Question: My company is expanding and doubling its cultivation area. Currently, we hand water all of our stages of growth as we aim to stay as hands-on as possible, but it will not be fiscally responsible to continue this fertigation method, as it will also double our labor costs. What are your thoughts on automated fertigation systems and their effectiveness, efficiency, and accuracy?
Answer: A rule of thumb in traditional horticulture is that anything over 10,000 square feet of canopy requires an automated fertigation system – so it’s likely a great idea for your company to adopt automation.
A quality system should be dependable and efficient. However, there is much more to an accurate system than one may initially think – there are many ancillary components that make up an effective, efficient, and accurate irrigation fertigation system.
What follows are just some of the important components and aspects that make up that system.
- Ultraviolet water sterilizer: Sterilize all water sources utilized for irrigation (especially if using recycled water).
- Reverse osmosis water filtration: Placed in-line before the UV sterilizer to minimize filter clogging.
- Water heaters and water chillers: Incorporated when required to allow for a perfect water temperature.
- Drippers: Allow accurate water and nutrient flow rates.
- Nutrient/amendment injectors: Facilitate accurate macronutrient, micronutrient, and pH control.
- Nanobubble generator: Produce nanobubbles of oxygen that stay suspended longer, keeping water oxygenated and helping nutrient uptake and water sterilization (by oxidizing living organisms).
Besides the components and features listed above, there are other needed components, such as water pumps, feeder lines, and drip lines, all of which are subject to build-ups and clogging. Some growers utilize regular chemical shock treatments between crop cycles to sterilize systems when they are empty, especially when utilizing recycled water.
It is important to note that most organic nutrients and amendments cannot be utilized in drip irrigation systems as they encourage the proliferation of microfilm and buildups, which inevitably lead to rapid clogging of drip lines and drippers. Therefore, any organic amendments should still periodically be applied by hand, as desired.
A properly designed fertigation system also allows growers to precisely crop steer plants in a desired direction in a given growth stage, as well as tailor-blended nutrients and amendments for specific desired results.
There is a multitude of manufacturers and suppliers that provide all of the equipment needed to automate your fertigation system, but growers must thoroughly understand their requirements when designing and building a complex fertigation system; all equipment must be sized accordingly, and proper water pressures must be calculated prior to equipment purchase, as it will dictate the required pump size, filter sizes, and dripper size (calculated in gallons per hour), among other parts. There is no one-size-fits-all solution.
To properly design your system, you must create a design layout plan first to determine where each component is incorporated and the various needs that the layout will require. If this task is daunting or out of your realm, many reputable irrigation design companies can assist with planning and build-outs, with some offering turnkey fertigation solutions.
How you decide to set up and operate your new system will depend on the parameters you incorporate into it. As stated, every design is slightly different, so adjustments must be made to account for these nuances. For instance, your choice of growing media and container size will dictate many factors, such as dripper size. This makes it very important to plan and design for your specific parameters and requirements.
Kenneth Morrow is an award-winning grower and breeder. He is the owner of Trichome Technologies, a research and development company. He is also a consultant and author of the book "Marijuana Horticulture Fundamentals" and a founding advisory board member of Cannabis Business Times, where he has been a columnist since 2015. Find him on Instagram @trichometechnologies or reach him via email at: [email protected].
