“Salmon and trout could certainly be used in aquaponics systems with cannabis”

Green Relief is a Canadian medical cannabis company that uses aquaponics to grow marijuana using fish tanks and tilapia. But can it be done for salmon?

In October last year, the federal Cannabis Act came into effect making Canada the second country in the world (after Uruguay) to legalise the cultivation, possession, acquisition and consumption of cannabis and its by-products. Though one little-discussed advantage to the legislation was the ability to grow marijuana using aquaponics.

From its base in Hamilton, Ontario, Green Relief use a 30,000ft subterranean bunker to grow medical marijuana using aquaponics – blending aquaculture and hydroponics, without the need to discard water or add chemical fertilisers.

The filtered fish waste fertilises the cannabis plants, which in turn cleans the water for the fish. At the site, there is 6,000 tilapia and 4,500 plants at any given time. The fish are subsequently donated to homeless shelters

Unlikely marriage?
While fish and cannabis together sound like an unlikely marriage – Green Relief is not alone in using aquaponics. Last year, boutique salmon producer Salmon De France opened a farm that uses the same process to grow conventional vegetables and fruit.

US RAS pioneers Superior Fresh also put their Atlantics through the process. In fact, their Wisconsin facility – a 3-acre glass greenhouse where they grow various leafy greens and herbs – is the largest aquaponics facility in the world.

SalmonBusiness asked Green Relief Aquaponics Manager Melanie Pearson if salmon or trout could be on the cards for the company.

“This is a really interesting topic to cover using salmon and Aquaponics and more so, using salmon in Aquaponics with Cannabis. Two very profitable crops both in high demand! For this reason, integrating salmon into the aquaculture component of our systems and current operations is something that is certainly on our radar. We currently use tilapia in our systems but are planning to experiment with other species as we expand our operations,” she wrote in an email.

Pearson explained that in theory, salmon and trout could be used in aquaponics systems with cannabis but there were a few challenges.

“I feel confident that given the right feed, their waste would be able to provide all the nutrients that the cannabis plants would require for their growth. However, being that both species prefer cooler water temperatures, this poses a challenge for growing with plants (such as cannabis) that prefer slightly warmer conditions than what is optimal for these two fish species. A challenge that I feel deters many aquaponics growers from using salmon/trout in large-scale operations,” she added.

Own set of challenges
With a price fluctuating from CAD 6.99 to CAD 13 per gram, legal cannabis is more profitable than lettuce – which costs CAD 0.46 on average, so it makes economical sense to take advantage of the “Green Rush”.

“That being said, with the right system equipment and proper monitoring of environmental conditions, I definitely think it is something worth trying and if done properly, can be quite successful! Any combination of fish and plant species will come with its own set of challenges; however, these challenges can be tackled and overcome with experience and research,” Pearson concluded optimistically.