How to Get the Best Results From Your Irrigation System

This article originally appeared in the August 2018 print issue of Cannabis Business Times. To subscribe, click here.

When it comes to water, growers should plan on having redundant systems, a 24/7- response service contract, storage for multiple days of normal operation—or all the above. Never running out of clean water is not just a goal, it is a key performance criterion. Here are eight steps to help make it possible.

1. Treat Your Water Properly

Determining how much treatment any source water requires begins with knowing what the water needs to be for good growth. Plants don’t need perfect water—not even potable (drinking) water—so the minimum requirements define the target production water.

The next step is to run lab tests to learn what is in your source water, including:

• levels of mineral content,
• alkalinity and pH,
• heavy metals,
• radiation and
• biologicals.

Comparing the test results to the target water levels allows the grower to see where levels are high and in need of treatment. Those treatments may include filtering, reverse osmosis (RO), ionic resin exchange columns, ozonation, acidification or UV light sterilization. Be sure that designs treat everything that needs to be treated and nothing more.

Water storage requires cleanliness. Water held for more than a couple of days should be monitored or treated with biocides such as chlorine bleach, hydrogen peroxide or ozonation to discourage biological growth. (Editor’s note: When using organic-based amendments, avoid using hydrogen peroxide, “as it will kill all beneficial bacteria and desired life forms in addition to pathogens,” writes Kenneth Morrow, owner of cannabis consultancy Trichome Technologies, in his book, “Marijuana Horticulture Fundamentals.”) Holding tanks need to be drained and cleaned with disinfectants on a regular schedule.

2. Utilize Smart Design

Water-system design is no secret, and information to help growers is plentiful from various sources. It involves a straightforward set of calculations that translate delivery requirements into a physical system.

Investors and managers should have high expectations of any water system—from cleanliness to a stable delivery rate over a prolonged period—and should deem the system operational and up to quality standards before formally accepting and paying for it.

Water-system suppliers should be contractually required to meet all specified water-delivery parameters.

3. Consider Safety

Safety first, safety always! Safe water-delivery systems start with backflow prevention where the water supply enters the facility. All pressurized water lines should be given the same respect as electricity—water lines can be subject to corrosion, leaks, clogs and freezing, among other problems, and should be frequently examined and well-maintained.

Water left on floors is a leading cause of falls in the horticulture workplace.

Tanks that employees must enter to clean require a two-person team, so no one gets trapped inside.

4. Create an Energy Plan

The cost of moving water depends on how much water must be delivered at any given time and how long the system must run. A system that delivers water to all rooms at once requires more pump capacity delivery to one room at a time. Likewise, a system that delivers all water in 15 minutes requires more pump capacity than a system that spreads water delivery across 12 hours.

To read the full article in Cannabis Business Times' August 2018 issue, click here.

Top photo by rgbspace | Adobe Stock