What Is Deep Water Culture In Aquaponics? An Appropriate Guide

Nowadays, there are already numerous modern types of farming that are different from the traditional techniques. Of these types, one is the aquaponics system. It integrates two farming systems. One is aquaculture, and the other is hydroponics, into a single system.

Deep Water Culture In Aquaponics – Nutrient-rich water is pumped through pipes to access the roots of plants. These plants are hanging from rafts floating in the water. The raft hanging plants absorb the nutrient-rich and oxygenated water through their roots.

It results in speedy growth. There are seven major components to deep water culture: water, filtration, grow canals, fish tanks, floating rafts, biofilters, water pumps, and aeration.

They all serve critical positions in making the aquaponics system successful and maintaining a good harvest. Moreover, deep water culture is one of the three standard methods used in an aquaponics system.

What makes the deep water culture popular among growers is its capacity to operate in a large-scale setting. We’ll learn more about the deepwater culture in the following sections, particularly its components and functions.

What Is Deep Water Culture?

In deep water culture, the nutrient-rich water is dispersed through pipes to access the roots of the plants that are hanging from the raft.

The Raft Method

The other term for deep water culture is the raft method or floating method because the plants are held by rafts making it appear as if they are floating in the water.

The term deep water culture derives mainly from using a large amount of nutrient-rich water to circulate in the system to serve as the lifeline of the plants and animals.

The hanging plants from the rafts will absorb the nutrient-rich and oxygenated water through the roots, resulting in speedy growth.

Interestingly, commercial farming uses the deep water culture method because it can sustain large-scale production. However, this method is typically used to grow only a single crop type, either lettuce, salad leaves, or basil.

Fish Grow Larger

Perhaps, the good news is the high density of deep water culture to grow fish up to 10 to 20 kilograms of fish per cubic meter of the fish tank, but you can still adjust the density according to your preference.

This is what the concept of deep water culture is in simplistic terms.

Now, we proceed to the major components of deep water culture and their primary functions:

Major Components of Deep Water Culture and their Functions

There are only seven major components of a deep water culture: water, filtration, grow canals, fish tanks, floating rafts, biofilters, water pumps, and aeration.

They all serve critical positions in making the aquaponics system successful and maintaining a good harvest.

1. Water

Water is the backbone of the deep water culture method and the lifeline of both plants and fish. The water is filled with nutrients from natural fertilizers produced by fish wastes.

Though you can still add appropriate fertilizers if you like, the water is then circulated through the canals and reaches every plant hanging in the raft.

The water flows relatively slowly from the fish tank through the help of gravity into the mechanical filter and biofilter.

From there, the water is pumped into two directions through a connector and valves while some water is pumped directly to the fish tank.

The remaining water is then distributed equally through the canals and into the grow canals where the plants are located.

After reaching the plants, the water flows back into the fish tank through the exit canals. The water will flow through the biofilters before it is pumped towards the fish tank.

The whole cycle is completed when the water overflows through the exit pipes from the fish tank, which usually takes 1 to 4 hours, depending on the size.

2. Filtration

The filters seize any solid materials from the fish, plants, or anything that may enter the system. Filters are essential in an aquaponics system because they prevent solid particles from the fish food, fish wastes, and fallen plant roots from circulating in the system which will clog the pipes and nozzles once it has built up.

Filters are responsible for keeping the water flow clean and residual-free inside the system.

In deep water culture, clogging is your greatest enemy. Thus filters are there to prevent that from happening.

3. Water Pump

Another essential component of a deep water culture is the water pump. Responsible for the steady and equivalent flow of water in the system.

Through pumping, the water can circulate from the fish tank, through the filters, and into the grow beds.

4. Grow Canals

Grow canals are like a fish tank that stores water to supply nutrients to the plants. They can be made up of anything as long as they’re strong enough to hold a large amount of water.

They may vary in length, but the ideal width of a grow canal should be the same as a polystyrene sheet with a recommended depth of 30 centimeters to give adequate root space.

5. Floating Rafts

The floating rafts are located at the top of the grow canals, and they are responsible for keeping the plants in perfect place and position. Floating rafts are usually built from Styrofoam, but they can also be made with other lightweight materials with foam properties.

The floating rafts have holes to keep the plants in place while their roots are submerged in the water from the grow canals.

You may also install net pots to improve the stability of your floating rafts and avoid plants from falling into the grow canals.

Although you have filters in place, you have to take other measures to prevent solid materials from entering the system to avoid clogging.

6. Biofilters

A biofilter is an improvised kind of ordinary filter with the primary function of turning fish waste into usable and nutrient-rich food for the plants. Aside from that, biofilters are installed to prevent harmful bacteria from colonizing the system.

7. Aeration

Fish and plants also need oxygen to survive, and aeration is the addition of oxygen into the water. They are as important as anything else to keep the rapid growth of both fish and plants. Air pumps, diffusers, air stones, and more are few material examples that can provide aeration for the system.

Plants To Grow In A Deep Water Culture

Deepwater culture methods are ideal for plants that are lightweight and have minimal root growth.

Hence, it is vital to choose the vegetables that have these attributes and enjoy a moist environment.

Some of these vegetables include:

Lettuce and leafy vegetables


Collard Greens



All these plants are lightweight with minimal root growth and mostly enjoy a moist environment. They have a growth time of 5 to 10 weeks from seeds.

When choosing a plant to grow in your aquaponics system, always consider the size of your system.

If you have a small aquaponics system, select a plant that will make your profit more considerable than the expenses of running the system.

Make your diligence to check for the market to know which plant is highly bought by the consumers.

Advantage and Disadvantages of Deep Water Culture

As with many farming methods, the deep water culture has its advantage and disadvantages that you have to know.

Not only will it improve your knowledge about the deep water culture method, but it can also serve as a determining factor whether or not it fits into your standard.

Advantages of Deep Water Culture:

High-level production with nominal labor requirements

Plant roots can maximize the nutrients in the water

Simple and economical

The harvesting process is easy and fast

It has the most stable water quality and temperature compared to other methods

Low maintenance and space-efficient

Suitable for backyard farming and commercial production

Disadvantages of Deep Water Culture:

• Restrictive when it comes to planting options

• Unsuitable for fruits and root crops

• It can be a mosquito breeding ground if the design is faulty

• The water from the raft edges and tank may evaporate if there are gaps

• It requires filtration, which translates to additional expenses

• Regular filter clean-ups can be a hassle

• Roots are vulnerable to microbial infection if the biofilters are not working properly

• Oxygen is needed most of the time because the roots are submerged in the water, and this will also add to your expenses by using devices for aeration.

Final Thoughts on Deep Water Culture In Aquaponics

By this time, you already have enough knowledge about the deep water culture method. Don’t forget that aeration is vital in a deep water culture method. Thus it has to be maintained for the benefit of both fish and plants.

Aside from aeration, the pH level of water also needs to be checked. The pH level of your water should be appropriate for the fish and plants you are growing in the system.

Make the necessary effort to scan the pumps and other piping to see if there is a leakage.

Don’t forget to include the filters when checking the system to see if any solid materials have clogged the filters.

Lastly, deep water culture is one of the many easy-to-handle systems, as long as you know the fundamentals.

The greatest reward of this type of farming is the happiness and satisfaction it can give, and deep water culture is more than capable of doing that.

Patricia Godwin

Patricia Godwin

Patricia has many years of experience as a content writer on various subjects, but her first love is gardening. She’s never met a plant she didn’t like and, consequently, she writes about every type of plant you can think of. Once an avid gardener with a herb garden, a succulent rockery, and a rose garden – to mention a few. Nowadays, she’s constantly on the move searching for interesting plants to bring to your attention; and explain to you all the details you need to grow, care and maintain these plants.

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