DWC Hydroponics (Deep Water Culture Technique)

Deep Water Culture Hydroponics (DWC) is a method of growing plants suspended in water, rather than soil. This may sound complex but we promise it is quite simple!

The Deep Water Culture technique is one of the most user-friendly, low maintenance, and low-cost systems available for hydroponic growers. DWC systems are so efficient that plants can be harvested up to twice as fast as normal soil-grown plants. In this article, we will cover what DWC hydroponics are, how they work, and what you need to know to start your DWC system.

Let’s learn more!

hydroponics 01
Deep water culture (DWC) hydroponic systems grow plants in nutrient-rich water without soil.

What Is DWC Hydroponics?

Hydroponics is just a big word for growing plants without using soil. In traditional gardening, plants are grown in soil which supplies nutrients for the plants’ development.

If you are looking for a foolproof, soil-free microgreens growing kit, try out The Good Box (you can learn more here!)

In hydroponics, the soil is replaced with a nutrient solution composed of water and liquid fertilizer. When plants are grown in soil, the roots extend through the material to find nutrients.

When plants are grown directly in a nutrient solution as they are in hydroponics, nutrients are always surrounding the roots resulting in fast growth rates and plentiful harvests. But, that is only skimming the surface of how hydroponics work and why they are so efficient.

hydroponics 02
In hydroponics, the roots of plants get both nutrients and water from a soilless system.

There are many different hydroponic techniques, one of the most popular and simple being the Deep Water Culture technique.

There are three key elements to a DWC hydroponic system: Water, nutrients, and oxygen. The Deep Water Culture technique is when plants are grown in a reservoir of highly oxygenated water.

The roots of the plant remain entirely submerged in water throughout their entire growth cycle. This is possible because an air pump ensures that the water remains highly oxygenated at all times.

root rot
Normally plant roots rot in soil with too much water. However, oxygenated water in a hydroponic system will not cause the same problem.
Image courtesy of user:
Bjornwireen via:
Wikimedia Commons: https://commons.

The water must also include plentiful nutrients to fuel the growth of the plant. In traditional gardening, it is the soil that provides nutrients to the plants.

In hydroponics, there is no soil involved in the growing process. Hence why liquid fertilizer is an essential component.

Liquid fertilizer is added to the oxygenated water to create the growing solution! The oxygen allows the plants to take in large amounts of nutrients, resulting in accelerated plant growth and large harvests.

Hydroponic systems like the Ebb and Flow or Nutrient Film Technique supply plants with routine nutrient-water cycles. The Deep Water Culture technique is different because it submerges the plants in nutrient water at all times.

The Kratky Method is extremely similar to the DWC technique but the two are different because one is active and one is passive; the Kratky Method does not require electricity while the DWC does.

electrical outlet
You will need electricity to run a pump in a DWC hydroponic system. Consider a Kratky hydroponic system if power is an issue.

If you are a beginner hydroponic gardener, the Deep Water Culture technique is a budget-friendly and easy DIY option that both first-timers and established growers enjoy. Hobbyist gardeners and professionals are both drawn to the DWC system for its advantages:

  • The DWC method is great for people who simply want to assemble the system and let it do its thing. There are no nozzles or water pumps that can become clogged. You just have to remember to check on the air pump to make sure it is working properly and replace the water as needed. 
  • Just a short list of budget-friendly items are needed to assemble your own DWC system!
  • The oxygen-rich nutrient solution is like organic jet fuel for the growth of a plant. Plants grow fast and the yields are impressive.
  • Because the roots of the plants are suspended in water rather than soil, they can expand with barriers and flourish.  

Some of the downfalls of a DWC system include: 

  • can cause plants to drown in low-oxygen water 
  • in this case, it must be replaced rapidly before the plants drown
  • can be a challenge to maintain throughout the entire water reservoir 

How Does A DWC Hydroponic System Work?

The name, Deep Water Culture, is quite self-explanatory: you grow plants in deep water! At first, this may seem a little suspicious considering that many plants die from overwatering.

hydroponics 03
In a DWC hydroponic system, the water is oxygenated by a pump and circulated to prevent root rot.

But, with DWC hydroponics, this is not an issue because the water is constantly oxygenated and loaded with beneficial nutrients for the plants to thrive.  The water reservoir that the plants are grown in is filled with a nutrient solution consisting of water, liquid fertilizer, and oxygen.

The roots of the plant are completely submerged in the water reservoir and can remain submerged for the entirety of their growth cycle. The plants don’t drown because the air pump and air stone ensure that the water remains consistently oxygenated at all times. 

One of the perks of a DWC hydroponic system comes from the amount of water being used. More water in a reservoir means that the nutrient solution is easier to keep stable for the plants to absorb. This leads to less monitoring and maintenance for gardeners. 

If you are growing from a seed, you will see exponential growth once the plants have germinated and the roots meet the water. The Deep Water Culture technique is so efficient because plants always have access to as much water and nutrients as they need.

coco coir coconut fiber mat
Coconut coir is one growing medium you can use for a DWC hydroponic system.

In traditional gardening, plants spend energy expanding their roots to search for pockets of water in the soil. Hydroponic systems provide plants with the opportunity to grow to their fullest potential as easily as possible.

What Do I Need For A DWC Hydroponic System?

Traditional DWCs are the easiest to build and they are great for beginner gardeners and experts alike! This list includes everything needed to start your own DWC system:

  • Bucket/tank for water reservoir
  • Air pump
  • Air stone
  • Airline tubing
  • Net pots
  • Growing media (Rockwool works great)
  • Hydroponic nutrients/liquid fertilizer
  • pH control kit
hydroponics 04
For a DWC hydroponic system, you need a bucket or tank to act as your reservoir to hold the water for your plants.

In simple terms: Connect the air pump to the airline tubing, the airline tubing to the airstone, and place the airstone into the reservoir.

Fill up the bucket with water, meet the ideal pH (5.5 to 6.5), and add your liquid fertilizer. Then, start your seeds!

Here is a step-by-step tutorial we find very helpful from Green Our Planet.

If you are growing your plants from seeds, the growing media that the seeds are in must make contact with the nutrient solution. The media will absorb the nutrient solution for the seed to access.

pelleted lettuce seeds
If you are growing plants (like lettuce) from seed, the seeds will need to contact the nutrient solution.
Photo courtesy of user:
Dwight Sipler via:
Wikimedia Commons https://commons.

As the seed sprouts and the plant matures, the root system will develop, making its way directly down into the reservoir. 

How Often Do You Change Water In DWC?

Generally, it is a good idea to change the water once a week. Ideally, you should not go any longer than three weeks between complete water changes. But, there are factors that are important to consider when deciding how frequently you change the water:

hydroponics 05
Usually, you should change the water in a DWC hydroponic system once a week. This can depend on the plants and their growth stage, though.

Water change frequently depends on:

  • ​The type of plants you’re growing
  • The stage of growth they’re in
  • The size of your reservoir

When it does come time for a full water change, you should gently remove the plants from the reservoir to replace and refresh the hydroponic nutrient solution, then proceed to place the plants back in the reservoir.

Does DWC Need An Air Pump?

When plants are grown in soil, roots still have access to oxygen because of holes and hollows in the material. In Deep Water Culture hydroponics, the roots are submerged in water at all times.

Therefore, the water needs to be well oxygenated to ensure that the plant does not drown. Oxygen-rich water is achieved through an air stone and air pump.

hydroponics 06
A DWC system uses an air stone and air pump to ensure water is oxygenated for plant roots. The larger the tank, the bigger the pump you will need.

It is important to remember to choose an air pump appropriate for the size of your Deep Water Culture system. The larger your system is, the more powerful of a pump you will need.

Many hydroponic systems include air pumps, but not all include air stones. Air stones are an important element of a DWC system because they circulate the air throughout the water reservoir by producing oxygen bubbles.

The bubbles help to fill the reservoir with oxygen and also work to circulate water, ensuring that the entire reservoir is oxygen-rich. 

What Plants Can Grow In DWC?

Varieties of lettuce and herbs are ideal for Deep Water Culture systems. This is because leafy greens and herbs are fast-growing and lightweight.

Lettuce, spinach, bok choy, kale, romaine, and basil and examples of leafy greens and herbs that will thrive in DWC hydroponic systems. Plants like these will be ready to harvest in just a few weeks!

hydroponics 07
Greens like spinach, lettuce, bok choy, and kale are good choices for a DWC hydroponic system, although you can also grow fruiting plants.

Fruiting plants are more difficult to grow in Deep Water Culture hydroponic systems because they require more time and maintenance. Fruiting plants are much thirstier than leafy greens.

For that reason, you will need to monitor the nutrient solution more closely. Many fruiting plants also require a support structure to grow upon which presents another component when assembling the system. But, with a little extra TLC, plants like tomatoes and peppers can grow well in DWC systems.

Final Words

With properly aerated and nutritious water, it is easy for the plant roots to thrive in a Deep Water Culture hydroponic system. You will be amazed at the growth rate and yields that this technique can achieve!

You can continue your hydroponics journey to learn more about other hydroponic methods as well, such as Kratky hydroponics and NFT hydroponics.

You can learn about hydroponic gardens here or growing hydroponic microgreens here.

You can learn about all different types of plants you can grow hydroponically here.

You can learn about aquaponics (and how it compares to hydroponics) here.

To find books, courses, seeds, gardening supplies, and more, check out The Shop at Greenupside!

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About the author:
Sofi is a passionate writer who studied communications and environmental studies at Eckerd College. You can get in touch with Sofi at https://slenzi4.wixsite.com/website.

Sofi L.

Jon M

Hi, I'm Jon. Let's solve your gardening problems, spend more time growing, and get the best harvest every year!

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