due to improper pest and disease management. The cannabis growing environment is no different.

Damage from whiteflies, thrips and powdery mildew could be prevented with an appropriate IPM

While lighting, humidity, air flow and nutrients are key aspects for a cannabis growth environment, the most common overlooked aspect of growing is proper pest and disease management. Cannabis plants are susceptible to a variety of pests and diseases, which can have a significant impact on plant health and crop yields. To take optimizing a cannabis growing environment one step further, here are five essentials for developing an effective pest and disease management setup.

Prevention

Prevention is the first and most important step in pest and disease management. Growers should always take steps to prevent pests and diseases from entering or infesting the growing environment in the first place. This can be done by quarantining new plants or clones, using clean equipment, sterilizing the growing area, and monitoring plants for signs of pests and diseases through both visual inspection as well as testing.

Some diseases such as those caused by viruses and viroids, require molecular based testing to identify. Growers should quarantine and test any new plants or clones before introducing them to the growing area. This can help prevent the spread of pests and diseases from infected plants to healthy ones. Growers can also use biological controls, such as beneficial insects, to help prevent pests from infesting the plants. These insects can help control pest populations by preying on them or interfering with their reproduction.

Early Detection

Early detection is key to preventing an entire crop from being infected and scrapped. Growers need to regularly inspect their plants for signs of pests and diseases, including yellowing leaves, discoloration, spots and unusual growth patterns. Early detection can help prevent the spread of pests and diseases and limit the damage they cause, not to mention saving a business’s bottom line!

Integrated Pest Management

Integrated Pest Management (IPM) is an approach to pest and disease management that involves a combination of preventative measures, biological controls and chemical treatments. IPM aims to reduce the use of chemical pesticides, which can be harmful to the environment and human health.

IPM involves regular monitoring of plants for signs of pests and diseases, using biological controls to prevent and control infestations, and only using chemical treatments as a last resort. Chemical treatments should be used sparingly and only when necessary, and growers should follow all safety precautions when using them.

Sanitation

Taking the necessary precautions to ensure all equipment used throughout a cultivation is properly sterilized will save growers from countless headaches. Growers should keep the growing area clean and free of debris, which can provide a breeding ground for pests and diseases. They should also regularly sterilize equipment and growing containers to prevent the spread of pathogens.

Record Keeping

Record keeping is essential for effective pest and disease management in the growing environment. Keep detailed records of all pest and disease issues, including the type of pest or disease, the severity of the infestation, and the treatments used. Cultivators, you will thank yourselves later! This will help identify recurring issues and develop effective pest and disease management strategies.

While there are key aspects of creating a healthy cannabis growing environment, the most common overlooked aspect of growing is on proper pest and disease management, which involves prevention, early detection, integrated pest management, sanitation, quarantine, and record keeping. By taking these steps, growers can help ensure the health and vitality of their plants, produce high-quality cannabis that consumers want and preserve their business’s bottom lines.

November 23, 2022

The 3-Legged Stool of Successful Grow Operations: Climate, Cultivation & Genetics – Part 3

By Phil Gibson

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This is Part 3 in The 3-Legged Stool of Successful Grow Operations series. Click here to see Part 1 and here to see Part 2. Stay tuned for Part 4, coming next week.

The Right Build Out

Aeroponic & hydroponic systems grow plants at a highly accelerated rate. A “clean room” type of construction approach is the best way to manage this type of grow operation. Starting with a facility that is completely void of any kind of wood or materials that are porous is a good start. Cellulose materials collect moisture and encourage mold and mildew formation no matter how good the sealant.

We have seen cultivation spaces built out of dry wall over wooden post construction and studs that look sealed and solid on the outside of walls but when repaired for plumbing or other expansion work, they are black inside and covered with nasty mold that no one wants near their grow space.

Panel construction over steel frames or steel studs with skins is a safer, more sterile approach than retrofitting a wooden structure. Panel construction offers the added benefit of rapid assembly and minimal labor costs. We have seen 300 light rooms assembled in a few days so it is both very cost effective and safely sealed for protected growth.

Room Sizes & Count

How do you best fill this space if you have a clean slate?

If you have unlimited space, temperature and humidity management should determine the room sizes in your facility. Room sizes that are square in dimensions tend to be easier to maintain from an environmental standpoint. Long narrow rooms are good for fan airflow but tend to be more expensive from a cooling and dehumidification point of view. The larger the room, the more likely that you will get “microclimates” within the room which can challenge yield optimization.

Now, of course, many grows are retrofits of existing structures so compromises can be necessary. We have found that cultivators that have both very large and mid-size rooms in the same facility (200 lights versus 70 lights) are consistently more successful in the 70 light rooms. These “smaller rooms (~1,500 ft2) out-yielded and out-performed the larger rooms using the same genetics and grow plans. Compartmentalization also minimizes the risk in the case that a calamity (i.e. pest infestation) strikes the room. In a large room scenario, the losses can damage your operation. For this reason, we recommend 70-100 light/tub rooms as a standard.

Rooms should also follow your nursery economics. Structuring your nursery to produce just enough clones/veg plants for your next flower room avoids wasted plant material and resources. Breaking a larger space down into individual rooms means that you need fewer veg plants to fill your flower room that week. The best way to optimize this is to have a number of rooms that are symmetrical with the number 8 (typical 8-week cycle genetics).

With 8 rooms running flower, you are able to plant one room per week for 8 weeks. In the 9^th week, you start over on room 1. This continuous harvest process is highly efficient from a labor standpoint and it minimizes the size of your mothers room (cost center). Additional space can be applied to your flower rooms. If you do not have infinite space, even divisors work just as well; 2 or 4 rooms can be planted in sequence for the same optimization (for 2-room structures, harvest and replant 1 room every 4 weeks for example). The optimal structure (8, 16, 24, or more rooms) enables you to optimize your profitability. If any of this needs further explanation, please just ask.

Not photoshopped: An “ideal” 70-tub flower room in a CEA greenhouse (courtesy of FarmaGrowers, South Africa)

Within your room choice, movable rows or columns of tubs/lights also provides optimal yields. Tubs/plants can be moved together for light usage efficiency and one 3-foot aisle can be opened for plant maintenance. Racking systems or movable trays/tubs make this convenient nowadays.

Floors

Concrete floors offer pockets for bacteria to collect and smolder. As such, they have to be sealed. Proper application of your sealant choice is required so that it does not peal up or crack after sealing. There are many benefits to sealed floors that is discussed in the white paper. Floor drains are the equivalent of a portal to Hell for a sterile grow operation. Avoid them at all costs.

Phased Construction

Tuning or optimizing you grow rooms for ideal flowering operation depends on your location. Our advice is that you build and optimize your facility in phases with the expectation that nothing is perfect and you will learn improvements in every phase of expansion. The immediate benefit is production that you can promote to your sales channels and revenue that starts as soon as possible to improve your profitability. This is also an excellent learning curve to apply to subsequent rooms. Our happiest customers are those that learned construction improvements in early rooms that were able to be applied to following rooms without headache. The ability to focus on one or two rooms also allows you to get the recipe correct rather than just relying on “winging it”.

Don’t Be In A Rush To Go Green

A 70-tub flower room (courtesy of FarmaGrowers, South Africa)

Validate your water supplies and their stability. Verify that the water in your aeroponic or hydroponic feeds that get to your plants are clean and sterile. This is much easier in a step-by-step fashion than in a crisis debug mode once production is in progress. Be very cautious about incoming clone supplies. We will talk about this more in the next chapter on Integrated Pest Management but incoming clones are a top pest vector that can contaminate your entire facility.

Warehouse Versus Greenhouse Cultivation Spaces

As we started out, controlling your environment is your most important concern. We have seen success in both indoor rooms and greenhouses. The defining success factor is controlling humidity and temperature. Modern sealed controlled environment (CEA) greenhouses do this well and CEA is somewhat of a given for indoor grows. More details on this in the white paper.

Packaging these recommendations gets you to the perfect body for your Formula 1 race car. Now, you are ready to look at some of the mechanics of protecting your operation from pesky little critters and biologicals that can derail your operation and weaken your engine.

Before we sign off this week, I wanted to highlight the ultimate build-out that we have seen so far. Of course, there are many challengers that have done this well but at this point, FarmaGrowers in South Africa has the best thought out facility we have seen. They acquired Good Manufacturing Practice (GMP) & Good Agricultural & Collection Practice (GACP) certification early in their operations due to very well-thought-out designs. They are exporting to global markets without irradiation today. Certainly, many successful customers have beautifully thought-out operations and there are several upcoming facilities that offer amazing planning that will challenge for this crown, but for now. FarmaGrowers leads the pack in this aspect. See here for a walkthrough.

To download the complete guide and get to the beef quickly, please request the complete white paper Top Quality Cultivation Facilities here.

Stay tuned for Part 4 coming next week where we’ll discuss Integrated Pest Management.

October 31, 2022

The 3-Legged Stool of Successful Grow Operations: Climate, Cultivation & Genetics – Part 1

By Chris Wrenn, Phil Gibson

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Ideal cannabis profits come from high demand/high selling prices and low production costs. The spread between those two, or margin, can determine the life or death of your business. We want to share this series of articles so that your next investment can be highly successful and high margin out-of-the-box.

Regardless of the grow method (soil, coco, rockwool, hydro or aero), every plant performs best in its own ideal environmental conditions. Experienced growers gained success through hard work, and just that, experience. Many have tried more advanced grow technologies, but shied away due to early trial failures or the complexity of maintaining chemistry across a grow facility. The wonderful thing now is that precision sensors and software controls eliminate the risk to robust healthy plants and harvest success. Growers are now able to both manage production while performing research in line with their operations.

We have learned a great deal working with our grow partners over the last 6 years. Every grow facility and location are different due to local weather, business environment and scale. This series of articles and guide, authored by our expert, Christopher Wrenn, will include recommendations of the most successful approaches we have seen here in North America and all over the world.

A 4-Layer fully aeroponic flower room using movable racking systems

Building top-quality cultivation facilities is no simple task. Cultivators are also looking for new help as they shift from older soil or media approaches to more efficient grow methods. One powerful method is aeroponics, which is very good at growing any type of plant in air in a sterile environment, with labor, nutrient and water savings.

Where possible, we will share key vendors that support healthy grow operations and (since it is World Series Time), customer examples that are knocking it out of the park. In today’s competitive business environment, it is critical to do what we can to increase profitability and survival in the face of steep headwinds. We want you to crush it and be “the last man standing.”

So, let’s get to it.

Climate: Environmental Control

We begin with a critical leg in your environment. The process of photosynthesis is more than just light, plant and moisture. We want to do more than just grow plants. We want to grow highly profitable plants. That means we have to accelerate photosynthesis so we are growing faster, bigger and more potent than our competitors.

The Vapor Pressure Deficit (VPD) is the amount of “drying power” available in the air surrounding your plants. This is a useful way to understand the amount of moisture your atmosphere can remove from your plants as they digest carbon dioxide and aspirate water and oxygen into the air around your plants. A higher vapor deficit is a good thing for growth; It is also a measurement of how much nutrient you can uptake into the plant roots and convert into size and potency in the canopy. We recommend that you have resources in your grow rooms to maintain your environment to within 5% of both your humidity and temperature targets for ideal results.

Onyx Agronomics is a Tier 3 indoor cultivator in the State of Washington. This is the canopy in one of their 8 flower rooms.

In our Top Quality Cultivation Facility white paper, we review environmental settings for temperature and humidity for mother, clone/veg and flower rooms for day and night light cycles from early cuttings through to end of harvest flush. Day temperatures can be up to 20% higher than night temperatures for example.

Cooling

Managing temperature may seem straight-forward but the heat generated by LED lights, HPS lights or the sun will vary across rooms, time exposure and with the distance of the light source from the plants. Measurement sensors should be distributed across rooms to monitor and trigger temperature resources.

Humidification/Dehumidification

This is a topic that can be underappreciated by cultivators. It is important to slowly transition humidity as you move plants from cuttings to clones, to veg and to flower. Beginning in a very humid stage to motivate root start, humidity will be stepped down from an opening near 90% down to an arid 50% in your end of flush flower rooms. We detail the transitions in 5% increments in the white paper.

The 4-Layer aeroponic flower room with movable racking systems from the side with a tall human for scale. One can do a lot with 30′ ceilings.

Relative Humidity (RH) and the related VPD are the key metrics to accelerating growth throughout the stages. Not sizing dehumidifiers correctly is one of the most common mistakes our grow partners learn about as they move to full production. In the first phase of turning cuttings from healthy mothers into rooted clones, hitting your target VPD to motivate root growth is the number one success factor. This will require the addition of humidity into your clone room. It is also typical to require raise the humidity of your flower rooms when you transition clone/veg plants from the high humidity clone/veg room into an initially dry flower room, otherwise the plants may go into shock as a result of the dramatic change.

As flowering begins, if humidity remains high, and the VPD is below target, the plants will not be moving nutrients and transpiring moisture. We have seen lowering the humidity from 70% in a flower room down to 50%, results in a yield increase from 50 grams to 90 grams of dry trim bud per plant, so a smooth transition can both accelerate growth and have a big impact on your margins and profitability.

Plants in aeroponics can truly have explosive growth. This means that they will also transpire moisture at an accelerated rate. Fast automated growth in aeroponics means increased humidity output. Sizing these critical systems for humidification/dehumidification are a critical part of the design process.

Airflow

Fans combined with your cooling/heating/humidity/dehu systems need to mix the air in a room to break the boundary layer at the leaf surface for transpiration. As we covered, VPD is critical to growth success. A dry surface motivates the plants to transpire moisture. We recommend flow rates across the canopy in a 0.5-1.5 meter/second rate to align to your genetics and where you are in the flowering process.

A raw facility before it gets outfitted.

Airflow and flowering means rich beautiful aromas are generated. Every facility has to consider odor control. If you are in a populated area, you will have ordinances and neighbors to satisfy. The best way to do this is to minimize the amount of air that exits a facility. This is also the cheapest approach.

Sterile HEPA filters and scrubbing systems clean air of pathogens and odor but they also need to circulate and “condition” air to the correct temperature and humidity levels before it can be recirculated into a room. Oftentimes, this is a good place to also recapture humidity and reinject it into your pure water cleaning systems.

Key vendors to talk to about sizing air treatment systems are SURNA, Quest, Desert Aire and AGS. Each of these vendors have specialties and tend to be superior partners in different regions of the world. We would be happy to introduce you to excellent support resources for air management systems.

To download the complete guide and get to the beef quickly, please request the complete white paper Top Quality Cultivation Facilities here.

Click here to see Part 2 where we discuss water quality and management.

May 23, 2018

Environmental Monitoring and Greenhouse Controls

By Cannabis Industry Journal Staff

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Cannabis Cultivation Virtual Conference: Part 2

Environmental Monitoring and Greenhouse Controls

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.