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 system and the place where plants are grown and nurtured. This article will discuss the necessary factors you need to consider in order to choose the right grow bed for your media based aquaponics system.
The Importance of A Grow Bed
The grow bed is the container of the water, media, and plants of your system. 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 grows and breaks down the fish waste into nutrients that can then 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.
Grow Bed Relation with The Fish Tank
Your grow bed should be in the right dimension to 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 the excess of ammonia and nitrates. If your grow bed media is not sufficient, then this excess will slowly poison the water for the fish. Too few fish, and you will not have enough nutrients for your plants. So, having a successful aquaponics system, you need to understand the best ratio between the grow bed and the fish tank. Having the stability between the amount of fish waste into its food ensures a successful system.
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 already know the ins and outs of aquaponics, you can easily 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 a wide variety of plants.
- Ensure that the grow bed you’re choosing is waterproof to ensure that no water escapes from 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 the area 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 are in this zone, where further and final mineralization occurs with the help of beneficial bacteria and earthworms.
Grow Bed Depth
The depth of your grow bed is significant. 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. 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.
If you’re planning to grow only short-lived plants, you can go for shallow beds, but if you’re planning to grow deeply rooted plants, you need to choose a grow bed with more depth. Short–live plants like lettuces and greens can grow in shallow grow beds. But when it comes to deeply rooted plants like cucumbers and tomatoes, shallow beds can’t provide the base for them to grow and spaces for their larger root zones.
Aquaponics Grow Bed Ideas
You can purchase a ready-to-use grow bed or make your own 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 keep in mind in using IBC totes as grow beds is to know what was in 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.
2. Gallons Barrel Grow Bed
Another popular to DIY aquaponics growers are 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, make sure that the barrels are cleaned entirely before using them as your grow bed. Some barrels are used to contain chemicals that can poison your new aquaponics system.
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, make sure that they cleaned the bathtub and chemical-free.
4. Wood Framed Bed with Pond Liner
Wood-framed grow beds lined with pond liners are also used by some DIY backyard aquaponics gardeners. It is made of a simple wood frame with a wooden floor and a plastic pond liner to ensure that the water stays where it should be. The great thing with a wooden grow bed is making a specific size that fits your aquaponics system’s needs. Just make sure to varnish or paint your wood to protect it from termites.
5. Aquaponics Grow Bed Containers
If you have no time for DIY grow beds, you can use ready-to-use aquaponics grow bed containers. It might cost you a little, but these grow beds are thick, durable, food-safe, and made specifically for aquaponic gardening.
As one of the essential components of your media based aquaponics system, you must make the right choice in 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.
Keep in mind 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. Make your decision based on these three main grow bed functions, and you will never go wrong.