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Cannabis Grow Room Setup and Design: 9 Critical Considerations

Harvest Integrated


Speed and decisive execution are both important in the fast-paced cannabis industry. The faster you get to market, the better.

But careful preparation is just as important. 

Hurrying up and setting up the grow room as fast as possible is great, but it can also be a trap that disrupts your entire business. On the surface, it’s easy to think of grow room setup and design as fairly straightforward, however, there’s a lot to consider. Poor planning can end up costing you time, money, efficiency, quality and, ultimately, the success of your business. 

A comprehensive, well-thought-out grow room setup and design plan is essential. Yet, you need to keep in mind that different factors will have a different impact on the success of your grow room, with some factors having more bearing than others. The critical factors you need to consider when it comes to your indoor cannabis grow room setup and design are:

  1. Decontamination zones
  2. Air conditioning and dehumidification 
  3. Air and lighting
  4. CO2 control
  5. The quality of your real estate
  6. Capacity
  7. Location
  8. The crop
  9. Capital requirements

Let’s have a look at these nine factors in detail. 

1. Decontamination zones

Contamination, pests and diseases are the biggest causes of cannabis crop losses. Grow room decontamination areas are a must-have and they must be included in the grow room design. Failure to plan for proper decontamination zones will increase the risk of having diseases and pests entering the grow room and destroying your crop.  

2. Air conditioning and dehumidification

Failures and inconsistencies in environmental controls are the second biggest cause of crop loss in cannabis cultivation, after contamination, pests and plant disease. Unsurprisingly, a robust air conditioning and dehumidification system is vital for accurate environmental control in an indoor grow house.

When selecting a system, it’s important to consider temperature and humidity, two factors that are pivotal to consistency in the grow room. You should:

  • establish grow room humidity and temperature conditions set points; and 
  • understand the impact of these set points on your HVAC system. 

Doing this is of the utmost importance since uncontrolled temperature and humidity are ideal for odor, mold, pest infestation and disease. 

Thinking through your air conditioning and dehumidification is also vital because some systems just won’t work in grow rooms. While air conditioning and dehumidification can counteract grow room problems such as pests and mold, traditional HVAC systems aren’t specialized enough to keep up with the temperature and humidity changes in an indoor grow house and they use lots of energy. If you opt for such systems, you will likely have to invest in secondary equipment to take care of the extra load. Keeping in mind a system’s capabilities and limitations will help you avoid any issues once your grow room is operational.  

3. Air and lighting

The design of your grow room should ensure that you have a homogeneous environment, complete with well-mixed air and consistent air distribution. Poor ventilation design will result in microclimates that have a direct impact on your HVAC system’s performance. Poor airflow will make your space the perfect breeding ground for mold, pests and pathogens. 

Before setting up your grow facility, you need to carefully consider ventilation equipment size, air duct design, air sterilization and filtration, and the use of additional fans. All these elements will be critical to the success of your grow operation. Depending on your grow operation, you may need to incorporate fans to equalize conditions throughout the grow room and help evenly distribute air. You may need to prepare for how any future expansion will affect your environmental control system as well. In addition to this, you’ll have to plan for filtering and sterilizing incoming air to minimize the risk of contamination in the grow room. 

Similarly, you will need to decide which lighting technologies are worth pursuing, by looking at the benefits and drawbacks of each. For example, the vegetative growth phase doesn’t require intense light so you can save energy by using LEDs and only moving to HPS lights once the plants are in the flowering stage. 

Lighting choice will also determine the amount of heat that will be added to the grow room, thus helping establish the required HVAC system cooling capacity. For example, HPS lights tend to produce excess heat and so require more cooling. This is true for other options such as light-emitting ceramic (LEC) halide lights, although the latter can improve energy consumption. Designing and setting up a grow room without first considering this can produce improper HVAC capacity and control.

4. CO2  control

Adding carbon dioxide to grow rooms is common practice, and for good reason. It’s been found to increase plant growth. Nonetheless, if you are going to introduce carbon dioxide in your grow room, you need to do it right. 

You’ll need to know in advance any equipment you need for supplementing with carbon dioxide. For instance, since carbon dioxide addition is not recommended in the absence of light, your grow room setup may have to include light sensors that ensure that carbon dioxide enrichment doesn’t occur when the lights are off. 

Will you use carbon dioxide tanks or use outside air? If using tanks, you will need to have a safety plan that includes alarms and other safety devices. If using outside air, you will need to determine how the HVAC system will introduce the carbon dioxide to the grow room and what the extra load resulting from this setup means for the system’s performance. Furthermore, you’ll need to know how to evenly disperse the carbon dioxide throughout the grow room. Simply opening the valve on a gas tank and hoping for the best won’t work.

5. The quality of your real estate

The construction of your cannabis facility will have an impact on your grow operation. You need to choose one that works best for your business. 

Existing buildings may be difficult to convert into a cultivation facility. For instance, retrofitting may require costly structural repairs and the utilities (e.g. water and electricity) in an existing building may not be properly sized for cultivation. In the case of older buildings, you may have to deal with issues such as contaminants and poor insulation, which will require additional money and time to fix. 

New constructions can be more economical and efficient. Although they have to comply with current building codes, they often don’t have extra design requirements. New buildings also usually offer better insulation and vapor loads. This is especially important because it eliminates the need for larger HVAC systems, something that most older buildings with poor insulation require. 

But regardless of the construction you choose, you’ll have to think about future expansion. A small space will limit expansion, while a bigger space is more accommodating, allowing for a phased build-out. Choosing the construction is complex, hence it should always be one of the first considerations. The quality of your real estate will determine how much time, work and money end up going into setting up your grow room. 

6. Capacity

Grow room capacity will have a direct effect on your grow operation efficiency. Too often, growers overestimate the space they need, but this translates into unnecessary expenditure since the climate of the unused space has to be controlled as well. You need to consider the exact space you need when designing the grow room, taking into account all the extra space you need for people to move freely in the room. 

The required capacity is also important when it comes to grow room equipment. Using equipment that doesn’t correspond to the size of your grow room is a serious error that can be hard to recover from. Undersized equipment can cause humidity control issues. Oversized equipment tends to cycle on and off, resulting in equipment overuse and disruptive temperature and humidity fluctuations. Equipment must be properly sized and easy to repair. Moreover, it must include backup power and redundancy to ensure that the grow operation stays running even during a component failure. 

7. Location

Similar to grow room capacity, the location of your grow room will impact your efficiency. You may find a great building with the right size, but if it’s in a location without the right resources, it won’t do. A waste disposal system plus water and energy availability are some of the things you need to consider before deciding on a location. It won’t do you any good to enter into high-value real estate agreements only to discover that the location of your facility has limited or no resource availability.    

8. The crop

Ultimately, the whole point of setting up a good grow room is so you can grow the best crop. As such, you need to know your crop. Your equipment selection and size, as well as your quality and yield expectations, must match the specific crop variety you want to grow. 

For instance, the plant size will impact the cooling and dehumidification requirements of your chosen HVAC system. Smaller plants transpire less compared to big plants that have large moisture release. Additionally, plants at a certain growth stage need systems that meet the specific environmental conditions required at that stage. This means, for example, that an HVAC system designed for plants in the vegetative phase may not have the correct capacity to achieve the condition set points required by flowering plants.   

All these elements and more have to be considered during grow room design and set up so that your facility meets your plants’ needs. The following are some of the questions you need to answer during the design phase:

  • Will the grow room hold plants of all sizes?
  • Will we need to change the humidity and temperature set points as the plants go through the various growth stages?
  • What environmental controls are important for our crop variety?
  • What equipment is necessary to optimize the growth and yield of the chosen plant variety?

9. Capital requirements

This may seem obvious, but underestimating the required capital is a leading cause of business failure. Omitting certain costs during the design and setup phase can derail your operation right from the start, so you must ensure that your capital requirements include everything you need to set up a successful grow room. 

Things like extra installation costs and important add-ons (e.g. air filters and indoor air quality products) can be easy to overlook, together with quality. The lowest cost equipment and contractors may seem like a good idea until they cost you crop quality and grow room efficiency. Investing in the right people and products is the way to go. Granted, this can cost more upfront, but the good returns and business growth are worth it. 

Cannabis grow room setup: Doing it the right way

Indoor grow room setup and design require a lot of forethought. Changing many of the growing conditions after the grow room has been specified and built will be very costly, and maybe even impossible. Foresight, careful product selection, planning and getting the details right from the outset are absolutely essential for a successful grow operation.

Businesses have failed due to poorly set up grow rooms and systems – don’t be one of them. You can create a successful grow operation by collaborating with professionals who are knowledgeable about grow room setups and designs that work.