Indoor cannabis producers adopt water-efficiency systems in the heat of drought

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Drought has driven water restrictions across the West, impacting citizens, municipalities, farms and businesses – cannabis producers among them.

In response, many indoor producers have implemented water-efficiency technologies in past years to maintain enough water for their growing seasons while ensuring they are responsible stewards of the environment.

As the drought worsens, it’s likely more restrictions are coming, producers say.

Adopting long-term water-efficiency measures must be the answer to show leadership in an industry that – right or wrong – has had a reputation for water overuse.

“We’re building (production technologies) so we’re prepared, from both a fiduciary and a corporate responsibility standpoint, if there’s an issue with water use,” said Jigar Patel, co-founder and CEO of San Francisco’s NorCal Cannabis.

“But, more important, because we think it’s the right thing to do.”

Retention versus detention

Drought not only threatens water access but also impacts water quality, according to the U.S. Geological Survey and California Water Resources Control Board, which published a joint study this month reviewing 30 years of data from California’s agriculturally dense Central Valley.

Researchers found that because water in aquifers is accessed more often during drought, shallow groundwater – which is often contaminated by agricultural runoff – is pushed into the aquifers, and the cycle continues as drought intensifies.

To secure quality groundwater that can be cleaned and recycled, while mitigating dependence on groundwater, cannabis producers are increasingly using ag retention ponds.

It’s a practice common among greenhouse growers within the horticulture space.

According to a study on retention reservoirs released this week by Ohio State and Clemson universities, these resources are effective for:

  • Extending water resources.
  • Reducing adverse effects on the environment.
  • Capturing stormwater to water.
  • Reducing reliance on surface and groundwater.
  • Mitigating contaminants in water before discharge.

But, in some areas, laws restrict businesses from collecting rainwater.

And that forces growers to get creative.

“When we did our expansion of the greenhouse, our county no longer allowed retention ponds, so we had to change and rebuild our pond to be a detention pond,” said Aaron Van Wingerden, CEO of Dutch Heritage Gardens in Colorado Springs, Colorado, which produces hemp genetics and young plants and got its start in ornamental plants.

Dutch Heritage Gardens pumps water from an aquifer, then uses a detention pond to supplement its water supply. (A detention pond is different from a retention pond because it holds water only for a short period of time.)

The detention pond also helps to reduce peak storm flows and flooding and prevents runoff.

“Anything the plants don’t use, we have concrete and webbing of PVC into the concrete that diverts all the unused water into a series of concrete chambers,” Van Wingerden said. “We clean it and then recycle it and reuse it again.”

The system has increased water efficiency by 30%, he said.

“My well can only pump out, let’s say, 60 gallons per minute, and if I needed to drill a new well because I wasn’t recycling all of my water, you’re looking at about $500,000,” he added. “It’s very expensive, as opposed to recycling.”

Additionally, Dutch Heritage Gardens automated its irrigation systems, which includes ebb-and-flood floors that water plants from below.

“With ebb-and-flood floors … you’re adding at least $4 or $5 more per square foot greenhouse, but it gives you that freedom to push water back out into the bays and flood the floors,” Van Wingerden said.

Once flowering begins and buds start to get sticky with resin, the floors justify the investment by making watering more efficient and promoting healthier plants.

“We’re flooding floors for the last month or so of our cannabis life cycles for any smokable flower that we’re producing,” Van Wingerden said.

Advanced technology makes watering efficient

NorCal Cannabis, which operates six indoor cultivation facilities between Santa Rosa, California, and San Francisco, has invested in technology that reduces its water use by an average of 30%.

Netafim’s NUF runoff recycling system, a water and fertilizer filtration mechanism that cleans water and reduces pathogens, allows NorCal to reuse wasted water and any fertilizer present, which also helps decrease the company’s fertilizer use by 50%-70%, according to Patel.

But a technology under development in NorCal’s new 70,000-square-foot facility in Santa Rosa will drive the company’s water efficiency to another level, creating a closed loop by capturing the condensate from the operation’s dehumidifiers, Patel said.

“Between the two technologies, we believe we can get somewhere between 80% and 90% reuse of the water,” Patel told MJBizDaily.

When plants are irrigated, the system captures at least 30% of the runoff that comes off the plants, but the new technology also allows NorCal to capture the humidity that the plants transpire.

In addition to recapturing and reusing water, NorCal uses a crop-steering production platform called Aroya, which allows growers to create recipes and use sensor technology to better understand when the crops need water, Patel said.

“We’re able to understand what’s happening in the substrate of the plants,” he said.

“By doing so, you’re using the same amount of water you would normally use, but more efficiently for better production.”

Laura Drotleff can be reached at