Going Capillary on Cannabis By Joli A. Hohenstein

How are cultivators moving to easier, more economical watering for indoor growing?

With many cannabis production operations in non-traditional spaces such as warehouses, cultural guidelines can be constantly in flux. Even in greenhouse operations, cannabis cultivation requires the careful attention and detail that all indoor growing crops require. For many cultivators, capillary watering mats provide the ideal solution, offering more controlled watering and better efficiency even in the most unique environments.

“Cannabis is like most indoor crops,” says Justin DeAngelis, who has produced cannabis in many legal markets and is director of horticulture for Silver State Wellness and Las Vegas Releaf, with headquarters in Las Vegas and San Diego. “When it comes to irrigation systems, all system parameters must be identical, or it is impossible to irrigate each plant consistently. Capillary mats eliminate some of these standardization issues by allowing the least saturated plants to uptake the highest volume of water.”

While he has had experience using capillary mats for a dozen years or more in other crops before cannabis, DeAngelis says they’re still in the early adoption stage in the cannabis market, though it should be an easy transition.

JD Koontz, a cannabis cultivator and a process manufacturing consultant for Denver, Colorado-based Chartwell Group, has seen that for himself. In addition to consulting for cannabis cultivators in multiple states, he currently produces about 10,000 plants himself and has been a grower for approximately 25 years. He’s been using WaterPulse capillary mats to grow cannabis for about a year, and has used the capillary technology outside at nurseries for much longer.

“When you water from the top, it creates pore channels in the soil. Since with capillary mats the nutrients are at the bottom within the mat, it wicks the nutrients from there up the medium as needed,” he explains. “So the original water paths are now back filled with increased oxygenation, which leads to better root growth.”

Both cultivators say any grower familiar with large-scale production and automation who is watering scientifically rather than simply going by a predetermined frequency and volume will adapt well to capillary technology. Most existing plumbing and water delivery components are already in place and can be retrofitted to work with the capillary mats. “I know growers from 60 to 8,000 square feet that could use it easily,” Koontz says. “It’s especially beneficial for the vegetative rooms, when cannabis is in the vegetative state. For vegetative and for nursery in 1 gallon or 21⁄2 gallons, they work great.”

DeAngelis agrees. “Anyone who understands plant physiology and nutrient uptake will be fine,” he says. “More people aren’t using them simply because they are unaware of the product.”

Economic Efficiency

“Capillary mats operate with extremely high efficiency and come with an extremely low up-front cost when compared to other options chosen by cannabis gardeners,” DeAngelis says. “Low upfront cost is a huge benefit, especially during a company’s start-up phase when irrigation is traditionally purchased.”

Growers using capillary mats are seeing savings in water, fertilizer and labor, as they’re able to reduce and sometimes eliminate hand watering. “Capillary mats have allowed some growers to reduce their labor for hand watering by 80 percent or more,” says Scott Kegerreis, national sales manager for WaterPulse.

Added to that, they’re making watering more efficient. “When you grow indoors, you’re in a bit more controlled environment,” says Koontz. “Capillary mats move easily across all platforms, and you don’t have the huge pumps doing this work and wasting a lot of water and touches on the plants.”

With a manufacturing background, he stays well focused on driving down costs. Since installing capillary mats, Koontz has been able to use a small-scale pump with a small PSI output to meet irrigation needs, and accomplish the vertical water uptake needed. That makes a huge difference for him and his bottom line.

Technology Made Simple

“Capillary mats are relatively simple in terms of design and installation,” says DeAngelis. “The design process does not necessitate complicated irrigation volume or interval calculations as with other irrigation systems. It’s a simple installation and has very little learning curve.”

To get started, just roll out the mat, then water it down. Put the first pots on, making sure each is set on the map and not on the drip tape itself (to prevent compression that pinches off the line). Water the plant from the top once to define the holes that water. Then set the feeding to the mat instead of the plants. Slightly increase the pressure to the level you want. “It’s pretty brilliant,” says Koontz. “Really young plants won’t drink as much, and as they get really robust they drink more.”

Tweaking your frequency and amount is easy; the automated system allows watering any time of the day. Start by looking at water use of the crop and the plant size you’re watering, DeAngelis suggests. “There should be no difference from one plant cultivar to another, which is why capillary mats are used so often in traditional large scale greenhouse or outdoor production,” he says. “You’re going to have significant hot spots indoors, depending on how your HVAC is designed. Capillary mats provide the ability to mitigate some of these hot spot issues by providing more water to dryer plants and less water to more saturated plants — essentially regulating the water needs based on hot spots – and delivering a more even watering across the room as a whole.”

Another benefit: eliminating top-down watering of cannabis, which can result in compaction and added weight. “When you water from the bottom up, you’re providing oxygen through capillary action,” says DeAngelis. Plants are healthier and develop much stronger root systems, and watering from the bottom up helps reduce the opportunity for pest and foliage disease.

“The stronger root system has shown to provide higher yield situations for many crops,” Kegerreis says. Plants are watered more evenly, creating a more consistent crop finish that lets growers and business owners better forecast the yield they can anticipate from each crop.

In addition, capillary mats are reusable for an extended period of time, and easy to clean. “They’re great for sterilization and cleanliness,” says Koontz. “You pretty much blast and dry them and start over. It beats cleaning trays and some of the heavy labor out there. Plus you save money on a large irrigation system. We’re always looking for technology that makes our job easier and more automated, especially as we scale up.”

Joli A. Hohenstein

Joli A. Hohenstein is marketing and PR specialist for Pen & Petal, Inc., a marketing, advertising and public relations firm for the green industry.

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