How to Grow Cannabis Aquaponically
Article written by
Homegrown Cannabis Co.American Seed Bank and Cultivation Experts
Content reviewed by
Dr. Lewis Jassey
Aquaponic growing is a cannabis cultivation technique that combines aquaculture and hydroponics. Plant roots are suspended in water and fed with fish waste, and you get fully organic buds.
How do you implement this innovative growing technique? Join us for a guide on aquaponics systems.
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What Is Aquaponic Growing?
Aquaponic systems are near-identical to hydroponics, the main difference being the food supply. Instead of dissolving fertilizer in water, you feed the fish and bacterial life in the aquarium, and they produce minerals for marijuana. For some people, having an aquarium combined with growing cannabis is an ideal combination that combines two hobbies!
At its simplest, this growing system consists of an aquarium and a tray with potted plants above it. A pump moves nutrient-rich water upward, and the runoff drifts downward.
Types of Aquaponic Cannabis Growing
Three main aquaponic setups differ in whether they use a medium and how the water moves. Let’s take a quick look.
Deep Water Culture Aquaponics
Deep water culture is a floating raft system consisting of foam boards in water. Net pots with plants sit on top of the aquarium, and roots float in the liquid.
Nutrient Film Technique Aquaponics
Nutrient film technique setups consist of pipes through which a thin film of fertilized water runs. Potted plants sit in holes above each tube, and the roots hang inside.
Media-Based Aquaponics
Media-based aquaponics is simpler to set up. It consists of a media bed with hydroton (an inert pH-neutral substrate) above an aquarium. The soil stabilizes the roots and lets you introduce a bloom-specific nutrient solution without polluting the tank.
Advantages and Disadvantages
Why pick or skip aquaponics? As is the case with any growing technique, growing using aquaponics has certain advantages and disadvantages.
Advantages
Aquaponic growing delivers the following advantages:
- Exceptional growth rates: This hydroponic system lets plant roots absorb high levels of nutrients and oxygen, causing rapid stretching.
- Sustainability: The setup uses one organism’s waste to feed another, reducing the need for artificial fertilizer.
- Low water usage: since liquid re-circulates, aquaponic production uses less water than soil cultivation.
- Better-flavored buds: The entirely natural ecosystem produces buds with sticky trichomes and a strong, smooth, natural aroma.
- Develops additional knowledge: Aquaponics has you learning a new skill set. You learn about fish biology, aquarium health, and cannabis cultivation. Great for hobbyists!
Disadvantages
Aquaponic farming brings the following challenges:
- Higher initial costs: Setting up a fish tank for cannabis cultivation is pricier than soil or regular hydroponics.
- High maintenance: Fish stocks require specific water temperatures, necessitating daily work to sustain functionality. You must look after and care for your fish just as you look after your plants.
- Trickier nutrient management: Organic fertilizer production is less precise, requiring more care to avoid mineral deficiencies.
Download Free Guide to Plant Nutrients
What You’ll Need to Get Started
If building it from scratch, a small-scale aquaponic set-up for indoor cultivation costs around $1400 and includes the following:
Fish Tank
A large acrylic tank is optimal. You can also use IBC cube tanks from food-grade plastics, as they’re affordable and very durable.
You need light for cannabis, but fish might get harmed by direct sunlight exposure. So, buy enough opaque cloth to wrap the tank.
Ammonia
Ammonia levels determine how much bacteria exists in the system. You can purchase supplements in stores or get full-blown aquarium kits.
Fish Species
Most people pick koi, trout, goldfish, tilapia, and catfish because they’re low-maintenance.
Pots and Media
A heavy-duty basket contains net pots filled with an inert medium like small rocks. If using a media-based set-up, you’ll also need burlap and soil.
Water Pump
A submersible pump circulates water to and from the root zone.
Filters
Filters remove solid waste from liquids sent to the roots. You may install a clarifier, vortex, or radial flow separator.
Best Strains for Aquaponic Cannabis
Most cultivars flourish in aquaponic gardens, but you’ll get the best results from strains that aren’t susceptible to nutrient issues.
Pick strains with robust roots and exceptional potential to stretch. Think Gorilla Glue #4 and Northern Lights: sturdy, mid-sized, and vigorous.
Setup
Here’s how to put the setup together and start growing in aquaponics.
Fish Tank and Fish
Cycle the aquarium with ammonia for a month to establish a large colony of beneficial bacteria. Install the pump while the system stabilizes, use an ammonia remover to eliminate the harmful chemicals from the water, and then introduce the fish.
Media Grow Bed
Install a large plastic tray on top of the aquarium and ensure it’s sturdy. Fill net pots with clay pebbles and line them up inside.
Those working with IBC tanks don’t even need an additional tray. You can cut off the top quarter of the tank, flip it inside down, and use it as a hydroponic table.
Since fish waste mainly produces nitrogen, you’ll manually add phosphorus and potassium to flowering-stage weed. Alternatively, create a dual root zone to divide the roots into two sections. The latter is submerged in water, while the upper sits in soil that you feed as usual.
If building a dual root zone, add a layer of burlap and pH-balanced soil over the clay.
Introducing the Plants
Germinate seeds in a potting mix until they have at least two nodes. Then transplant them into a net pot to begin aquaponic growing.
Must-Follow Tips for a Successful Aquaponic Grow
Follow these tips to make the most of your aquaponic farm:
- Check and adjust pH levels: Since fish, bacteria, and cannabis all prefer different acidity levels, pay extra attention to this measure and keep it in a narrow 6.8-7.0 range.
- Watch for algae activity: Many cultivators use phosphoric acid for pH maintenance. This ingredient can lead to algae in the tank, which you should remove on sight.
- Consider switching tanks: Does balancing the needs of your animals and marijuana sound like too much work? Use aqua in vegging and move to an inorganic hydro system for flowering.
- Prune and trim regularly: This growing method supercharges vegetative development, creating a thick canopy that might hinder light penetration. Remove excess leaves or train the plant into a desirable shape for higher yields.
The Bottom Line
Aquaponic growing is a terrific way to improve yields through an innovative and fully organic system. It’s perfect for those who want to keep aquatic animals and cultivate marijuana. For others, it may be a bit more trouble than it’s worth.
The key to success is staying on top of your plants’ feeding schedule and outside environment. Keep them cozy and learn the signs of nutrient troubles to get heaps of sticky, organic buds.
Why not buy seeds and give aquaponic growing a try? This setup takes up less space, makes your garden eco-friendly, and boosts the harvest potential in one clean sweep.
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