Cannabis - 46 Tips for Better Cultivation

As the cannabis industry grows up, the base of knowledge shared among large-scale cultivators is growing up, too. Cannabis Business Times interviewed a group of well-known industry players and frequent CBT contributors about their best practices, covering everything from lighting to custom fertilizing to specialized grow techniques, and design innovations, such as rolling aisles and vertical grows. They provide advice for beginner and advanced growers alike. Read on for tips, tricks and lessons gleaned from large-scale growing operations all over North America.

Brett Eaton

Director of Horticulture, American Cannabis Co. || Denver, Colorado

1. Think holistically when planning your operation

“Cultivators can maximize grow space by capturing both vertical and horizontal gain in cultivation rooms, having a well-planned layout for all equipment and functions of the operation, and streamlining workflow to eliminate unnecessary tasks.”

2. Hire experienced people

“Growing the highest-quality product is achieved by having a skilled staff that understands the smallest nuances in grow systems. Cultivators should understand, or hire a professional who understands, the design and build out of cultivation facilities, how to maintain proper environmental parameters, the cost/benefit analysis of all grow systems, implementation of clean protocols and workflow management.”

3. Test changes in small batches

“Many changes can have adverse effects if not implemented properly. For example, adding equipment without accounting for environmental parameters or power consumption can create problems. Also, a grower should never test new grow techniques on an entire crop — use a sample test crop instead. He or she should never implement new techniques without understanding any additional workflow or labor needed to make it successful.”

4. Don’t expect basement grow techniques to work on a large scale

Basement-growing techniques don’t translate to a large-scale cultivation facility. “Don’t hire unskilled labor, operate in a facility that can’t maintain a proper environment, operate without understanding production costs or begin operations without addressing an efficient building layout and future expansion.”

Scott Lowry

Chief Operations Officer, Global Organiks || Tecumseh, Ontario

5. More roots equals more fruits

“One common way to boost root growth is mycorrhizal inoculants, which utilize a symbiotic association between a fungus and the roots of the cannabis plant. The fungus stimulates root growth and increases the roots’ ability to take up nutrients from any media you choose (hydro, soil, coco fiber, and so on).”

6. Schedule foliar spraying

“A steady schedule of spraying cannabis plants with inoculants [pathogens/antigens] — with the lights off — will stimulate root growth and improve your plants’ node production.”

7. Implement low stress training

“Low stress training, or LST, is probably the safest, most risk-averse method to increasing top colas, the part of the plant on which buds grow together tightly. It involves bending unruly branches and using gardening wire or soft ties to hold the branches where you want them. A combination of topping, super-cropping, pruning and bending can achieve the goal of having several top colas to maximize yield.

“The majority of growers using LST are trying to keep their plants short and wide to take advantage of grow lights or the sun. Branches need to be bent down and secured away from other branches, creating a wider canopy with many colas from which the bud can grow.”

8. Super-crop your crop

“Super-cropping is not like pruning, where you actually snip off some of the plant. Instead, the basic crux of the super-cropping process is to bend (not break) branches near the top so the plant ‘thinks’ it doesn’t have tops. You’re essentially trying to increase the number of ‘tops’ by pushing the lower growth higher and wider, so that it, too, will flower.”

9. Start topping and FIMming

“These plant training techniques involve ‘pinching,’ or cutting off some of the plant’s top growth. They are a costless way to achieve better plant shape, which makes better use of available light, creates more colas and achieves bigger yields.” Many resources exist online that explain the intricacies of topping and FIMming.

10. Don’t cut your growth periods short

“Most growers know that the bigger the plant, the bigger the yield. So some growers maintain a veg cycle — the training period before flowering — of eight to 10 full weeks before transporting their multi-cola, multi-noded plant to the flowering room.”

11. Keep CO2 levels high

“Consistently high carbon dioxide levels — about 1,500 parts per million — can boost your yield by up to 30 percent if done correctly. The plants use the carbon dioxide to photosynthesize light into plant energy and sugars, which increases bud size and density.”

12. Focus on quality

Quality is far more important than maximizing yield if you are serious about your business and keeping your clients happy and loyal.

13. Stay on top of growing trends

“TLO, or True Living Organics style growing, and Veganics are truly next-level methods, though the grower sacrifices the massive yields of hydroponic growing for lower yields growing organically. There is always a tradeoff. There are also always better techniques coming out of grow circles around the world, so my advice is to keep yourselves in the know.”

14. Develop solid procedures now

“For the budding cannabis entrepreneur with a green thumb: The further you move up the chain, the more important process and procedure become. Keeping track of all changing variables — dates, times, sales, patient preferences — is what will help keep your business afloat. These variables provide key performance indicators that you can use to manage your day-to-day operations more effectively. And having a thick book of standard operating procedures for every process that goes on in your operation can truly be a lifesaver.”

“Consistently high carbon dioxide levels — about 1500 parts per million — can boost your yield by up to 30 percent if done correctly. The plants use the carbon dioxide to photosynthesize light into plant energy and sugars, which increases bud size and density.”

Stan Gorski

Gorski Grows, Owner || Columbus, Ohio

15. Build toward the canopy

“The top buds are going to get the most power, and the bottom are going to get the least, because they get the least amount of sun. But they’re still taking power away from the top buds. So what I do is, week 2 of bloom, or day 1 of week 3, after they’ve already done their 80 percent shoot and stretch, I go in and cut all those little bud sites, at least at the bottom. If I’ve got a 5-foot plant, then 1.5 feet of bottom growth gets cut out. Everything goes, except for if a branch reaches the top of the canopy. Then I’ll leave the branch, but take all the small buds.”

“There’s a lot of people that take the fan leaves off, but I have to leave them. Fan leaves are actually long-term food storage for the plant. So if the plant has deficiency and needs something, the first thing it does is pull from those. If I’m flushing, and those plants want something more, they’ll pull it right from the fan leaves first.”


16. Know your sources

“A huge thing I see is people getting online – which, I love the web, but you need to know what to believe and what not to believe. A lot of people take to the forums and they’ll get [things like], ‘so-and-so said this.’ Well, who is so-and-so? How much experience does he have? How many ... warehouses has he run? How many grows has he been a part of? How many successful grows has he done? Need a good resource? Jorge Cervantes, the [“Indoor Marijuana Horticulture: The Indoor Bible”]. Anything you want, it’s in there.”


17. Get to know your grow

“I tell smaller growers, find a strain you like, and find the phenotype of the strain you like, and learn to grow it and stick with it. A lot of growers will stick with a strain for 10 to 15 years. Keep moms, clone them.

“You’ll get consistency with single strains. Once you get it down, you’ll be able to tell the difference when it’s healthy and when it’s not. You will be able to tell if it needs more nitrogen or less potassium and phosphorous. You will be able to count on a certain amount of end product. Every grower loves a consistent strain. If you provide a consistent product, other people may come to rely on you for that for that specific phenotype. Once you can consistently produce great product from one phenotype, you can start looking at other strains. You will be able to compare characteristics that are similar or not so similar to what you’ve been growing. You will be able to identify problems more easily. And once you jump to something else, a different strain or different phenotype, adapting will be easier.”

Devin Liles

Vice President of Production, The Farm || Boulder, Colo.

18. Find a balance in your environment

“I would say the tendency is to maximize space and stuff as many plants as you can into the space you have. What a lot of people don’t understand is that has to be balanced with maintaining a really healthy environment for the plants, one that is less prone to pests and disease. The goal is to balance efficiency and the health and vigor of the crop overall: balancing adequate airflow, while at the same time maximizing the light you’re using as well as the space.

“One of my golden rules is that I want my growers to be able to put their eyes on every single plant on a regular basis. We have multiple operations and tens of thousands of square feet, but I want my guys to have an intimate relationship with every crop.

“I’ve seen some grows where they just stack a room, and they can’t get to the back corner, and unbeknownst to them, back in that dank corner they’ve allowed a microclimate that’s conducive to powdery mildew, for instance. And they get an outbreak, but they don’t know it until it’s spread to the front of the room, or they don’t know it because they don’t have that expertise to know scouting is a big part of integrated pest management.”

19. Look for more efficient technology

“It’s [already] becoming more and more known how much energy we consume. We need to do our best to work as efficiently as possible. Right now, we’re using the double-ended HPS bulbs, and what we’ve found is we can get more yield out of the same square footage with fewer of those lights than the older-technology HPS lights. It’s a better utilization of space, and we’re getting more weight per square foot with [fewer] lights.”

20. Make room for veg

“Make sure you have the adequate veg space for your plants. You have dedicated veg space, with different lighting, different HVAC, different environment vs. bloom spaces. Have enough veg space to get your plants ready and to the size that you want, such that you can turn over the bloom rooms really quickly. So when you harvest, you’re ready with the next crop to go in with as little downtime as possible. Some places I have more, but generally your veg space will be about a third the size of your overall bloom space.”

21. Plan for IPM

“I’m still amazed at how many people don’t understand a more comprehensive approach to pest and disease management. They just look to growing the plants, and they don’t understand that how you set everything up, how you manage your canopies, how and when you water all go into ensuring that you have healthy, robust plants, and that you’re not creating conditions for pest and disease to take hold. A lot of people are learning the hard way that you can’t just spray a toxic cure when a problem arises. It’s really about a more disciplined approach incorporating the fundamental principles of integrated pest management.”

Mel Frank

Industry veteran and cannabis author, publisher & consultant

22. Get innovative with your configuration

Spliffin, which sells vaporizing hardware, cannabinoid concentrates, and high-quality marijuana flowers, is having a grow room space designed inside a 200,000-square-foot facility. “The space will ultimately be divided into smaller rooms with 70 to 100 lamps each. The trademarked ‘Spacesaver’ design by Cannstruction features four sliding rows of plants. To improve use and durability, Cannstruction built grows to fit into two existing 19-foot by 30-foot rooms; each was filled with four rows of growing plants. Each row consists of three 4-foot by 8-foot trays and one 4-foot by 4-foot tray, forming a 4-foot by 28-foot row. The four rows rest on fixed beds with 20-inch spaces between beds. Each space can become an aisle as a row is moved.

“One 2-foot-wide crosswise space was created for room entry and access to each row. Each 20-inch lengthwise space between fixed beds could become an aisle. By sliding a row over to cover the aisle, a space opens a new aisle on the opposite side of the row that was moved. With four rows, five aisle positions can be created one at a time. The aisle can be on either side of the room or between any two rows, providing easy access to all plants.”

23. Automate watering and fertilizing with drain to recover waste

Each row in Spliffin’s room design “has a separate watering line and each pot has two drip emitters. More than 80 percent of the water [can be] recovered and recycled from start to harvest.”

24. Consider joined pipes instead of wheeled tables

“In what appears to be a long-lasting, maintenance-free design … the Spliffin facility design uses rows that roll on 1.25-inch joined pipes. They form 28-foot lengths laid atop solidly constructed beds affixed to the floor. The ease with which one person can move a 28-foot-long row proved surprising to me, a 71-year-old, 150-pound man.”

“Other growers try to treat their plants like bodybuilders by feeding them excessive amounts of fertilizers ... . What they do not understand is the point of diminishing returns. Once crossed, both yield and quality will suffer.”

Kenneth Morrow

Founder, Trichome Technologies || Northern California

25. If you’re thinking vertical, think beyond the math

“Business guys crunch the numbers on vertical growing, but they don’t necessarily understand the nuances of the plant. Humidity and temperature are critical. Unless you massively move the air in a building, it can be counterproductive to have too many shelves. You also may not get approval from OSHA.

“Growers usually have a limited amount of floor space, so you can see why someone might think to put in a mezzanine and double the floor space. But this just isn’t something that’s commonly used in large-scale agriculture. Nobody is working with vertical grows in crops like tomatoes and orchids. Sure, you can see what [Walt Disney World’s] Epcot is doing — they’ve got plants growing vertically, in moving rows, in every way possible. But in any commercial production facility you’re not going to find that.”

26. Beware overly complex vertical setups

“A few years ago, there were a few growers in Canada taking short clones and putting them into vertical aisles. I’ve also seen a grow with a setup that looked like a Ferris wheel. They had a circle that was 10 feet long [in circumference], but when you set it up in a circle, it [took up only] five feet. It rotated through irrigation and always got light from a light in the center. It was a very productive system.

“These may produce a good-quality product, but I don’t see them as efficient. A vertical grow can become, at the end of the day, more of a logistical nightmare. For a hobbyist or home grower it can work fine, but for the larger scale, if you’ve got $30 million at stake in your facility and you need to have forklifts moving things around and then equipment to decontaminate, the system itself can kill you with inefficiency.”

Brett & Keith Sprau

Head of Sales / Owner & Head Grower, Colorado Leaf LLC || Pueblo County, Colorado

27. Leverage your environment

“Colorado’s 300-plus days of sun helps us produce a consistent, high-quality, finished product. Our 150-acre farm is set at the foothills of the Wet Mountains, approximately 30 miles west of Pueblo, so the climate usually provides us with the best of both worlds, meaning the growing season of the Eastern Plains and the precipitation of the foothills.”

28. Consider all aspects of your location

“Our [location is also our] biggest challenge. We are 40 minutes from town and two hours from Denver, the biggest market for us. All of the resort towns are a minimum of three hours away. And our location has made it difficult to find reliable and consistent workers.”

29. Build strategically

“Every square inch in the greenhouse has a cost value to it, so we didn’t overbuild the veg house or underbuild the flower house. We used the newest aisle-eliminating rolling benches to cover the entire growing area and gained an extra 1,200 square feet of growing space per phase. We also planted a perpetual garden consisting of two veg, two flower and one clone room in order to maximize growing time and minimize down time. This leads to a harvest every four to six weeks.”

30. Consider supplemental LEDs and environmental controls

“Combining Colorado’s sun with our state-of-the-art supplemental LEDs has allowed us to maximize our yields while minimizing our cost per gram. In addition, we have been using an extremely advanced environmental controller with its own weather station to provide the ideal environment, which helps keep the consistent quality we demand as premiere retail wholesalers in this state.”

Leif B. Abel

Founder / Co-owner, Greatland Ganja || Kenai Peninsula, Alaska

31. Do not try to build and grow a hybrid system

“For example, hydro/organic. They are two types of dealing with the science of cultivating a plant, and mixing them usually results in trouble.”

32. Stick with what you know

“A tip another mentor gave me was this: Do what you know. So even though new techniques and knowledge should be pursued, the majority of the early crops should be a standard, known method the cultivator is comfortable with.”

Nic Easley & Adam Koh

Chief executive officer & chief cultivation officer 3C – Comprehensive Cannabis Consulting || Denver, Colorado

33. Control grow-room environments

“To maximize yield without compromising quality, indoor cultivators are well-served to install equipment that can exercise precise control over the room’s conditions. Both yield and quality will be lost if it is too humid or dry, too hot or cold, or if the environment has too much or too little carbon dioxide.

“We have seen facilities with mediocre strains, clueless staff and no effective direction from management still pulling very respectable yields simply because the environmental control equipment installed in the facility was top-notch and conditions in garden areas were optimal.”

34. Choose reliable, quality lighting

“Quality of light is possibly the single most important factor determining how well your plants will perform. Combined with disruptive technology, such as … reflector, chiller and dehumidifier systems — these are a game-changer for indoor growers. They significantly increase yield and quality while also becoming more efficient in terms of energy use.”

35. Buy a PAR meter

“New technology is being developed every day in the industry. If you choose to evaluate new lights or cooling technologies in your own grow, employ the proper equipment such as a photosynthetically active radiation (PAR) meter to accurately measure quality of light and an infrared thermometer, or “temperature gun,” to ensure your canopy is not too hot. These tools should be used in combination with your observations and data-collection protocols.”

36. Understand your inputs

“Many growers employ commercially produced fertilizer lines that come with ‘feed charts’ prescribing what to use, how much and when to feed. This is convenient, but it obscures understanding of the plants’ nutritional needs, which in commercial fertilizer lines are boiled down to products with catchy names.

“In many cases, the amounts prescribed by feed charts are higher than what is necessary. The educated grower who understands the roles of nitrogen, phosphorus, potassium and the various micronutrients required for plant growth — in addition to applying those nutrients in the proper amounts and with the right timing — can tweak pre-made feed charts to his or her great advantage.”

37. Consider vertical growing

“In vegetative areas, shelves or racks can be built such that smaller plants can be stacked on top of each other in multiple levels. For example, picture a room with 12-foot ceilings and numerous groups of new plantings that are less than a foot tall. Instead of simply hanging one fluorescent fixture over a 4-foot by 4-foot tray holding 75 new plantings, at least three levels could be fit into the same square footage of floor space, holding at least 225 plants rather than only 75.”

38. Consider wheeled tables

“Creative uses of space can allow a grower to stock a garden area almost completely full with plants under lights and no or minimal walkways. All he or she needs is tables on wheels, built to hold 4-foot by 4-foot trays of plants, and space sufficient to pull out the tables, a few at a time, to [allow space between to] work on the plants. Using this approach, staff will be able to give individualized attention to every plant in a room with only a minimal amount of workspace taking away from the space devoted to plants.”

39. Know your supply and storage needs

“Having a good grasp of logistics via detailed record-keeping and a tight, consistent production schedule can save space by minimizing the amount of necessary storage. Less storage space means more available room devoted to production. If you know how much soil you will need on a quarterly basis, you can order that amount and set re-order points so that you do not have to have copious amounts of supplies on hand.”

40. Pay attention to your particular micro-environment

“There are thousands of strains out there. It is important to remember that even strains with ostensibly the same genetics can grow very differently under different conditions. Never assume that a strain simply ‘is the way it is’ based on anecdotal evidence or even prior experience, especially if that experience has not been properly documented. Strains performing very well can sometimes be improved upon with focused attention and intelligent adjustments based on properly collected data.

“We have seen a top-quality strain that was testing at nearly 30-percent THC with great aroma and taste while smoking. It was yielding quite low, at or just below one pound per 1,000-watt lamp, but it blossomed into a strain from which I could consistently pull 2 pounds per light while keeping the same quality standards.

“This did not happen overnight. Over the course of more than a year the strain was run over a half-dozen times with alterations to lighting, fertilization, pest management approaches and other variables each run. After each adjustment, yield results and testing results were recorded in order to identify what benefited and what may hae suffered.”

41. Make flushing part of your routine

“To create a high-quality product, growers should irrigate their crop with unadulterated, properly pH-balanced reverse osmosis water for two weeks prior to harvest, at the very least. Three weeks can provide a very smooth smoking experience even with limited or no curing to the bud.”

42. Don’t neglect drying

“Many growers are so focused on the cultivation that the treatment of the buds afterward is neglected by comparison. You can be the best grower in the world, but if you do not properly dry and cure your product, it will turn out terribly. A climate-controlled space that can maintain proper drying conditions is essential. If possible, curing the dried buds in glass jars for at least a month will greatly improve the quality of your product.”

43. Remember: More doesn’t equal better

“Some indoor growers install more lights in a room simply because they have extra space. They think, ‘More lights = more weight,’ only to have those lights and additional plants spike the temperature and humidity in the room, leading to lower yields, powdery mildew and other problems.

“Other growers try to treat their plants like bodybuilders by feeding them excessive amounts of fertilizers, assuming that more nitrogen, phosphorus and potassium (NPK) will result in larger, denser buds. What they do not understand is the point of diminishing returns. Once crossed, both yield and quality will suffer.”

44. Don’t blindly fear pests

“Some growers treat their plants with pesticides, whether organic or chemical, legal or illegal, too frequently or in too-high concentrations. Rather than eliminating problems, this approach stresses your plants, making them more susceptible to pests. It is better to diagnose the pest pressuring your crop and treat the problem based on its life cycle and characteristics. For example, if mites reproduce every five days, treating plants every two days is likely overkill, causing more harm than good.”

45. Compartmentalize to prevent future pest issues

“If you are constructing a new facility, do not lay it out with only one or two very large areas for flowering plants. A number of these types of facilities exist in Denver and are sometimes referred to as ‘perpetual harvest’ rooms, as they are extremely large and groups of flowering plants at different stages of development share the same space. Plants are harvested and reset piecemeal, or incrementally.

“This may seem like an efficient use of space, but in this type of layout, a small pest issue can quickly turn into a problem that affects your entire grow. Compartmentalization may cut down on the amount of space devoted to production, but some division is necessary to ensure pest problems can be contained and minimized as much as possible.”

46. Don’t overcrowd your space

“In the desire to maximize productive grow space, we have seen grow rooms that are incredibly difficult to walk through, and certainly challenging for watering, pruning, spraying foliar nutrient supplementation or organic preventatives and other garden tasks. A grower may have ‘maximized’ the grow space, but the staff will break their backs to do basic tasks. Remember to retain enough space for staff to work comfortably and effectively so plants can be properly maintained.”