by Sunny Datko
What is Deep Water Culture (DWC)?
Deep Water Culture (DWC) is a hydroponic method of plant production by means of suspending the plant roots in a solution of nutrient rich, oxygenated water. With this system, the roots of the plants are submerged in the nutrient solution. The plant is then held in the proper position through the use of a net, which ensures that the top of the plant is not in the nutrient solution, only the roots. Deep Water Culture is sometimes referred to as direct water culture or Bubbleponics. Bubbleponics is a related method of plant production that involves a top-fed DWC system.
How Do Deep Water Culture (DWC) Systems Work?
Non-recirculating DWC systems use individual plastic buckets with the plant contained in a net pot suspended from the center of the lid and the roots suspended in the nutrient solution. This method provides more stability for the plant to remain with the roots in the nutrient solution. An air pump pushes air through an air stone, which oxygenates the nutrient solution. Once the plant has established a good root system, then it is advisable to lower the level of water in the bucket so that some of the roots can be allowed to hang in the air between the net pot and the water level. The majority of the roots live in the aerated deep water. As the roots are constantly submerged, it is crucial that the air pump is on 24 hours a day. If the pump is allowed to be off for any length of time, the roots will suffer.
What Are the Advantages of Deep Water Culture (DWC) Systems?
Highly Oxygenated – Plants exposed to greater levels of oxygen in and around their roots will subsequently enjoy unparalleled root development and prolific overall plant growth. This is because aerating the root zone radically improves water absorption, nutrient uptake and cell growth/activity within your plants.
Uses Less Fertilizer – Because the plant’s roots are suspended in the nutrient solution at all times, growers can use much less fertilizer than in other systems. We recommend using fertilizer at ¼ strength, often less.
Low Maintenance – DWC hydroponics systems are simple by design and require very little attention – the pumps are on all the time, so no timers or controllers are needed. There are no spray nozzles, return lines, feeder lines, or water pumps to clog, and no reservoirs or float valves to overflow or jam.
What Are the Drawbacks of Deep Water Culture (DWC) Systems?
Difficult to Maintain Water Temperature – Non-recirculating DWC systems are easily affected by high water temperatures and it can be very difficult to maintain temperatures below 70°F (21°C) inside the reservoir. The use of water chillers is recommended to achieve this optimal temperature range.
No Buffer – If the air pump fails, your plants will die. Given that roots are completely submerged in DWC, when the aeration is not constant they inevitably deteriorate very quickly – ultimately threatening the life of your plants.
Difficult to Check on Roots – Because the system is effectively just a bucket, the only way you can top up/pH adjust/test nutrients is to lift the whole plant up and out of the bucket. This sometimes proves difficult and hazardous to your plants when they are at full size.
Nutrient strength & pH Fluctuations – As your plants are literally growing in the reservoir, the pH and EC levels will vary greatly – even over the shortest periods of time. In multiple bucket systems each bucket must be tested individually, which can be a time-consuming process.