What is Deep Water Culture (DWC) Hydroponics?

Hydroponics is a method of growing plants without soil where plants are fed using a nutrient solution. The plants are supported in various substrates such as rock wool, expanded clay aggregate, gravel, sand, or coir peat. Since most hydroponic methods employ some type of growing support these methods are often referred to as “soilless culture”, while water culture alone is true hydroponics.  In this post, we will explore what deep water culture hydroponics is all about and take a look at how the process works.

Deep water culture is both an easy and effective method of hydroponic gardening.

In deep water culture, plants are grown in containers full of nutrient solution.  These containers can be small 5 gallon buckets or larger tubs and tanks for commercial systems. The nutrient solution in which the plant roots are suspended is usually aerated with an electric pump, tubing, and airstone which help to diffuse the air into solution. Generally speaking, aerated solutions are required to prevent roots from drowning.  More exactly, roots require oxygen in air because they perform a metabolic process called aerobic cell respiration. Just remember, DWC is the practice of growing plants in aerated water. It’s considered by many to be the simplest form of hydroponics. If you are a beginner in the field of growing plants then a DWC system is for you. These hydroponic systems are cheap and simple for DIYers to setup.

Plants are grown in slotted net pots suspended in holes cut in the lid of the reservoir.  Larger systems use a flotation raft instead of a simple lid. Reservoir size can be increased as plant size increases.  A single reservoir can be dedicated to an individual plant or many plants.  A large scale “raft” deep water culture system is shown below.

hydroponics deep water culture
A large commercial deep water culture system. In DWC, growth rates and yields can be astounding.

Which water level is best?

A well-hydrated plant typically grows incredibly fast and growers can manipulate water and nutrients levels in the root zone to decrease vegetative times by 15 to 25%. This decrease can trigger plant responses such as essential oil production, flowering, and fruiting. For instance, a dryer root zone can cause basil plants to increase their essential oil production. Whereas, a wetter root zone can cause plants to increase their photosynthetic rates by focusing on larger vegetative leaf production.

Choosing the Best Crops for Deep Water Culture

Are there any specific plants that DWC suits best? Here’s a list of potential crops for first-time growers.

Crop Growth Rates
Basil 8–10 weeks from seed
Lettuce 5–6 weeks from seed
Okra 7–9 weeks from seed
Kale 5–6 weeks from seed
Collard Greens 7–8 weeks from seed
Sorrel 4–6 weeks from seed
Chard 4–5 weeks from seed
Bok Choy 8–11 weeks from seed
Tomatoes 8 -10 weeks

Pros of Deep Water Culture:

  • Great for fast-growing plants
  • Flexible plant container sizes
  • Allows for larger root mass
  • Efficient use of water
  • Fewer plants with larger yield
  • Cost-effective to build and requires few parts

Cons of Deep Water Culture:

  • A chiller will likely be needed to cool the reservoir
  • Plants can be prone to root diseases
  • pH fluctuation may occur and requires periodic monitoring


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