As a licensed producer of medical cannabis, did you know that we grow using aquaponics?
We’ve created this page to break down what aquaponics is, how it works, and, more importantly, how it benefits you.

So, what is aquaponics?

Aquaponics is the combination of raising fish (aquaculture) and growing plants without soil (hydroponics) in a controlled, integrated system.
Aquaponics is a complex system with a variety of factors that take specialized, ongoing attention. In short, fish produce waste that helps plant growth, and the plants clean the water before it’s flushed back into fish tanks and the whole process repeats.
Here’s a simple breakdown of the nuts and bolts of an effective aquaponics system.

Fish Produce Waste

Any aquaponics system is built upon fish, since they produce the waste that’s converted into nutrients for the plants. The health of the fish ultimately determines the system’s success or failure.

Aquaponics systems vary in size, and the amount of fish needed varies as well. For example, a small home system could consist of one small tank with a few fish, whereas larger commercial aquaponics systems can have multiple large tanks with thousands of fish.
Regardless of system size, if the fish aren’t healthy then the entire system will fail. That’s why it’s so important to make sure the fish are happy.

Microbes Convert Waste into Plant Food

Also called nitrifying bacteria, microbes convert ammonia from the fish waste into nitrogen, which plants are able to absorb and use to grow.

This is a two-step process. First, these helpful bacteria eat the ammonia from fish waste and convert it into nitrite. But on its own, nitrite can be harmful to the fish. Much less so than ammonia, but it prevents the fish from absorbing oxygen.
Thankfully, other helpful bacteria convert these nitrites into nitrates, which are beneficial food that the plants can absorb and use to grow.
Solid fish waste is also turned into vermicompost and acts as additional food for the plants.

Plants Absorb Nutrients & Clean the Water

Now that helpful bacteria have turned the fish waste into plant food, the plants absorb all of these nutrients to grow.

While plants are the end product of an aquaponics system, they have a critical function in the entire system as well: purifying the water and allowing it to be sent back into the fish tanks.
Because the plants absorb all of the nitrates and carbon dioxide, this leaves just oxygen-rich water that’s able to be sent back into the fish tanks and start the process all over again.

Why is the re-use of water so important?

Since a closed-loop aquaponics system mimics how a natural ecosystem acts, water never needs to be flushed or discarded and the only water that’s added is to replace what’s lost from evaporation.
Why is this such a big deal?
In recirculating aquaculture (raising fish) alone, there are no plants to filter the water so fish waste builds up and releases nutrients into the water at a rapid rate. In order to keep the fish alive and healthy, the water must be flushed and replaced.
In conventional greenhouse or field growing systems, water is added to land where crops are grown (irrigation). These systems also require large amounts of water to replace what’s lost due to run-off and uptake from weeds, which aren’t normally found in an indoor growing system like aquaponics. Flushing water is even more crucial in greenhouses and fields because of a heavier reliance on fertilizers and pesticides.
Unfortunately, flushing and replacing water comes with significant environmental effects.
First, water has become an increasingly scarce resource around the world. According to a 2018 report from Wateraid, more than 60% of humanity lives in an area with water stress.
Cape Town, South Africa could soon become the first major city in the world to run out of water entirely. California has already experienced a severe drought and there are even places in Canada — yes, Canada — at risk of their own water crisis.
It’s essential that everyone uses as little water as possible, and that’s why we’re proud to be an aquaponics facility.
Second, flushing nutrient-rich water can lead to common but major environmental problems due to contamination of waterways and surrounding wetlands.
Run-off from greenhouses and other forms of agriculture using soil can contribute to the spread of soil-borne diseases into natural environments (i.e. spread of invasive species/pests) and be toxic to wildlife.

What kind of fish do we use in our aquaponics system?

Healthy fish are the foundation of aquaponics. While many types of fish can power a successful aquaponics setup, we use tilapia across our entire system.
Considered to be the oldest farmed fish in the world, tilapia are widely considered the best fish for aquaponics systems for three reasons:

  1. Tilapia grow quickly

We run one of the largest commercial aquaponics systems in Canada and, as a result, we need our fish to produce a lot of waste. Tilapia happen to be one of the fastest-growing fish breeds and eat a lot of food.
All of our tilapia are received as fingerlings that each weigh only a few grams, so our cannabis plant nursery is also a nursery for our fish. The faster our fish grow, the faster they can make an impact and contribute to our medical cannabis aquaponics system.

  1. Tilapia are easy to work with

Tilapia adapt to their conditions easily and can withstand temporary changes in water temperature or condition. They eat a lot, are incredibly resilient, and live full lives as well.

  1. Tilapia are edible

Tilapia has a nice, mild flavour so it’s adaptable to many different culinary styles. Since we feed our fish only organic fish feed, it’s a healthy a healthy food source.  
But we don’t eat our tilapia or make any money off of them. Once they reach market size, they’re picked up by a local food rescue service and delivered to local shelters to be prepared as meals.
To date,  Green Relief has donated more than 40,000 tilapia fish to feed those in need.