Cannabis cultivation facility design is a part of the planning process that is worthy of deep consideration. Some marijuana cultivation businesses have failed because of poorly considered layouts and workflow systems that are difficult to change once the site is set up. For example, having trimming rooms on a different level of the building than cultivation rooms can result in workers spending way too much time transporting newly harvested cannabis around the building, clogging up the stairwells and elevators, and turning workflow into a headache.
Another common facility design error is inadequate investment in environmental controls and air circulation. HVAC systems need to have redundancy, backup power, be cleanable outside plant rooms, and be easy to repair. They must be sized properly to do their share of dehumidifying and work in tandem with the dehumidification functions. Air circulation must be sufficient to keep all plants swaying in an artificial breeze, and also to keep the upper level of your flower canopy from getting too hot. The environmental controls, when done correctly, can cost between $75-$125 per square foot as a capital expense. The reason it’s worth the money is because failures and inconsistencies in environmental controls are the #2 cause of crop loss. (The #1 cause is acquiring pests from clones brought from other facilities.)
You might have noticed from reading cannabis cultivation magazines that many indoor marijuana cultivation spaces use subdivided rooms, somewhat like individual train cars, that typically measure about 20 ft across and 50-100 ft long. This approach has some good logic behind it. When the rooms are divided, they can have their own temperature controls, pest treatment practices, and they subdivide the workflow into digestible chunks, so one room can be set up, treated or harvested at a time. Also, when they are rectangular in shape, then circulation fans can blow evenly across plant canopies, where square rooms often have hot spots in the center, which is inevitably where mold and pest outbreaks first happen. If you need to use square rooms, make sure the airflow is engineered to handle the canopy evenly.
Being an R&D oriented cultivation consultant and educator, I also like divided rooms because they create a good foundation for controlled experiments. If, for example, you wanted to test the efficacy of a certain amount of Co2 injection, or a type of lighting system or nutrient regimen, doing this in one of your rooms, with another room containing the same strains but not variables, gives you reliable data on which to base system changes across the site.
A word of caution- ergonomics is often overlooked in commercial marijuana cultivation setups. It’s actually quite important, not only for the long-term health and happiness of the workers, but also to save money on labor costs (your greatest expense by far), and to make the treatment and testing of plants physically easy. Invariably, grow rooms get over-packed with plants, often with poor drainage management. In this case, peripheral plants always get neglected, and soil and runoff testing gets put on the back burner. Having all your plants on tables and all your tables on sliders or wheels helps mitigate this problem, and this design can also be very supportive of the pest treatment process, which is discussed in greater detail in the pest section listed at the bottom of this page.
One final word about the basics of design and setup is that you must take into account fire code regulations with regard to aisle widths, disabled access, emergency exits, frequency and spacing of egresses, trip hazards, and sprinkler systems. Check with an architect or your local Planning Department for regulations that are specific to your cannabis facility. To summarize, an ounce of prevention is worth a pound of cure; careful planning in your facility design process will save you huge headaches down the road.