Deep Water Culture Hydroponics
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Setting Up Deep Water Culture Hydroponics System

Deep water culture is a hydroponic farming technique where plants’ roots are suspended in the nutrient and oxygen rich water solution. This is the most popular hydroponic system for beginners and for classroom instructional purposes due to its technical simplicity.

DWC hydroponic farming system basically consists of plants whose roots are encased in a grow pot that is suspended from a lid with the roots hanging into the nutrient solution in the reservoir container. An air pump is used to aerate the nutrient solution.

The diffused oxygen allows the plants’ roots to take up maximum amounts of nutrients resulting into accelerated growth. The accelerated oxygenation of the roots improves water nutrient absorption which leads to accelerated cell growth. The efficient nutrient absorption lead to reduced amounts of growth fertilizers used compared to other systems.

Since the crops are constantly suspended in the nutrient solution, many plants won’t thrive and would die off because of overfeeding. The system is usually suitable for growing greens such as lettuce and other long-term crops such as cucumbers, peppers, eggplant, squash, and tomatoes with proper support.

With the nutrient solution in the reservoir stagnant, it is difficult to control the temperature and the solution tends to get hot fast hence posing a risk to the growing crops.

It is very easy to design a hydroponic deep water culture farming system from equipment which is readily available in the local farming store or online stores.

Materials required in Setting Up Deep water culture hydroponics (DWC) system

Reservoir container

This could be any water-tight container or an old aquarium which is used to hold the nutrient solution. The container should be big enough to hold enough solution for the number of plants. The container should be light proof to prevent algae growth. This can be achieved by painting the container black. You should leave a transparent vertical line to act as nutrient solution level meter and to monitor root growth.

Floating platform (Styrofoam)

The Styrofoam acts as the growing platform and a lid covering the surface of the solution from light penetration. The Styrofoam should be big to fit the surface of the reservoir tank.

Plastic grow cups

These are net cups that hold the plants on the floating platform. It’s recommended to use tapered cups to prevent them from falling into the solution.

Grow medium

Growing medium used include rock wool, vermiculite or perlite. In addition to supporting the young and delicate roots and stems, the medium performs wicking functions during early plant development to move nutrients to the higher parts of the roots.

Air pump and tubing

An air pump is extremely critical in the DWC system because the nutrient solution is stagnant hence the need for constant aeration. In DWC system, the air pump works 24/7 and slight glitch may cause detrimental effects on your crops. Aeration of the solution leads to bubbling in the solution which promotes even mix up of nutrients in the solution.

Air line/tubing is the connector between the external air pump and the submerged air stone. The size and length of the tubing depend on the pump size and the distance from the pump to the air stone respectively.

Air stone

This is a highly porous air diffuser that is submerged into the nutrient solution which evenly diffuses air into the solution for plant uptake. Air stones are available in all aquarium stores and the size depends on the size of your system and the size of the air pump.

Hydroponic nutrients

These are trace elements, fertilizers, and other growth supplements that are essential for normal plant development. These may either be the commercial premixed hydroponic fertilizers or homemade organic fertilizers.

Thermometer and ph testing kit

These are important in maintaining the best environment for optimal plant growth. Since the nutrient solution is covered the solution temperature tends to rise while ph varies widely. Water temperature and ph are important factors in proper plant growth.

Lighting

If you intend to set up your deep water culture hydroponic system indoors, it’s only important that you consider proper lighting for proper plant growth. Garden system size and the plant growth phase determine how much light fixtures and wattage is needed. The common types of lighting used include high-intensity discharge (HID) lamps during the growth phase and high-pressure sodium (HPS) during bloom to maximize yields.

Other tools required in preparing the hydroponic deep water culture (DWC) setup include sharp cutting tools, tape measures, and marker pencils.

How to set up deep water culture (DWC) hydroponic system

  • If the solution reservoir is transparent, paint it black to prevent light penetration. Leave a transparent vertical line for monitoring solution level.
  • Using a tape measure, note the dimensions of the reservoir. Using the measurements, cut the floater Styrofoam a quarter-inch smaller than the reservoir’s dimensions; this is to allow the floater to move up and down with the changing solution level.
  • Place the grower cups and using a pencil, trace the bottom of the pots on the Styrofoam. Using a sharp knife, cut out the holes on the Styrofoam. Ensure that the grower cups hang just below the Styrofoam but don’t fall through. On one edge of the Styrofoam cut out a hole for the air line.
  • Add the growing medium of your choice in the cups noting that the medium should not fall through the bottom. Place one plant in each of the grower cups.
  • Add water to the reservoir and mix the nutrient solution as per the instructions by the fertilizer manufacturer. Check the ph of the solution and adjust accordingly. It’s important to note that ph requirements vary from one crop to another.
  • Attach the air line from the air pump to the air stone and then place the air stone at the bottom of the nutrient reservoir. Switch on the pump to make sure the air stone is releasing air bubbles.
  • Place the floater Styrofoam on the surface of the nutrient solution. Place the grow cups to their designated holes on the Styrofoam platform.

Care and maintenance tips for DWC hydroponic farming systems

  • Constantly monitor the root growth. Once the root system is long and robust lower the solution level to prevent overfeeding.
  • Monitor the temperature. The recommended nutrition solution temperature is 62-68 oF (17-21oC). Too much heat reduces dissolved oxygen in the solution while low temperatures lower their metabolism.
  • Monitor dissolved oxygen level. You can monitor dissolved oxygen using an oxygen meter.
  • Checking the pH regularly helps in controlling growth in the various growth stages. For example, a pH of 6.0-6.3 is for vegetative growth while 5.7-5.9 is optimal for flowering and fruiting.
  • Check the nutrient solution regularly to prevent starving off the plants topping up when needed. It is recommended to refill with pure water during the first refill to prevent nutrient build up. During the second refill, the reservoir is drained and then refilled with fresh solution.

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