Establishing an indoor cannabis growing facility comes with several hurdles and obstacles. With regulatory compliance, building permits, licensing, inspectors, and in a lot of cases, investment pressure, it is easy to overlook one of the most critical aspects of the entire process, irrigation. Water is essential for the plants’ growth, and it provides a direct avenue for nutrient injection. It seems obvious, but in most cases, irrigation is overlooked when it comes to planning and budgetary considerations.
Who to work with
A quick Google search lands you on several sites offering cannabis irrigation solutions, but it is crucial to qualify the companies you consider as potential partners. Look for companies and people with experience in design and installation. The Irrigation Association offers several certification programs for irrigation professionals. Look for these certifications when possible. If the person is providing any installation, make sure they hold have a valid contractor’s license. Irrigation is different than plumbing, electrical, or any other trade. You can purchase PVC pipe, pumps, and button emitters from just about anywhere. Putting those pieces together correctly is a different story.
The Water Source
Where is the source of water? Is it a domestic or ag well, or is it supplied from a municipality or city? And what is in the water? A complete water sample determines what equipment is needed, from reverse osmosis to de-chlorination systems. Knowing the flow and pressure, you have available from the source will help size the storage requirements and growing capacities. Remember, just because you have 80 psi does not mean you can irrigate a 30,000 square foot facility.
The Water Room
Space is a hot commodity for indoor growing. On almost every project we work on, the water room, tank room, fertigation room, irrigation room is always undersized. Consider the size and quantity of tanks, the size and amount number of nutrient tanks, and any necessary equipment that will be needed. This includes fertigation injection, reverse osmosis, and the required permeate and concentrate tanks, ozone or ultraviolet sterilization equipment, and any other equipment that needs to be housed in the water room.
Zones and Set Sizes
Knowing how you want to irrigate is critical. Suppose you will be growing several strains inside a room and want to irrigate one bench at a considerably different time than irrigating an entire room at one time. Whether you are using drip emitters, flood irrigation, sprinklers, or other types of irrigation methods, your irrigation design must incorporate the appropriate flow rate and required pressure. Pumping systems have operational limitations and targeting a lower flowrate will limit the maximum flow available and vice versa. If you are using a multi-tiered racking system and decide you want to irrigate a single level in a single room at a time, make sure you have enough time in the light cycle to do so. Know the flow will dictate pumping requirements and pipe sizing, and any considerations for the future should be made before installation.
Pipe sizing and layout should always be considered when it comes to your irrigation design. Under sizing, pipes can lead to unnecessary pressure loss and energy consumption. Also, consider the volume of water sitting in the pipelines. For an on-demand drip system that has short pulse irrigations, make sure to calculate travel times in pipelines to ensure proper nutrient injection. This is often not included in system designs, even from the most experienced designers. If you plan on having several nutrient recipe programs, consider running a single line to each room or zone or having multiple mainlines. With the technologies available today, we have designed, and installed systems with multiple recipes mainlines ran to each zone valve and can automate the process entirely.
As facilities continue to grow, and the space for irrigation design become more cluttered, remember to consider the basics. The irrigation design lays the foundation for fertigation, climate control, automation, drain water considerations, and the success of your growing operation at the end of the day.