What’s the Difference? Hydroponics, Aquaponics & Aeroponics

Indoor cannabis cultivation breaks into two distinct categories, plants grown in soil and plants not grown in soil. With the rise of commercial (and even industrial) cannabis cultivation, soilless cultivation has become an increasingly effective method to precisely control the indoor environment.

There are three soilless growing technologies now used across the industry: hydroponics, aquaponics, and aeroponics. Hydroponics grows plants suspended in water, aeroponics grows plants suspended in air, and aquaponics is a unique combination of hydroponics and fish farming in an integrated system.

Hydroponics 101

Hydroponics is by far the most common soilless cultivation technique. It is the process of growing cannabis in a soilless substrate, suspended in nutrient-rich water.

There are several different hydroponic setup variations, including Ebb and Flow, Nutrient Film, Drip Systems, and Deep Water Culture. However, the basic premise starts with cannabis seedlings or clones in soilless substrates like Rockwool or clay pellets. Each plant sits in a grow net that is suspended within a reservoir. Water circulates through the system on a set schedule, delivering a specifically formulated nutrient solution.

Initially, growers adopted hydroponics for indoor cannabis cultivation because it delivered high yields in very small spaces. Long before legalization, it was one of the most discreet farming methods available. Soil-based systems typically require much more room for managing and mixing the soil, while the components of a hydroponic system remain tightly contained.

Hydroponics, like all soilless options, allows for precise control over the growing environment, which is why it’s so suitable for indoor cannabis cultivation. Compared with other standard farming methods (greenhouse, outdoor), hydroponics also requires significantly less labor to run.

But what about costs? A 2010 study comparing costs of a hydroponic, greenhouse, and conventional indoor operation estimated that the average price within a small hydroponic farm would be $225 per pound. Compared with greenhouse ($200-400) and indoor operations ($75-210), hydroponics is on par cost-wise.

Aquaponics 101

Aquaponics is an integration between two systems: fish farming and hydroponics. It is considered an efficient and environmentally friendly method of cannabis cultivation.

It begins with a fish farm. Farmers raise fish in tanks, and the fish waste goes through a multi-step process to remove solids. Bacteria and microbes transform the fish waste into a suitable nutrient-rich food for cannabis (or other) crops.

The crops—in this case, cannabis—grow hydroponically. They benefit from the nutrient-rich water while also performing a service for fish production. The plants filter and purify the water for reintroduction into the fish tanks. 

According to Green Relief, currently one of the only licensed cannabis aquaponics producers globally, their system uses 90 percent less water than traditional agriculture. They estimate they produce ten times higher yield per acre than soil-based farms.

A final benefit for aquaponics systems is the revenue from the fish. Green Relief donates thousands of pounds of tilapia raised within their system to local food banks, with a sizable $12 per fish tax write-off.

Aeroponics 101

Unlike hydroponics and aquaponics, aeroponics removes the need for a water reservoir. NASA has pioneered this technique in attempts to perfect farming in outer space.

Plants are still grown within a soilless substrate and nested in a grow net, but their roots dangle into an enclosed, light-sealed tank. Instead of filling or cycling a nutrient solution through the tank for the roots to pick up, there is a specially engineered spray system.

This system delivers a nutrient solution directly to the roots on a strict schedule. It’s everything the plants need to thrive, with little to no waste.

Like hydroponic systems, aeroponically grown plants tend to produce more roots than shoots, which means exceptionally robust root balls. The roots grown within these soilless systems evolve to reap the most from their growing medium and nutrient delivery method.

Although a few hobbyists are experimenting with aeroponics, it hasn’t become an industry standard for commercial operations. One of the few notable commercial aeroponics operations is Aeriz, located in Arizona. Aeriz cultivates within a closed-loop system, meaning almost everything gets recycled back into the production line.

The Differences Between Hydroponics, Aquaponics, and Aeroponics

In essence, hydroponics, aquaponics, and aeroponics are all riffs off the same soilless growing methodology. To date, hydroponics is the most common of the three. It’s readily used across the commercial cannabis sector and a feasible option for home growers.

Aquaponics, which combines fish farming and hydroponics into an enclosed system, is still getting off the ground. It’s more channeling to navigate regional regulations as it doesn’t fit nicely within either the fish farming or cannabis farming legislation.

Finally, aeroponics is the most technically advanced method of farming cannabis, but it offers complete control of the cultivation process when done right.

Is one more productive, environmentally friendly, or efficient than the others? Thus far, there has been little to no robust scientific assessment comparing each of these soilless systems.

When done right, growers can expect faster crop turnaround and often (although not always) better yields. As cannabis research begins to compare cultivation techniques, there is a need to assess these three systems' similarities and differences.