How to Choose the Right Grow Bed for Aquaponics

Media based is one of the most popular methods for home growers of small-scale aquaponics systems. The design has a low initial cost, is space-efficient, and is recommended for aquaponics beginners because it is easy to set up and maintain. If you're planning to set up a media based aquaponics system, one of the essential things you need to consider is the grow bed. 

Getting the right grow bed for your media based is critical to your system's success, as it is one of the main components of a media based aquaponics system. It is the foundation of your media based aquaponics system and the place where plants are grown and nurtured. This article will discuss the necessary factors you need to consider in choosing the right grow bed for your media based aquaponics system. 

Why is Grow Bed Important?

If you have a media based system, the grow bed is the container for the water, grow media, and plants. It is where your plants are grown and nurtured. The grow bed is an ecosystem unto itself, just like the fish tank. Because it is filled with grow media, it acts as a biofilter, where the fish waste breaks down as it passes through the grow bed. 

It is also where the bacteria grow and break down fish waste into nutrients that can be available for the plants to use and thrive. When the water goes into the grow bed, the plants take the nutrients before the water returns to the fish tank clean and ready for the next cycle. 

The Grow Bed Relation with The Fish Tank

Your grow bed should be in the correct dimension for your aquaponics system. The measurement of your fish tank and the size of your grow bed should be related. This is because the amount of fish waste will dictate how many plants you can grow in your grow bed and how they will flourish. 

Too many fish or the amount of fish food will equate to an excess of ammonia and nitrates. If your grow bed media is insufficient, this excess will slowly poison the water for the fish. Too few fish, and you will need more nutrients for your plants. So, to have a successful aquaponics system, you need to understand the best ratio between the grow bed and the fish tank. Having stability in the amount of fish waste in its food ensures a successful system. 


Grow Bed in Aquaponics

Things to Consider in Choosing the Right Grow Beds for Aquaponics

  • If you're a beginner in aquaponics, you have to begin off with a 1:1 ratio of grow bed to your fish tank. This means that the whole volume of your grow bed equals the quantity of your fish tank. This ensures ample filtration. Once your system is established and you know the ins and outs of aquaponics, you can quickly expand your system.
  • Choose a grow bed that is made of food-safe and non-toxic materials. 
  • The grow bed must be thick and strong enough to hold the weight of your grow media, plants, and the force of constant draining and filling of water.
  • Avoid using grow beds with metallic substances as they corrode rapidly, which can affect the pH of your aquaponics system
  • The grow should be deep enough to hold the root system of various plants.
  • Ensure that the grow bed you choose is waterproof to ensure that no water escapes your system. 

Understanding The Three Aquaponics Grow Bed Zones

The grow beds in a media based aquaponics system have three grow bed zones. These zones serve an essential function in your aquaponics system. It is a good idea to learn the importance of each zone because it will help you determine the right grow bed size and depth for your system.

1. Zone One - The Surface or Dry Zone

The surface or dry zone is located on the first 2" of the grow bed. These areas need to be kept dry as it helps prevent evaporation and protect the plant base against collar rot. Keeping this area dry will also prevent algae growth on the surface area of the grow bed media and moisture-related diseases such as powdery mildew.

2. Zone 2 - The Root Zone

The root zone is between 6 to 8 inches deep into your grow bed and is constantly flooded and drained. These are where root growth and plant activities happen. During the drain part in the flood and drain cycle, the water will completely drain away, allowing for the efficient delivery of oxygen-rich air to the roots, beneficial bacteria, microbes, and composting worms (if present in the system). During the flooding part of the cycle, the incoming water helps spread moisture, nutrients, and incoming solid fish wastes throughout the area.

3. Zone 3 - The Solid Collection or Mineralization Zone

This zone is located at the bottom 2" of the grow bed. This zone is where fish wastes and worm castings are collected. What is left of the solids during the flood and drain cycle is in this zone, where further and final mineralization occurs with the help of beneficial bacteria and earthworms.

The Importance of Grow Bed Depth

The depth of your grow bed is essential, but there is no right and wrong to grow bed depth choices. It will depend on what you see your system needs and the type of plants you plan to grow. However, most aquaponics experts recommended using a grow bed with at least 12" of media depth with at least 1-2" on the top left to dry to prevent algae and fungal growth. 

Deeper grow beds are more costly because they will need a lot of grow media to fill them. But if you use a shallow grow bed, there will also be limitations on what plants you can grow. Below are the factors you need to consider in choosing the depth of your grow bed.

1. Choice of Shallow or Deep Grow Beds

Experts recommended a standard grow media depth of 12 inches, which should be enough to keep the system working and support the plants' root system. However, a shallow grow bed can also be used as long as the plants you're planning to grow do not have a large root system. Grow beds with a standard depth of 12 inches can grow almost any plants, while a shallow grow is best suited for plants like lettuce and other leafy greens. 

Advantages of Using a Shallow Grow Bed:

  1. Cheaper 
  2. Easy to fill with grow media
  3. Great for growing leafy greens 

Disadvantages of Using a Shallow Grow Bed:

  1. Limited to shallow-root plants
  2. It can't provide the base for plants with larger root zones, such as tomatoes and cucumbers.
  3. A dead zone (anaerobic area) may develop, so you need to clean your grow bed to prevent dead zones from developing. 
Advantages of Using a Deep Grow Bed:
  1. A deep grow bed can grow a variety of plants.
  2. Deep grow beds can provide enough surface areas for the beneficial bacteria to colonize.

Disadvantages of a Deep Grow Bed:

  1. More expensive to fill with grow media.
  2. Heavier than the shallow grow bed, so you need a structure that can withstand the weight of the grow bed. 

2. The Types of Plants You Want to Grow

The size and depth of your grow bed will affect what type of plants you can grow. A shallow grow best works well for shallow-rooted plants but won't work for deep-rooted plants like tomatoes. So if you plan to grow fruiting plants such as cucumbers, eggplants, and tomatoes, you can opt for a grow bed with at least 12 inches in depth. 

3. Your Budget

Your budget is a factor in choosing a grow bed for your media bed aquaponics system. Some materials are budget-friendly, while others are expensive. Consider your budget and stay within that limit. You can also use recyclable materials as your grow bed if they are sturdy enough to hold the water, grow media and plants, and are food safe. 

4. The Size of Your Fish Tank

Your grow bed should be in the correct dimension for your aquaponics system. The measurement of your fish tank and the size of your grow bed should be related. This is because the amount of fish waste will dictate how many plants you can grow in your grow bed. 

Too many fish or the amount of fish food will result in excess ammonia and nitrates. If your grow media is insufficient, this excess will slowly poison the water for the fish. On the other hand, you need more fish to have enough nutrients for your plants. 

Aquaponics Grow Bed Ideas

You can purchase a ready-to-use grow bed or make your DIY grow bed. Sourcing or making your own grow bed is easy; here are some commonly used grow beds for aquaponics to give you ideas and help you get started.

1. IBC Grow Bed

One of the most common aquaponics grow beds is the IBC totes. This grow bed is used mainly by DIY aquaponics gardeners in media-based or flood-and-drain aquaponics systems. The IBC totes are recycled and used as grow beds and fish tanks.

 IBC totes are ideal grow beds in aquaponics because they are durable and easily modified to suit your specific needs. Because IBC Totes are mostly used, the most important thing to remember in using IBC totes as grow beds is to know what was in the IBC totes you are buying. Fish are sensitive creatures, and chemicals that used to contain some IBC totes might affect the health of your fish and plants. Use only IBC totes that are previously used for food products.


IBC Grow Bed for Aquaponics

2. 55 Gallon Barrel Grow Bed

Another grow bed idea popular to DIY aquaponics growers is the 55 gallons barrels that are repurposed into grow beds. Barrels are readily available and economical. All you have to do is cut the barrel in half, and you'll have your grow bed. However, ensure that the barrels are cleaned before using them as your grow bed. Some barrels used to contain chemicals that can poison your new aquaponics system.


Barrel Grow Bed

3. Old Bath Tubs

Old bathtubs have been recycled into grow beds by several backyard aquaponics gardeners. Using old bathtubs will allow you to grow a more extensive aquaponics system. However, just like any other grow bed, ensure they clean the bathtub and are chemical-free. 


4. Wood Framed Bed with Pond Liner

Wood-framed grow some DIY backyard aquaponics gardeners also use beds lined with pond liners. The great thing with a wooden grow bed is making a specific size that fits your aquaponics system's needs. It is made of a simple wood frame with a wooden floor and a plastic pond liner to ensure the water stays where it should be. Make sure to varnish or paint your wood to protect it from termites. 


Wood Framed Grow Bed with Pond Liner

5. Aquaponics Grow Bed Containers

You can use ready-to-use aquaponics grow bed containers if you have no time for DIY grow beds. It might cost you a little, but these grow beds are thick, durable, food-safe, and explicitly made for aquaponic gardening.


Aquaponics Grow Bed Conatainer


As one of the essential components of your media-based aquaponics system, you must choose what grow bed to use. There are many aquaponics grow beds that you can use in your system, but what you think is the best suitable one will depend on the size of your fish tank, the plants you are planning to grow, and your budget. 

Remember that your grow bed's function is to hold your grow media, provide enough space for filtration, and provide enough planting area for your plants to grow. So choose the ideal grow bed depth to ensure your plants' growth and health.


1 Response

Anthony Daly

Anthony Daly

August 22, 2023

Thank you for providing important information for a new grower. I have had trouble sourcing grow beda and thought the wooden idea is great.

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