aquaponics marijuana

Aquaponics & Cannabis: 3 Major Obstacles

Table of Contents

Introduction: What is Aquaponics?

In order to get high yields with aquaponics, a cannabis grower needs to familiarize themselves with the basics of how an aquaponic system works. To grow cannabis successfully in aquaponics, the system must be configured to produce the high levels of nutrients needed by a plant like marijuana, and that takes a little extra know-how!

Aquaponics is the art of combining aquaculture (growing fish in tanks) with hydroponics (growing plants in water). It’s sort of like organic hydroponics!

In an aquaponic growing system, fish are raised in a tank and the nutrients they produce (contained in their poop and produced by their gills) gets converted by bacteria into nutrients for the plants. The plant roots help clean the water before it is re-circulated back to the fish tank, completing the cycle.

Aquaponics creates a tiny ecosystem – fish make nutrients for cannabis while cannabis cleans the water for the fish!

Although fish are the most common species used for aquaponics, other aquatic creatures like shrimp, crayfish or prawns can also be used. Both edible fish and ornamental fish can be used successfully in an aquaponic system. Generally you want to pick a species that is hardy and can tolerate crowding. Tilapia is an edible fish that adapt very well to aquaponics, and koi or goldfish are great choices for ornamental fish since they are nice to look at and can thrive in sub-optimal environments.

Aquaponics may be the most efficient way there is to cultivate both fish and plants at the same time because combining them together reduces the cost of farming each one individually! In big commercial operations, aquaponics is used to produce profitable combinations like tilapia fish and lettuce. In smaller setups, aquaponics is a sustainable, low-technology and efficient way to create food even with infertile land and low resources – aquaponics dramatically reduces the amount of water needed for raising fish, while producing high-nutrient plants at the same time!

You feed the fish, they feed the cannabis!

When it comes to growing cannabis in aquaponics, one of the big goals is to set up a system that produces high levels of available nutrients. Growing cannabis plants gobble up nutrients, especially in the flowering stage, so you need to ramp up an aquaponics system to optimize it for high nutrient output! That means that you need to make sure you have a high density of fish, as well as a really great bacterial colony to convert all that fish poop into nutrients for your plants!

Life Cycle Inside a Cannabis Aquaponics System


The Rearing Tank / Aquarium is where the fish or other aquatic creatures live. These creatures produce waste containing nutrients that are vital for plant growth. Common fish used in aquaponics include tilapia, koi and goldfish, but there are many other hardy species that can adapt to an aquaponic environment including blue gill and catfish.


Your system will have a Hydroponic Sub-System, which is basically the tank or reservoir where cannabis plants grow with their roots in the water. In many ways, you grow your cannabis plants in aquaponics just like you would with a traditional DWC/hydro setup. The main difference is the fish produce nutrients instead of you having to add them!


Bacteria make up your Biofilter, the “heart” of your aquaponics system. The bacteria biofilter is the missing piece that allows you to run a symbiotic relationship between the fish and the plants like in nature. When you create a nice home for the bacteria, they work hard to convert fish waste into usable nutrients for the plants. The biofilter can be its own separate component in the system, or you can cultivate a biofilm of bacteria inside the actual fish tanks and hydroponic reservoirs. Without a colony of bacteria, your plants will be unable to use the nutrients in the water from the fish (and fish will die from too-high levels of ammonia)!

The Secret to Success with Marijuana & Aquaponics is Patience

The secret to any successful aquaponics system is patience! You need to create a balance between the fish, bacteria and plants, and this takes time. Unfortunately, there’s not necessarily a lot of ways to speed things up while your bacteria is being colonized.

It’s like growing a cannabis plant in a way, you can do things to get the plant to grow faster, but no matter what you’re still going to have to wait for the plant to grow until you get to harvest. You can help your bacteria grow, but they need time to build up their numbers and form a robust colony.

That means in a young/new aquaponics tank you have to spend time cultivating your bacteria, and in the meantime you may have a lot of adjusting to do to maintain a balance that will keep both plants and fish alive: adding nutrients, changing the water, testing nutrient levels, managing pH and possibly adding/removing fish.

But as you create more of a balance, and your tank becomes more mature, you will have a lot less to do. In fact, over time you can set the system to do most of the maintenance by itself!

3 Major Obstacles to Growing Cannabis in Aquaponics

1.) Cannabis Has High Nutrient Needs

Growing cannabis in aquaponics is similar to hydroponics, except fish and bacteria make the food! Your plants can’t use nutrients directly from the fish. Fish waste actually has to be converted to a usable form by the bacteria in your biofilter. Building a robust colony of bacteria for your biofilter can take 6 months or more, which means that additional nutrient supplementation by natural sources will likely be needed to grow a cannabis plant in aquaponics for the first few months.

The appetite of a cannabis plant for nutrients is especially voracious during the budding/flowering stage. When your plant is making buds, it’s sucking up nutrients like there’s no tomorrow! Fruiting plants with similarly high nutrient needs to cannabis (like tomatoes) have been successfully grown in aquaponics, but it’s much less common than growing something with simple and low nutrient needs like lettuce or herbs.

While “getting your feet wet” with aquaponics, don’t beat yourself up if you run into nutrient problems!

2.) May Need Separate Vegetative & Flowering Chambers

Vegetative and flowering cannabis have different nutrient needs for the best growth. So in order to completely optimize an aquaponic system for cannabis it may be necessary to maintain different tanks.

It may be possible to simply supplement your tank with extra nutrients during the flowering stage, but it can be harmful to fish to add an excessive amount of extra nutrients unless the plants use most of it up before the water is re-circulated back to the rearing tank! Extra planning and water testing may be needed to manage which nutrients are currently available.

3.) What to Do with Extra Fish

Aquaponics is spectacular at producing fish and plants at the same time. If a cannabis grower would like a constant supply of fish to eat or sell, an aquaponic system simply can’t be beat!

But if a cannabis grower does not want to actually harvest their fish, they need to plan on what to do with the extra fish as they die and need to be replaced. In order to maintain the equilibrium of your aquaponics system, it’s a good idea to regularly be adding new young fish as old ones mature and die.

Tactics for Growing Marijuana with Aquaponics

How to Produce the Nutrients Needed by Cannabis

Even after your biofilter is established, you may still need to supplement with extra calcium, iron, potassium and possibly phosphorus to keep up with the needs of your cannabis, especially during the flowering stage.

Luckily there are natural sources to get extra nutrient supplementation without seriously affecting your fish. For example Maxicrop is a common nutrient additive made out of seaweed that works well in an aquaponics system to add potassium and trace minerals without hurting your fish.

Other common additives include cycling calcium hydroxide (hydrated lime or builder’s lime) and potassium carbonate (bicarbonate), which add calcium and potassium to the system while also raising the pH (since low pH is common in an aquaponics system that’s not well-established).

No matter what, when dialing in your aquaponic system it’s important to test your water throughout the process to see what nutrients are currently available. This lets you know where you’re running into nutrient problems, and also will help you know what to do to fix it. Not only will this help you take better care of your plants, it will also help you take better care of your fish!

Want to create a complete ecosystem with basically no input from you?

Some growers will introduce a worm farm (vermicompost) to the system to supplement nutrients naturally while breaking down the solid waste from fish which can’t be processed by bacteria. This is one way to actually “complete” the cycle inside the system.

Normally in aquaponics, these extra solids are filtered out and thrown away, but worms can liquefy it while providing an extra source of nutrients that can help bridge the nutrient gap and make sure cannabis is getting everything it needs without any extra supplementation.

At this point your main input into the system would just be fish feed. If you want to get even more sustainable, you could grow duckweed or another plant that fish eat and you wouldn’t even have to buy fish feed anymore! As the system gets more and more balanced, nearly all the energy input to the system can come from the sun or grow lights, producing a food/plant generating machine!

Ready to start growing cannabis with aquaponics? The following incredibly high-rated book will teach you everything you need to know so you can get started today!

Learn how to grow cannabis with aquaponics with Aquaponics Gardening: A Step-By-Step Guide to Raising Vegetables and Fish Together available on Amazon!

By following the tutorials and setting up your system to grow high-nutrient, flowering plants plants like tomatoes or corn, you will be giving your cannabis plants everything they need to succeed!

In order to get high yields with aquaponics, a cannabis grower needs to familiarize themselves with the basics of how an aquaponic system works. To grow cannabis successfully in aquaponics, the system must be…

Growing Cannabis with Aquaponics: An Overview

Wednesday June 12, 2019

W hat if we told you that there’s a way to grow cannabis and provide organic nutrients to your plants directly from their source while giving some home-grown pets a healthy, happy environment in which to thrive? And what if we told you that, after the initial setup, your plants (and fishy pets) would be able to grow on their own with minimal need for outside interference?

The best part? This grow technique already exists and doesn’t require any fancy technology, either. In fact, aquaponics, or the act of growing plants and fish together in the same closed-loop system, has been in practice since 1000 AD by the ancient Mayans who grew plants on rafts afloat lake surfaces. The Aztecs (1300-1521) improved the technology through a series of canals and artificial islands on which crops thrived thanks to the nutrient-rich soil and ample access to water. Today, aquaponics is often used as a means of environmental protection or simply by those wishing to cultivate their own food in small spaces – and, of course, for cultivating cannabis!

What is Aquaponics?

Aquaponics is the combination of fish farming and soilless hydroponics. The premise of aquaponics is that nutrient-rich fish waste can be used to fertilize plants and that plants can filter out the waste to maintain a healthy living environment for fish.

Essentially, fish water is pumped directly onto plant root systems. Then, after the plants have filtered out the waste, the water is pumped back into the fish tank or pond.

Fish are happy, plants are happy, and farmers (who can cut their labor by 75 percent and increase plant size an average of 10 times) are extremely happy. When it’s all said and done, both plants and fish can be harvested and either consumed or sold.

Why Grow Cannabis with Aquaponics

There are many advantages to aquaponic cannabis cultivation that go well beyond easy, accurate nutrient applications. Aside from turning a cannabis crop into a fish farm, aquaponic grows take up considerably less space than soil grows while producing plants that are both larger and denser, as well. Plants also tend to reach maturity quicker thus speeding harvest time and turn-over rate. No other cultivation method produces the volume and speed of an aquaponics grow with such little effort and resources.

Additionally, aquaponic setups do not experience the weed and pest problems that soil grows do which helps eliminate the need for laborious weeding and pesticides like neem oil – a common potential contributor to conditions like Cannabis Hyperemesis Syndrome. Aquaponic grows also use 90 percent less water than traditional cultivation practices which is especially important given scarce water supply.

Best Fish for Aquaponic Grows

Though many different kinds of fish do well in aquaponic setups, choosing the right fish for a cannabis aquaponic grow requires a bit more consideration. First, because cannabis requires more nutrients than, say, lettuce, you’ll need to find fish that do well in crowded, sometimes unfavorable environments. Tilapia is the most common fish type to use in cannabis grows, followed by trout and goldfish because of their reliance and easy adaptability. They also thrive in temperatures comparable to cannabis’s ideal temperature (between 65 and 75 degrees Fahrenheit) and require little attention to survive.

It’s also important to consider what will happen with the fish after harvesting the plants. Though fish have a lifespan of many years, eventually they will need to be displaced or disposed of to prevent excessive crowding. Aquaponics setups usually require one pound of fish for every five to seven gallons of water; if the fish breed, they’ll need to be thinned out for the best results. So, what to do with fish from an aquaponics grow? Should they be eaten? Moved to a more spacious pond? Answers to these questions will largely determine the type of fish to use in an aquaponics grow setup; ornamental fish like goldfish or koi adapt well to outdoor environments whereas edible fish like tilapia and trout can make for a nice entre come dinner time.

Aquaponics is both a fun hobby and an environmentally-friendly cultivation practice. Those with an existing hydroponic cultivation setup can easily modify their system to accommodate aquaponics and will no doubt be pleased with the results.

Have you ever tried aquaponics cultivation systems for cannabis grows? We’d love to hear about your experience.

There are many different ways to grow cannabis, and some are more unique than others, Growing cannabis with aquaponics is not the most popular method around, but certainly is a fun way to take your marijuana cultivation skills to the next level and experience something new! ]]>