If you're new to hydroponics gardening, words like "deep water culture" may sound overwhelming. Whether you are used to soil gardening or a complete newbie to hydroponics, you should know that deep water culture hydroponic systems are the easiest to maintain. With a bit of know-how and planning, you can have your DWC system up and running in no time.

Deep water culture is a hydroponic technique often used by hobby gardeners. Still, it can also be used by commercial growers. It is practical and easy to set up, making it a standard system for hydroponic gardeners.

This article is intended for those aiming to get comfortable using hydroponics. This is a great starting point with using deep reed cultures. What is a deep water culture system, and how does it work? Pros and Cons. Deep Water Culture Methods and how to build one of your own so you can get started with hydroponics in no time.

What is a deep water culture (DWC) system, and how does it work?

A deep water culture system is a hydroponic gardening method that uses an inert medium such as gravel or clay pebbles to support the plant's roots. It is called Deep Water Culture, as the plants are placed in buckets and then filled with water.

This is unlike other hydroponic systems, as in Ebb and Flow, Aeroponics, Drip System, where plants are watered on a constant basis.

An air pump sends air bubbles into the bucket, which provides oxygen for the plant's root growth while also creating pockets of carbon dioxide at the top of the water.

Benefits of deep water culture

  • The benefits are that the bucket will never overflow.
  • Cleaning of the system is minimal, and this helps you keep your food clean.
  • These systems use less water than other hydroponics systems.
  • This method eliminates the risk of over or under-watering for beginners, so it's effortless to maintain appropriately.

Downsides of deep water culture

  • Plants grown in water culture systems are not as strong and large because they don't get much oxygen.
  • Root system cannot be seen or easily monitored without pulling plants out of the water, so it can be hard to tell how well they are doing
  • It is essential that you keep your pump on at all times, which can lead to an electric bill increase

Deep Water Culture Methods

There are a few methods to set up a deep water culture system:

1. Using Air Pump and Airstones

what is deep water culture system

The first method is to use an air pump with an air bubbles stone diffuser. This setup creates the perfect environment for growing plants due to air bubbles rising that provide oxygen while also creating pockets of carbon dioxide at the top of the water. You will need:

Container

Deep water culture containers that can hold at least ten gallons each or more than two cubic feet (per bucket). 

One way to find out if your container will work for deep water culture is by filling up the container with five gallons of water. If it overflows, it's not big enough for DWC. The best containers are dark-colored plastic, keeping light from getting into them, which means no algae growth on the walls!

Airstone

An air stone increased oxygen level, which plants need to grow. These stones also help air bubbles form on top of the water, which gives your system more stability, making leaks less likely to happen over time.

PPM Meter

A PPM meter is a unit of measurement for measuring the level of the nutrient solution, which can be used to help determine whether you are feeding enough or too much.

As your plant grows and changes color, its nutrition requirements will vary. 

  • Seedlings need about 100-250 ppm. 
  • Plants in the vegetative should have around 300-400 ppm during the first half of Vegging, 450-700 ppm during the second half
  • Fertilizing with up to 950 PPM for flowering plants in flower
  • Plants that are done flowering should be fertilized with up to 1,600.

Air pump

You'll need an air pump for your system as it provides oxygen and creates air bubbles at the top, which make up pockets of carbon dioxide that plants need. The best type of pumps are ones with a diaphragm or needle valve. This is adjustable, so you can control how fast water levels rise in buckets over time.

In addition, you'll need:

  • Air pump
  • Net pots, grow media, and plant(s)
  • Airline tubing
  • Hydroponic nutrient solution
  • PH control kit

To set up your system, you will start by:

  1. Filling your bucket with gravel and then adding a net pot at the bottom.
  2. Connect the air pump to the airline, the airline to the airstone, and place the airstone in the reservoir
  3. Add some hydroponic nutrient solution to your proper PH water reservoir.
  4. Use the PH control kit to maintain a balance in your nutrient solution. The average plant needs something between 5.5-6.5.
  5. Place plants into net pots with grow media. You can use seeds or cuttings for this. If using seeds, cover them up with about an inch of gravel before adding more grow media on top. Add fertilizer as instructed by the manufacturer, and then add water until they are submerged in the medium. If using cuttings, just place them directly onto the Rockwool after moistening it first.
  6. Adjust airflow from the pump based on how high your bucket is above ground level-the higher up you are, the less dissolved oxygen there will be, leading to stunted.

2. Recirculating Deep Water Culture

Recirculating Deep Water Culture

The second method is called recirculating deep water culture. It works like an ebb and flows system, but the nutrient solutions never drain/get out of the system. 

In recirculating deep water culture practices, the solution is pushed in a circle through the buckets before returning to the tank. The water stays in that same bucket in a traditional deep water culture system; it does not move anywhere else. 

This is an excellent system for gardens that want to grow many batches of plants at once. 

This setup involves more components and steps to set up, but it also offers a lot of advantages that the first one doesn't have:

  • A central reservoir to hold the nutrient-rich solution
  • Large air pump and air stone
  • Inline water pump
  • Tubing for each bucket 
  • Net pots for each plant
  • Growing medium of your choice
  • pH meter and kits 
  • PPM meter
  • Hydroponic nutrient solution
  • Multiple dark-colored containers or buckets 

Here are the steps to set up this system

  1. Designate one of your containers to be your central reservoir where the deep water culture nutrients and water will be stationed.
  2. Inside the reservoir, set up and attach the inline water pump. You need to have an air stone and air pump in the large tank.
  3. Once you have decided on how many containers you want to have in your system, cut out holes on each side of the container and attach the piping. Ensuring that they all connect back to the reservoir. Make sure also to put an air stone in each container.
  4. Each plant that you put in the container needs to be in its own net pot. If you cannot purchase net pots, you can buy regular plastic pots and make large holes in the bottom so that the plant's root system has room to reach down into the water. 
  5. After you place your plant in the pot, fill the pot with your growing medium of choice. Most growers like to use perlite or clay pellets. Some plants grow better with other mediums to check what works best with what you are trying to grow. 
  6. Each plant needs different types of pH levels to grow correctly.

3. The Kratky Method

The Kratky Method

Image from fifthseasongardening.com

The Kratky Method is the easiest method of deep water culture hydroponics that relies on natural convection to provide the plants with properly oxygenated water.

This method does not require any electricity, and it has minimal setup time because there are no pumps required either! The only thing you need to do is put your net pots in the container filled with growing medium and nutrient solution. Fill them up about halfway so they can still fit underwater (if using cuttings), or cover them if no visible roots are growing yet.

One key in the Kratky method is to leave an air gap between the plant's roots and the surface of the nutrient solution. Air gaps ensure plants get both water and oxygen.

As the plants grow, the water level will decline as plants absorb the water in the system, leaving a gap of the root mass exposed to the air. The "air gap" is essential because it is where the plants respire.

4. Bubbleponics

bubbleponics

Bubbleponics is quite similar to deep water culture hydroponic gardening. The only difference is that bubbleponics uses an air pump and drip irrigation feeding tubes to dispense nutrient concentration to plant root mass.

Deep water culture systems typically don't use feeding tubes and instead utilize an air pump to construct a constant flow of nutrient solution so that the plant roots can receive the nutrients they need.

Here is how it works:

What plants are recommended for DWC?

Plants that grow in deep water culture are often soft-stemmed plants like lettuce, basil, and other leafy greens. It is also possible to grow many types of fruit in RDW cultures-strawberries are one example.

Besides that, you can grow many types of herbs, peppers, tomatoes, and other vegetables.

Answering some of your questions

How often do you change the water in a DWC system?

When the oxygen rich water level of your tank reaches its max, it's time to drain and refill with clean water. This prevents over-accumulation of nutrients, bacteria, fungus, and other unwanted microorganisms so you can maintain a thriving system.

How much water do you need for Deep Water Culture hydroponics?

The amount of water to use in a water culture system depends on the size of the system you are using. Typically, a reservoir with at least 5 gallons can produce about a square foot of vegetable production.

What does pH stand for in DWC Hydroponic systems?

pH is a measurement of how acidic or alkaline something is-a a reading over seven indicates it is alkaline. Below seven is considered acidic.

Suppose your system's pH level dips too low or goes over the acceptable range of 5.5 -6.5 for optimal growth. In that case, you can add a buffer to the reservoir or use a liquid pH adjuster. However, it will be essential to monitor this element based on your plants' current growth stage. When they're experiencing the vegetative phase, you want pH levels to be higher. When approaching flowering phases, you want them to lower.

What does EC stand for in DWC Hydroponic systems?

In hydroponics, EC is the measurement of a solution's electrical conductivity. The EC tells you how much nutrient solution your water can hold and also provides insight into whether the nutrients in your water need to be replenished or if they're at adequate levels.

Pure water does not conduct electricity. Once minerals are added to the water, the dissolved salts increase their ability to conduct electricity. The more concentrations of salts that there are, the higher amount of electric conduction.

How do I know how much oxygen is in my nutrient solution? 

Dissolved oxygen sensors cost a lot of money and may not be necessary for those seeking generalized information. The best way to monitor your dissolved oxygen levels is simply to do the things that ensure they are good. This includes keeping the solution at the right temperature and running an air pump.

What temperature should deep water culture be?

One downside to deep water hydroponics is that it can be challenging to keep the temperature of your reservoir regulated. Only allow the reservoir's water to reach a maximum of 68°F (20°C); otherwise, the dissolved oxygen levels will drop.

Place an indoor thermometer in the enclosure to keep track of the temperature, as well. Be sure that it doesn't get below 60°F (16°C). Suppose the plants are moved into a new seasonal zone due to lower temperatures. In that case, they may start sending more energy towards flowering, resulting in earlier harvesting instead of later harvesting in warmer months.

Why is pH dropping so fast in DWC?

A pH drop could be due to too much nutrient solution, a lack of aeration, or both. Suppose the reservoir is oxygenated (bubbling), and you still see an acidic reading on your machine. In that case, it may be beneficial to add more hydroton rocks into your system for increased water level height.

How much light does DWC need?

The amount of light affects how well photosynthesis occurs, which impacts the growth rate of all vegetables grown under deep water culture methods - including marijuana! Start with 18 hours of light a day but don't forget that you'll need to account for the natural cycle of sunlight as well.

A nutrients problem can arise when light is too intense, which will make it difficult for plants to absorb all necessary nutrient solutions and vitamins. If this occurs, consider using shade cloth or other covering in your enclosure so they are not exposed to such an intensive level of light.

Can I use coco coir in Deep water culture?

Coco coir is a sustainable material used in deep water culture because it does not need to be replenished or replaced very often. It also works well with hydroponic systems because of its ability to hold lots of moisture and provide aeration for plant roots development due to air pockets found inside coco coir blocks.

You will want to use about two inches worth per gallon capacity. This allows enough space between the root system and the water surface, preventing choking out from lack of oxygen. Be sure not to compress your coco when using it-it should feel like loose soil would!

How much space does DWC require?

The size requirement really depends on what kind of system you're building - from setups with just one bucket up to those with multiple buckets and reservoirs! The smaller systems may be outfitted inside your home. Still, again, depending on their size, larger ones could eat up most available outdoor space.

Are plants growing faster using the deep water culture method?

Every plant will produce differently depending on how much light they receive, how often they are watered, what deep water culture nutrients are being given, and many other factors like temperature, etc.

However, plants growing in DWC systems (or most hydroponic systems) will grow at least 15% faster.

Conclusion

Deep water culture hydroponics is a widely used hydroponic technique often used by hobby gardeners. It is also effective. It is easy to set up and maintain. Keep up the easy usage this way is highly effective.

For those wanting to use a starter hydroponic method, this is an easy fit. It's also cheaper and more appropriate for beginners than other options.

Happy Planting!