Deep Water Culture Hydroponics – The Ultimate Guide

Deep Water Culture Hydroponics

With the latest innovations in agriculture, it’s no longer essential for farmers to grow plants with soil, and hydroponics make a great solution. The different hydroponic growing methods include deep water culture where the plant roots are deeply submerged into water, often deeper than 8 inches.

However, deep water culture hydroponics requires using specific methods with a list of items needed. That’s why you can use this guide to learn everything it takes for a deep water culture setup, growing trays, and other items, and how it works at a glance. Let’s get right into it to help you consider the bigger picture behind deep water culture!

Deep Water Culture Basics

Hydroponic Lettuce
Hydroponic Lettuce

The deepwater culture system is widely used not just for home plant growing, but for commercial purposes as well. Whether it comes to professionally-built growing trays with direct nutrition intakes such as large connected fish waste aquariums, or just a small household trayOpens in a new tab., the principle is the same.

One of the key takeaways from this hydroponic method is that plant roots need to be submerged in the water. However, the plants are usually placed into baskets and they are placed above the tank with hydroponic nutrition. Before thinking about the deepwater culture further, take a look into the needed items for building the system:

  •       Growing tray
  •       Air pump
  •       Plants/seeds
  •       Hydroponic nutrients
  •       Growing media
  •       Soaker hose
  •       Plant baskets
  •       pH instruments

So, how do these items help the plant grow even without soil and its nutrients? First, it’s crucial to place the plants into baskets or cup holders with a lid opening so that the roots can reach the water in the tray.

It’s not only necessary for the roots to come in touch with the water – they have to be submerged at all times with no exception. Don’t think that this would damage your plant in any way as you are trying to recreate the function of the soil with this type of system.

Understanding Deep Water Hydroponics

Let’s go through a quick overview of the main water culture method functions before getting into the different types of the system. Once the plant roots are submerged in the water 24/7, the plant will get the nutrients needed for growth through them.

The roots will absorb the nutrients from the water tank as it’s filled with substances that act as substitutes for regular soil nutrients. And what about the oxygen intake, you might wonder? Well, that’s sorted out as well due to the mentioned soaker hose or pumps that create bubbles in the tray and provide oxygen.

The water tank itself generates oxygen as well, only in smaller amounts so the pump is needed to make sure it’s on the right level. The air bubbles from the pump should be active in the sense that they raise high enough to go in direct contact with the roots.

In commercial agriculture, the large air pumpsOpens in a new tab. are paired with hoses that act as an intake of nutrients from a fish farm tank. This is how the natural order is created since fish are fed and their waste is brought to the growing tray of the DWC.

Of course, you can use another type of nutrient with smaller trays suitable for home use. Now that you know the essentials of how the system works, it’s time to get into more details. The deepwater culture always works on the same principle, but it’s the nutrient type and oxygen generating method that greatly differ.

Growing Media And Nutrients

Now that we’ve discussed the basics, it’s time to get into it with the first thing that you will need before you even set up a tank – media and nutrients. The nutrients are the most important item due to their role in replacing natural soil nutrients.

To help grow your plants properly with the best health conditions for their advancement, both macronutrients and micronutrients are essential. Growing media is also important as it helps contain the roots within the water tank. It also provides enough moisture which is needed to create a growing environment for the plants.

Hydroponic Growing Media - Coconut Husk
Hydroponic Growing Media – Coconut Husk

Importance of Growing Media

Achieving proper moisture around the plant root is essential not only for proper plant growth but also for the taste of a formed plant used as food. You can use different sorts of media that add up to the moisture around the roots of your plants.

With the water culture method, you can include perlite, gravel, pebbles pelletsOpens in a new tab., and coconut husk as just some of the growing media. The thing is that growing media helps you control the moisture level which is crucial for preventing plant disease, lower crop yields, and balanced growth.

On the other hand, some types of plants need less moisture and they vaporize a bit of water that they give back to the tank. This moisture is bad for the plant and they don’t need any more humid environment.

To get to know what’s best for your plant with the deep water hydroponics system, you should double-check the info for every plant type. In essence, seedlings need the most moisture at the start of their growth. Later on, the humidity level between 70% and 85% at the beginning of development reduces to as much as 35% in the weeks to come.

You can use the pH measurements and humidity meters to adjust the environment in your water culture system to suit the type of plant you are growing.

Deep Water Culture Nutrients

When it comes to deep water culture nutrients, it’s important to make a difference between the two types. Macronutrients are Nitrogen, Phosphorus, and Potassium primarily and their ratio is often referred to as the NPK ratio.

It’s the first step towards achieving the quality nutrient growth tray for your plants and the ratio is often given on water culture nutrient products. You can find different nutrient productsOpens in a new tab. that serve as nutrients that cater to different plant types.

The best ratio for starting your seedling’s development is with high Nitrogen, moderate Phosphorus level, and moderate to higher Potassium. The micronutrients are Iron, Copper, Chloride, and Zinc among others.

You need to ensure that your growth tray has a proper mixture of both, as stated specifically for each plant type. Different plant types require different nutrients, and the nutrient level also differs based on the DWC method. So, we’ll also discuss the main water culture methods you might want to use to give you a proper headstart:

Types of DWC Methods

For the best deep water culture setup, you might want to consider the different types. Each water culture method is different in terms of oxygenation and the water circulating technique. Here’s a brief overview of the most common systems that we’ll go through in more detail:

  •       The Kratky method
  •       Falling water
  •       Air bubble method
  •       The recirculating deep water culture system
  •       Aquaponics system

These are not just variations of different deep water culture methods – they can also be considered slight variations and combinations of a few systems in one. Let’s explain things a bit better with a thorough review of each method.


Hydroponic Methods
Hydroponic Methods

The Kratky Method

With the Kratky MethodOpens in a new tab., you will have the opposite of recirculating a deep water culture system as the nutrients in the tank don’t circle back to the tray after reaching the plants. Moreover, there’s no air pump in this situation.

Instead, the plants are held in baskets that are hanging above the growth tray. The roots still reach the growth tank with all the proper nutrients, only this time the gap is there between the plant basket and the water level.

Because of this, higher oxygenation is ensured and there’s no need for a water pump with the Kratnky method. The deepwater culture hydroponics referred to as the Kratky method starts with the plant basket being in touch with the water tank level. However, as the seedlings grow, the roots absorb nutrients and the water level reduces.

Since this is a non-recirculating deep water culture system, the water level stays below the initial level and the gap is formed. This method can replace for the air bubble pump to still provide oxygen to the plants even without the need for electricity. Still, without the air pumps, the minerals and nutrient residue could remain at the bottom and plants might not develop properly in this case.

The Falling Water Method

The Falling Water method is a run to waste version of deep water culture hydroponics and it’s also used without the air pump. However, there’s a big difference between this system and the Kratky method. Instead of relying on the air gap to oxygenate the plants, the Falling Water method relies on water intake.

In other words, water is dropped into the growth tank and the splashing creates bubbles and oxygenates the tank. The other side of the coin is the water outlet in the tank where the water falls to waste to ensure that the tank isn’t too filled up.

It’s one of the methods that are mostly used in commercial agriculture with large hoses from which the water falls. It might be a bit difficult to recreate this system at home.

Air Bubble Method

The air bubble method requires an air pump and air stone to provide the growth tray with enough oxygen so the plants can grow regularly. The air stone is used to help create the bubbles from the water intake that arrives from the pumps.

With the type of deep water culture hydroponics, it’s all up to oxygenation and you can set up the oxygen level depending on the type of plant you are growing. You need the smallest bubbles possible to get the most out of this method and oxygenate the plants accordingly. For this purpose, you can use the soaker hose instead of the air stone option.

The soaker hose provides small bubbles without the need for the stone pores. When these small bubbles come into contact with the water, they compensate for dissolved oxygen taken up by the plant roots.

The recirculating deep water culture system

As the primary method used for growing a large number of plants, you can use the recirculating deep water culture method. It relies on the once central reservoir with tube connections to the plant reservoirs. The water flows to fill the tank, and the remaining water is filled back into the reservoir with an overflow tube.

Because of this, you will never need to check the water level and it can save you a lot of time you would regularly spend on this. You only need to ensure that the central reservoir is always properly filled. With this system, you can also only have an air bubble pump in the central reservoir instead of in the smaller plant tanks.

This can be considered both a positive and negative aspect, as your plants would benefit more with individual pumps that blow bubbles near the roots.

Deep Water Culture Aquaponics

As a unique option for deep water culture hydroponics, the aquaponics method serves great for providing natural nutrients to the growth tray. It’s what we mentioned at the beginning of our journey through the deep water hydroponics system guide.

With this option, you will have two tanks – one below the plant baskets and one fish tank. The waste from the fish tank is directed into the growth tank as a nutrient, and the plants can benefit from the natural waste found in their tray.

It’s one of the best deep water culture nutrients as it recreates the natural order and gives a natural substance for plant growth.

Final Thoughts

Hopefully, now you are equipped with all the pieces of advice you can use to get the most out of deep water hydroponics. With the right approach to deep water culture setup and the different methods, as well as nutrients needed, you can grow plants without soil with utmost success.

Regardless if you plan on using the DWC system for household use or a commercial one, the listed methods make the best solution for replacing organic nutrients found in soil.

Frequently Asked Questions (FAQ):

What is deep water culture?

Deep water culture is a form of hydroponics where plant roots are submerged in water and the right oxygenation way is used in the nutrient tank to ensure the proper growth of your plant.

What is the difference between deep water culture and hydroponics?

Deep water culture is a form of water culture hydroponics where the plants don't float on the top of the water level. Instead, they are set a little bit higher so only the roots come in contact with the water, often submerged for more than 8 inches.

How often do you change the water in the DWC?

The nutrient solution in your growth tray can’t last forever and support your plants through the entirety of their growth. Instead, you should replace the solution in the tank every couple of weeks.

What nutrients are needed for DWC systems?

Both macronutrients like Nitrogen, Potassium, and Phosphorus and micronutrients like Copper, Chloride, and Zinc are needed for proper plant growth.

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