Considerations for cannabis cultivation

By Mark Norris, Giantlight

If there is any doubt about the economic viability of cannabis as an agricultural commodity, the Cannabis Industry and ever-growing list of approved SAHPRA Licensed Facilities funded by both local and International Investors tells a very Positive story. It is clear the burgeoning industry’s value will continue to grow. 

Concurrently, the need for cultivation and manufacturing facilities will expand as more SAPHRA license applications get activated with companies wishing to cash in on the crop. To be successful, these owners need design engineers who can specify the complex infrastructure needed for a bountiful harvest.

Cannabis is typically grown in controlled environments, such as greenhouses and indoor cultivation facilities. Such controlled environment agriculture facilities make it easier to meet certain government regulatory requirements. When designed correctly, these facilities also provide many benefits related to quality control and production.

Most Indoor cannabis operations are vertically integrated facilities, with indoor cultivation, post-harvest processing, manufacturing, quality control and packaging functions under one roof. As cannabis legalization advances and drives market growth, there is little doubt that best practices for legal growth operations will continue to develop.

So, as a leading South African OEM in LED lighting design and local manufacture to the ‘Growing Game’, we have been exposed to the reality that there are many elements to this horticulture segment with many key focus subjects to understand and focus on to name but a few here below to build a picture in words. In the meantime, be sure to rely on your HVAC, plumbing, electric, and lighting vendors for the advice you need to make sure that your indoor grow room is safe and efficient.

The management and reduction of variables sees a tightly controlled environment of (temperature, humidity, light, water, nutrients, carbon dioxide and airflow) which leads to maximum yields and product quality. All of the above are equally important and play a role in the process of building a facility. To this effect, we are sharing our journey into the world of grow lighting;

Lights, Lights, Lights: Illuminating your options

Choosing the right grow light for your cannabis is among the most important decisions you’ll make. From looking after seedlings and clones working through vegetation phases to the ultimate Flowering cycle with our LED product combination designs ranging from 55 W through to 1000 W and more depending on your Light Level Requirements. We want you delivering superb yields.

Most importantly, don’t spend money on a grow light without getting Informed at first. A great ‘bargain’ may ultimately just be a waste of your hard-earned cash. 

A typical indoor grow room when planning your LED Lighting requirements

Indoor cannabis operations typically include four types of grow rooms, each with unique environmental conditions, grow light types and schedules, and plant densities. These rooms are typically referred to as mother, clone, vegetative (or veg), and flower. 

1. Mother room. This room contains large plants with the genetics desired for the production plants. The plants are typically used for six to eight months before being replaced. Mother rooms occupy a relatively small area in relationship to the other grow rooms, generally about 5 percent of the total cultivation space. Environmental conditions are typically 21 degrees to 29.5 Celsius and 40 percent to 55 percent relative humidity (RH). Grow lights are typically kept on for 18 or more hours each day. 
2. Clone room. Leaves from Mother plants are clipped and used to propagate new plants in small containers or trays on racks within the Clone room. After two to four weeks, the plants are transplanted to the Veg room. Clone rooms are roughly the same size as a mother room. Clone room conditions can vary based on grower preferences, but typically fall in the range of 15 to 26 degrees Celsius and 50 percent to 70 percent RH. Grow lights are on for 18 to 24 hours per day.
3. Veg room. Plants are placed in larger containers on stationary or moveable benches, generally with two tiers or levels, and spend about six weeks at this stage. On average, Veg rooms will require about 20 percent of the total facility cultivation area. The space temperature can range from 21 to 29.5 degrees Celsius and humidity from 50 percent to 65 percent RH. Grow lights are kept on for 18 hours per day.  
4. Flower room. Flower rooms take up about 70 percent of the total indoor grow area of a cannabis facility. This is the last stage of growth before harvest, lasting six to 10 weeks. Most Flower rooms use either stationary or moveable benches, and some higher production operations will have multiple tiers. Temperatures of 22.3 to 29.5 degrees Celsius and 45 percent to 60 percent RH are the typical environmental conditions, and lights are on for 12 hours each day.

Best grow room design advancements

So, what type of grow lighting is best? This is a decision that will depend on various factors, including the size of your growing area, the type of cannabis you’re growing, and last but not least, how much you can spend. If you require a light for seedlings and clones, or you happen to have a ‘micro grow in a very small space (Grow Tent), you are likely best off with a simple CFL light.

For slightly bigger grows, consider a decent LED light anywhere from 55 W-600 W. As there won’t be much heat from the light, you may be okay with a simple exhaust system and a fan. For medium to large growing operations, you can look into high-end LED fixtures, as opposed to traditional HID lights

Don’t just look at wattage — Power equivalents between types of lights

Now, be aware that a 200 W CFL isn’t the same as a 200 W light LED, and neither are the same as a 200W HID. The wattage only indicates how much power the fixture uses, not saying anything about the light output. Because lighting technologies differ in their efficiency, you can’t compare them based on their wattage alone.

This also means that a LED fixture stated as being 600 W doesn’t necessarily emit the same amount of light (and therefore produce the same yields) as, say, a 600 W HID light. Honestly, the only way to determine true light output is to go over the specs from the manufacturer. Better yet, ask other growers for their experiences with a particular make or type of light – that way you’ll know what to expect

With the 4 key stages and zones identified to consider – we now need to plan to ‘light up’ a cannabis farm

Oh, that’s easy I remember thinking to myself – Plants, lights, action and cannabis is grown! How hard can it be to make a cannabis grow? Here is how the understanding process was ‘unpacked’.

When you set up an indoor or greenhouse cannabis grow room, counting on daylight is unreasonable. However, cannabis is a plant just like others, so it needs considerable quantities of light to grow, develop, and mature. Light is a vital component of cannabis’s photosynthesis, and you as a grower need to take proper care of providing sufficient light to your plants.

As a rule, cannabis growers have been using high-intensity discharge (HID) lights for their grow rooms but buying the whole set of lights even for a small plantation is just Too costly for a Plantsman. Thus, LED lights have gradually gained traction in the cannabis growing business, as they combine affordability with the correct number of lumens needed for growing cannabis properly.

If you want to grow cannabis with LED lights, look through our Horticulture Product Range to find everything you need for a safe, productive planting endeavour.

Benefits of LED light use

As we’ve just discussed, LED lights quickly won the hearts of small-scale growers because of their benefits compared to expensive HID lamps and the CFLs that were insufficient for the flowering phase. Here are the advantages of LED lights over other options:

• Affordability. A small LED light kit for a home garden will be much cheaper than a similar set of HID lamps.
• Cost-efficiency. A regular LED light consumes way less electricity than an HID lamp would. Thus, you will receive lower energy bills.
• Sustainability. Your LED lights will serve you much longer, with their average use time equalling 50,000 hours. To compare, a regular HID or CFL lamp lasts only around 20,000 hours.
• Water savings. Some HID lamps may be efficient, but they consume large amounts of energy and emit significant heat, thus causing cannabis plants to consume more water. LED lights are much gentler in terms efficient heat dissipation. So, they won’t dry your plants or substantially increase the temperature in the grow room.

Choosing the equipment

Now that you’ve decided to use LED lights in your grow room, you might be wondering, “what are the best LED grow lights for cannabis?” In most cases, it’s about choosing the correct PPFD levels required and a Reputable OEM brand providing you products of both Quality and Performance in conjunction with a Properly Planned Design and layout. This way the LED lights Ultimate performance is achieved for you if properly chosen and set up to specifications.

• If you’re a micro-grower with 1-2 plants to care for, your LED grow light shouldn’t really exceed 25 W.
• If you have a grow room of about three by three feet (suitable for four plants), it’s necessary to give them around 100 W of LED lights, increasing to 160 W by the flowering stage.

Ultimately, it’s necessary to choose the LED lights in accordance with their grow light spectrum measured in micromoles. Cannabis is on the higher end of the grow light need, so you will need around 800-1300 micromoles to grow your plants to their fullest potential

Setting up the LED Lights

Now it’s time to arrange the grow room equipped with LED lights. Here comes the most crucial issue – that of distancing your plants from one another and the lamps. How far should LED light be from cannabis plants? As a rule, lights below 300 watts should be positioned 30-70 cm away from the plants, while lamps with power exceeding 300 watts should be 70-80 cm above the plants. Still, leave some space for flexibility in the lamps’ positioning, as cannabis needs more LED light during the flowering stage. So, you will need to lower the lamps for the flowering period.

Conclusion

You can grow cannabis with LED lights like a pro with all these tips, maximizing your yield and reducing your garden’s dependence on daylight. Choose your LED lights carefully depending on your grow room’s size and the number of plants you have. Importantly, don’t forget to adjust the distance depending on your plants’ growth stage and monitor their response closely to avoid light burns and yield losses.

Further information

Q: How many LED watts per cannabis plant are needed for effective growth?

A: As a rule, the amount of LED wattage per cannabis plant depends on the distance of planting your garden. A rule of thumb is to provide 32 watts per square foot of your grow space. Thus, if you have an area of two-by-two feet, you need to provide at least 120 to 140 watts of LED light. If the grow area is two by four feet, the LED light wattage should range from 240 to 300 watts, and so on.

Q: When to put cannabis seedlings under LED light?

A: LED lights can be of value during the initial growing stage – that of seedlings. However, while you might be tempted to speed up seedlings' development with intense light, it's, in fact, harmful to the plants. Seedlings are too vulnerable, and too much LED light can burn them and dry the soil too much. Thus, it’s imperative to use subtle LED lights until the plants mature. Intense LED light will help only when the plants reach the vegetative stage of growth and development.

Common characteristics of all grow rooms include:

• Maintenance of the desired temperature and relative humidity for each stage of plant growth. Vapor pressure deficit (VPD) is pressure difference at the surface of the leaf and the vapor pressure of the surrounding air. VPD is a function of both temperature and relative humidity, and is a parameter that is closely monitored in most grow rooms. 
• Supplemental lighting, usually high-intensity discharge (high-pressure sodium or metal halide) or LED (Light Emitting Diodes).
• Growing medium or substrate. This can vary depending on grower preferences, type of product being developed and many other factors.
• Irrigation. Reverse osmosis water is typically generated and stored in tanks, then pumped through equipment that injects or mixes nutrients into the water. Fortified water, also known as “fertigation” water, is routed to each grow room. The fertigation control system is programmed to deliver a specific recipe to each stage of plant growth, based on a daily watering schedule. Watering rates will vary depending on the stage of the plant and other grower preferences. 

Some grow rooms are also enriched with carbon dioxide (CO₂), a key ingredient for plant photosynthesis. Bulk tanks or smaller portable cylinders provide the supply; CO₂ is delivered to each grow room directly or through the air-handling system for each room. The CO₂ concentration in flower rooms is typically maintained at three to four times the level found in the ambient
conditions.  

Other rooms and spaces in a typical vertically integrated cannabis operation include irrigation/water room, trim room, dry and cure rooms, extraction room, lab space, commercial kitchen, packaging areas, finished product warehousing/storage, waste handling/storage, shipping/receiving, offices, conference/training rooms, locker rooms, employee break rooms, utility rooms and general circulation.  

Facility design and infrastructure considerations

The design of a successful indoor cannabis grow facility requires careful consideration of many needs and characteristics unique to the product and the indoor growth environment.

The design of heating, ventilation, air conditioning and dehumidification (HVACD) systems is one of the most important aspects. Grow rooms require systems capable of managing variable sensible and latent loads. Systems and equipment can range from rudimentary and inefficient to highly sophisticated and energy efficient. 

Typically, air is recirculated 100 percent to prevent introduction of contaminants and to minimize CO₂ usage. Cooling and dehumidification are required year-round. HVACD equipment in grow facilities will face an almost continuous duty cycle. Distribution and mixing of airflow are critical to avoid stagnant areas and to prevent “micro-climates” from forming, which can lead to plant mold and diseases. Filtration and/or disinfection components are also important features of HVACD systems for grow rooms. 

Other important considerations include:

• Adequate water supply for the irrigation of plants, process cooling (if applicable), and fire protection.
• An energy source (natural gas, propane or electric) for general space heating, reheat for dehumidification and domestic water heating.
• Abundant vertical space in grow rooms for benches/racks, plant growth allowance, grow lights, HVACD equipment and ductwork, and fire protection sprinklers. 
• Irrigation/fertigation systems that include water treatment/purification equipment, nutrient injection or mixing equipment, storage tanks and automated controls. 
• Reclamation of excess fertigation water (known as “leachate”) or condensate collected from HVACD systems. Reclaimed water can be processed and reused for irrigation. Water recycling is required in some jurisdictions.   Integrated controls for each grow room that ideally integrate all functions into one platform – lighting, HVACD, CO₂and fertigation. 
• An insulated and well-sealed envelope of the grow rooms. Typical construction is a “box within a box,” with grow room walls/ceilings constructed of insulated metal panels (think of a walk-in cooler) inside a building structure. Nonporous, light-coloured and washable surfaces are preferred.  
• Emergency power systems and equipment redundancy. Some facilities elect to back up a portion of grow lighting and HVACD equipment. The typical goal is to maintain security and life-safety systems and keep plants alive for the duration of an outage or equipment failure. 
• Life-safety systems. The use of CO₂for enrichment of the plant environment requires monitoring and exhaust ventilation. Chemicals used on the manufacturing side of the facility may also require fume hoods or booths and emergency shower/eyewash stations.
• Building structural capacity to support mechanical equipment, grow lights, water piping (irrigation, chilled/heating water, fire protection, etc.).

Site-specific considerations

In the best-case scenario, a designer is consulted before an owner commits to a location for a cannabis grow facility. This helps ensure that important and basic requirements can be easily met by any site being considered — whether new construction or renovation of an existing building. These considerations include:

• Available space on the site for mechanical and electrical equipment;  
• Code and local government requirements;  
• Flexibility to accommodate future changes or facility expansion.  

Available energy is an extremely important consideration, as indoor cannabis facilities are energy-intensive operations. Any site being considered needs to have access to ample electrical power to operate grow lights and HVACD equipment. 

A power requirement of approximately 80 watts/square foot is not out of the question for cultivation areas, and a typical indoor grow facility may consume 900 kBTU/square foot of energy. (As a comparison, a typical hospital or laboratory may use much less, from 250 to 300 kBTU/square foot.) 

I have been involved in several projects where the owner had purchased a site or facility only to find out that the electric utility company cannot provide the required power without major system upgrades. This leads to schedule delays and additional costs for the owner.  

It’s also important to help owners understand that what they may perceive to be a minor change may have a large impact on a particular system. For example, operating a grow room at a different temperature or humidity setpoint, changing water rates, adding plants to a room, etc., may affect the performance of the HVACD system or negatively impact harvest yields or product quality. 

Once a proper site or building has been identified and chosen, speed-to-market becomes critical for owners. Securing project funding through typical means is still difficult in the cannabis industry, so most owners are required to raise funds through investors. 

The market is also highly competitive, so getting a product on the market first in a particular area is a big advantage. Therefore, designers and contractors should be prepared to assist the owner in getting their new facility up and running as quickly as possible through phased design and
construction. 

Indoor cultivation facilities involve very complex spaces that require a great deal of coordination between the grower and design and construction teams in order to position the operation for long-term success. 

A look at indoor cannabis grow room design

Like all plants, cannabis requires specific levels of nutrients, lighting, humidity, and air circulation to create an optimal growth environment. While these specifications may sound complicated, thanks to advancements in construction and other technologies, building a grow room is now far simpler than it has been in the past.

As cannabis goes mainstream, products and services have been pushed to market specifically for growing cannabis and hemp plants. Some of these innovations include:

Modular cannabis grow rooms

The pre-fabricated building industry provides everything from office spaces to locker rooms to classrooms. As such, it’s no surprise that some modular building companies are taking advantage of explosive growth in the cannabis sector. For growers who have the space for small additional structures, erecting a fully equipped pre-fab grow room can be a good option for getting started, or for a quick and easy expansion of an existing grow operation.

Greenhouses

Crop markets fluctuate, but the cannabis market is likely to grow for some time. For farmers or hobbyists with existing greenhouses, these facilities can be converted into suitable growth environments for cannabis plants. With proper Supplemental lighting, air circulation, temperature control, and other factors, a greenhouse can make a perfect hydroponic grow room for cannabis plants.

How to build a grow room in your garage, basement, and other existing rooms

For entrepreneurs seeking to break into the cannabis market, converting existing space into a grow room might be the most straightforward option. Basement grow room setups are often ideal because they maintain a similar temperature and moisture environment year-round, making them easier to control in terms of environmental factors. However, any number of spaces can be converted for successful use as grow rooms, including spare bedrooms, garages, sheds, walk-in closets, and grow tents.

Not everyone has room for additional structures on their property, but a range of services have popped up to help growers and potential growers convert unused spaces into effective cannabis grow rooms. For the uninitiated, seeking expert advice about LED Lighting, HVAC systems, plumbing, and building codes can avoid a lot future headaches. Aside from general cannabis consultants, individual lighting, HVAC, plumbing, electricity, and other vendors can also offer you quality advice about each portion of your legal indoor grow room set up.

How to create a controlled growth environment

Successfully controlling environmental factors is key to creating a successful indoor grow house. You’ll need to focus on the following factors to give your plants the best chance at growth:

Grow room dehumidifiers

Any growing plant experiences transpiration, which constantly transmits moisture into the air. Your HVAC system is crucial to controlling humidity and ensuring your plants don’t develop harmful mold or mildew that can kill them or make them unsalable.

When purchasing a grow room dehumidifier, consider the following: the amount of water plants get daily, the dehumidification rating of your temperature control system, and whether or not you’re using CO₂. Most plants transpire nearly all of the water they are given, so determining how much water you put in each day will help you determine how much you need your grown room dehumidifier to remove from the air each day.

Temperature control

Constant temperature control is crucial for cannabis growth. Plants will grow slowly if temperatures are too cool, but they can also suffer damage if grow room temperature is too high. Many indoor growers use air conditioners to control room temperatures and fans to provide air circulation that will keep lights from scorching plants. Depending on your geographic location, you may also need to insulate the room to maintain constant optimal temperatures.

Fresh air

Cannabis and hemp plants require fresh air to grow properly, so your HVAC system must be capable of constant air circulation. If the quality of your outdoor air is a concern, filters can be applied to ensure that the quality of air indoors remains high. If the smell of your grow room is an issue, carbon filters and ozone filters can also be applied to your exhaust system to help reduce the distinct odor emitted by healthy cannabis plants.

Plumbing

As a general rule of thumb, you’ll need a gallon of water per day for each pound of cannabis you are growing. As such, you’ll need an irrigation system for larger grow rooms or a spigot and hose that can reach your plants in a smaller operation. You’ll also need to install a floor drain and waterproof the walls and floor with tile or moisture-resistant drywall to ensure that you don’t develop rot or mold.

InDorSun

InDorSun is a proudly South African LED manufacturer whose founders originated from the solar and PV industry developing energy efficient solutions for a wide variety of industries. With manufacturing partner Giantlight, InDorSun have shone the light on cannabis horticultural lighting. Together the companies manufacture LED grow lights which produce full-spectrum light that replicates the colour of the sun.

www.indorsun.co.za

Giantlight

Giantlight is at the forefront of lighting technology – specifically solid state lighting and everything relating to LEDs and special effects. The company strives to remain the market leader in new and innovative lighting applications and continually brings new products to the market first. From design through manufacture and installation, Giantlight projects make a visual statement. Giantlight offers a comprehensive effect lighting solution.

www.giantlight.co.za