Deep Water Culture for Beginners

The Pros & Cons Plus Step-by-Step Instructions

Deep water culture (DWC) is a straightforward hydroponic system that recirculates nutrients through one or more buckets in an interconnected system. Newbie growers may want to start with a single bucket, but this hydroponic system is incredibly easy to scale.

DWC systems are affordable, easy to troubleshoot, and manageable for even a beginner grower to master. So whether you plan on growing tomatoes, peppers, lettuce, or cannabis, you’ll want to start with recirculating DWC. 

What is Deep Water Culture Hydroponics?

A DWC system is a specific hydroponics setup (there are many) that grows plants in a “deep water” nutrient solution and nothing else. DWC is almost exclusively used for indoor operations and is a favorite among indoor cannabis cultivators. 

The simplest DWC design is a single bucket filled with nutrient-rich water. This is often called a Bubble Bucket. There is one plant per bucket, nested into the lid in a net pot. As this is a hydroponic system, there is no soil. Instead, each plant roots into Rockwool and clay pellets. 

Plants send roots down into the aerated nutrient solution, pulling all the oxygen, nutrients, and minerals it needs to thrive.

DWC systems are also called recirculating deep water cultures because a water pump continuously moves the water through the system to prevent stagnation. Air stones and an air pump aerate the nutrient solution, providing oxygen to the plant’s roots. Both recirculation and aeration also help to prevent algae growth and disease.

Pros of a DWC System for Beginners

Out of all the different designs for do-it-yourself hydroponic systems, DWC is one of the most popular, and for a good reason. The pros of this system are:

  • Cheap to set up and inexpensive to maintain
  • Faster growth and bigger yields compared to traditional soil-based systems
  • Lower nutrient costs

Cons of a DWC System for Beginners

However, that doesn’t mean it’s perfect. Beginners especially should know what frustrations they may face when they dive into the world of DWC. The most common issues are as follows:

  • Regulating fluctuating pH levels and water temperatures
  • Loud air pumps that are not as discreet as some growers would like
  • Electrical outages needing immediate attention

3 Different DWC Systems

Indoor growers love to experiment, which means there have been many evolutions of DWC systems over the years.

1. The Kratky Method

Often described as the most rudimentary type of DWC, the Kratky method is as simple as they come. A plant sits in a growing medium, with its roots dipping into a container of nutrient solution. The roots sit 50 percent in the solution, with the remaining 50 percent out in the air under the lid.

There is no additional reservoir, no air stone, and no air pump. Indoor grow lights aside, the Kratky method requires no electricity and is therefore sometimes called a passive hydroponics system.

The Kratky method isn’t ideal for most indoor growers, even beginners, because it is prone to failure. With no airstone and no recirculation, water stagnates. In addition, the system is prone to diseases like root rot and algae growth. 

deep water culture set up, grow lights, cannabis
Sample deep water culture system, posted by Hydroguy on Strainhunters

2. Recirculating Deep Water Culture (or RDWC, or DWC)

The most common DWC system is technically a recirculating deep water culture system. These systems use a pump and an air stone to recirculate the water throughout the system.

Unlike the Kratky method, the nutrient solution develops with the plant. As it recirculates, new nutrients must be added, and it’s always aerated. 

RDWC systems may also have a separate reservoir, sometimes called a control reservoir. The reservoir contains the pump and air stone and makes ongoing nutrient management easier without disturbing the plants.

3. The Bubble Bucket

The Bubble Bucket is a simplified DWC system. It contains all the same parts as a multi-plant system but condenses it into a single bucket. The airstone and pump recirculate the water in a closed, one-bucket ecosystem.

For newbie growers, a Bubble Bucket is the most accessible system to set up as there is no plumbing or tubing to worry about between buckets and no outside reservoir. Plus, you’ll only be managing one plant, not working with many.

How to Build a Recirculating Deep Water Culture System

Let’s walk through the setup of a basic RDWC system. Although you can have as many or as few plants within the system as you want, we’ll cover a system with four plants and one control reservoir.

You can also buy complete kits, which come all ready to go with everything you need to get started. Hydroponic kits make even a simple setup foolproof.

Components You’ll Need:

  • 4x 5-gallon buckets + one 5-gallon bucket for the reservoir
  • 4 x net pots
  • Inline pump
  • 1″ tubing
  • Tubing connectors (T and elbows)
  • Clay pellets
  • Seedlings/seeds
  • Rockwool

Tools You’ll Need:

  • Sandpaper
  • PVC cutters or clippers
  • Drill and spade of hole saw drill bits
  • RTV silicone
  • Measuring tape

Instructions for RDWC Set up:

  1. Sprout Seeds: Get started sprouting your seeds in Rockwool cubes. You’ll plant these into the hydroponic setup once they are between 10 to 14 days old.
  2. Lay Out and Measure: Based on the size of your grow tent or closet, place the buckets (including the reservoir) in the design you’ve decided on. There are many possible designs, but aim to make it as simple as possible: a straight line, a rectangle, or a “T” shape are a few options. Once you’ve got everything placed, replicate the design on paper and take accurate measurements for placement and tubing.
  3. Drill Tubing Holes and Airline Holes: Drill the necessary holes for the tubing into each bucket and the reservoir based on your design. Fittings should be as close to the bottom as possible. In a rectangular system, each bucket will need two holes. Clean up the hole edges with a bit of sandpaper, which will help get a proper seal. Drill an additional smaller hole near each bucket’s top lip (or in the lid) for the air stone tubing.
  4. Install Fittings: Based on your diagram, install fittings and rubber gaskets into each bucket hole. Seal the fittings with RTV sealant. Allow to harden.
  5. Cut and Install Tubing: Once again, your diagram and measurements will come in handy. Cut the tubing to the necessary sizes to connect each bucket, as well as to connect to the reservoir. Add any elbows for the corners or t-fittings as needed to create the layout you’ve planned. By this point, you should have all buckets connected in the shape you’ve drawn out. Connect to the reservoir. 
  6. Connect and Place Air Stones: Feed air stone tubing into each bucket lid, and connect the air stones to the bottom of each bucket. Hang the air pump from the ceiling. Hanging the pump helps reduce noise and vibration.
  7. Connect Inline Pump: Now, install the inline recirculating pump. It should be large enough to move the water through the system at least seven times an hour. 
  8. Add Water and Check for Leaks: Working five gallons at a time, add water into the reservoir. It will naturally move through the system to fill each bucket to the level desired. Check all connections closely for leaks as you go. Reseal as needed.
  9. Nutrient and pH Balance: It usually takes a few days to correct the pH levels and stabilize the water temperature. Monitor daily, especially after adding nutrients. Allow the system to run for a handful of days to ensure levels don’t fluctuate too wildly before adding plants.
  10. Add Plants: By this point, you should have seedlings ready for the DWC system. Insert the Rockwool cubes into the clay pellets in the net pots, and insert one into each bucket. 

Deep Water Culture, Perfect for Beginners

If you are going to set up a hydroponics system, deep water culture is the ideal starting place. It’s affordable, straightforward, and scalable. Cut your teeth on a Bubble Bucket, but you can expand into a multi-plant system as you learn the ropes.

With the number of plug-and-play hydroponic kits now available, plus the in-depth guidance available through forums like the HydroGuide community, you are guaranteed to succeed. 

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