How Often To Add Nutrients To Deep Water Culture?

If you want to venture into hydroponic farming, you need to take care of the water system. One of the best hydroponics gardening projects is the deep water culture system.

It is among the recommended hydroponics projects that ensure your plants are healthy.

For you to ensure the system is healthy, you need to care of three things.

  1. Ensure the solution has appropriate nutrients.
  2. Ensure the solution has the accurate pH levels.
  3. Ensure that the water you are using for the hydroponic system is consistently healthy.

The frequency of changing the hydroponic water is key to keeping the plants healthy. However, even more important is how you change it.

We will highlight different aspects that will be helpful to learn concerning managing the water and nutrients in your system. 

What is Deep Water Culture (DWC)?

Deep water culture (DWC) is the purest form of a hydroponic system where plants are suspended in a solution comprising of nutrient-rich and oxygenated water.

DWC systems are straightforward.

In DWC, plants are only continuously watered unlike other hydroponic techniques such as Aeroponics, Drip system and Ebb & Flow.

The DWC system only requires a container, pump, a lid, and a net pot.

The purpose of the requirements, for instance, the container is used to hold the water and nutrient solution; the lid is to offer support to plants growing in the net pot; then, the roots grow into the nutrient solution in the container.

Finally, the reservoir container that holds the plants should contain enough water because more water provides stability in the nutrient solution, hence requiring less monitoring and maintenance.

Methods of aeration in Deep Water Culture

Aeration in deep water culture is done mainly in two ways;

  • Air bubbles

In the DWC system, airstone and air pump are used to provide air bubbles to the nutrient solution.

An airstone is a container with a material that resembles rocks, with small holes that provide small bubbles that rise on top of the water.

An air pump is joined to the air stone to offer the air volume.

Aeration provided depends on the size of the air bubbles, where the small bubbles provide excellent aeration for the solution, while large bubbles provide poor aeration.

Well, aeration is as a result of air bubbles having more contact surface with the water.

The contact between the water and air bubbles substitutes the dissolved oxygen that the roots absorb.

  • Falling water

The falling water is the second aeration method in the DWC.

Falling water is achieved through surface agitation formed as a result of the falling water splashing.

For the falling water method, the amount of falling water plays a vital role.

The higher the volume of water, the more the falling force, and with more potent force, the deeper the agitation with more dissolved oxygen there is and vice versa.

This method is more prevalent in commercial DWC because of the amount of water used.

What type of nutrients work in Deep Water Culture?

Mineral-based nutrients perform very well in the deep water systems.

According to hydroponic experts, growers should consider using nutrients that are in their organic forms with balanced mineral rates, specifically for DWC purposes.

Experts have strongly advised the use of nutrients that are well safeguarded and stimulates the pH levels and the stability of the solution.

What is the specific pH in Deep Water Culture?

The suggested pH level for the DWC system ranges from 5.5 to 6.5 for all the plants but profoundly depends on the plants grown and the growth stage.

For instance, vegetative plants in a vegetative stage will require the upper range of the pH levels when vegetating, flowering, or fruiting.

In contrast, other plants in the flowering phase will require lower pH levels.

These specific vegetative and flower phases show the pH ranges; this ensures that the minerals need for each growth phase are available.

What should ppm and EC be in Deep Water Culture?

For the ppm and EC in the DWC system should be on the low sides. Low amounts of ppm are required when plants are fresh.

For EC, low amounts are also required to promote high water intake into the plant’s tissue.

The level of water intake taken by plants influences the rate of plant metabolism and nutrient transport.

With high levels of water intake, there is an increase in the rate of metabolism and faster nutrient transport.

As the plant matures, the levels of the two variables (PPM and EC) can be adjusted.

Deep water culture plants absorb high amounts of water as compared to nutrients, so when nutrient solution the DWC decreases, the amount of nutrient concentration increases to a high level, which might be harmful to the plants.

How often should nutrient solution be replaced?

The nutrient solution in a deep-water culture system can last between two to three weeks (14-21 days).

The number of days purely depends on the size and growth phase of the plant and the volume nutrient solution in the system.

After two weeks, a 50% nutrient solution might be added to the system as a routine of adding nutrients instead of disposing of the existing nutrient solution from the system and adding a new batch.

However, if the solution’s pH levels decrease or increase beyond the recommended range, then a complete change of the nutrient solution might be necessary.

What is the best temperature for the nutrient solution?

Temperature is a significant challenge farmers face when using DWC.

The pump causes the heat in the system and also the growing area heats up once in a while increases the temperature.

Hydroponic experts advise growers to keep the temperatures moderate because of too warm decreases the oxygen levels while too cold hinders the plants’ growth.

Appropriate temperatures range from 170C-200C. Temperatures above 210C are believed to dissolve oxygen in the system while temperatures below 160C tend to drag the plants’ metabolism.

Plants tend to react to temperature shock during the temperature fluctuation process as they think it is a season change.

Many growers have taken the lead on studying the nutrient solution temperature, depending on the growth phase their plants are in.

For example, most growers tend to decrease the amount of nutrient solution almost at the end of the flowering stage to give room to the ripening process.

What temperature should my Deep Water Culture water be?

In science, water temperature and plant growth have a deep-rooted relationship.

However, the control of temperature is done to attain the ideal environmental conditions for plant development.

Water temperature for different plants fluctuates among species.

In a DWC, the nutrient solution temperature influences essential variables such as the plant’s metabolic processes and oxygen availability.

When high temperatures are experienced, the rate of plant metabolism also increases.

Therefore, establishing the perfect water temperature for deep water culture is mainly reliant on the usage of the plant oxygen and the rate of metabolism.

However, for commercial plants grown in the DWC, the temperature ranges between 150C to 300C.

For the DWC system to attain normal results, the water temperatures should be optimum at all times.

Experts have come up with various ways to control water temperatures in such systems.

Here are a few ways on how to control water temperature in a deep-water culture system;

  1. Insulation of the DWC system

The insulating material can be used to cover the system; this will ensure that temperatures inside the system are kept cool.

Insulation will safeguard the system from the heat generated from the pump hence maintaining cool surroundings in the DWC.

Insulation can be achieved mainly by painting the exposed containers white and keeping them away from direct light.

  1. Investing in a water chiller

A water chiller is an efficient method that reflects away unwanted temperature prickles in the DWC system.

Growers with very large or multiple systems are advised to purchase a water chiller because its function will reduce human labor hence reducing the amount of expenses to be incurred.

Most of the time, the temperature taps on the chiller will sense and adjust the cooling temp providing conducive surroundings for plant growth and development.

  1. Use of temperature fans

Temperature fans are mainly used for cooling purposes.

The fans are used to cool the system by controlling the amount of heat originating from the system.

Water cooling fans have their advantages when in use because they are easily accessible; however, the fans tend to increase the humidity levels in the system.

  1. Use a temperature regulator

A temperature regulator is usually set at a certain level and observers the real system temperature.

Once the system overheats, cold fluid is released from the regulator to cool the system coil, and when the regulator’s temperature is reached, the valve closes, stopping the fluid from flowing.

This is one of the most effective methods to use when trying to cool the DWC system without disrupting other functions.

  1. Locate the indoor system away from the heat

The indoor DWC system should be placed away from the heat.

Putting it in a very cool place assists in minimizing the heat transfer keeping the water temperature at standard levels.


From what we have seem above you too can easily start your own hydroponic system.

If this seem like a tall order for you them buy an indoor hydroponic kit.

What are you waiting for? Get started today.