What is Deep Water Culture (DWC) ?

In the vast and ever-expanding world of hydroponic growing, few hydro systems produce consistently effective results as Deep Water Culture, or DWC, systems. A simple concept and setup, DWC offers an array of benefits that other systems simply cannot. Resulting in strong, unbound root systems, rapid growth, and increased yields, Deep Water Culture is a favourite among seasoned veterans and novice beginners, both for its ease of use and potential for abundant harvests.

What is Deep Water Culture?

In its most basic form, a Deep Water Culture system is a self-contained soilless grow system that suspends a plant’s roots in an oxygenated nutrient solution. Because the plant’s roots are not inhibited by the typical growing medium, such as soil or coco coir, and instead dangle into the oxygen-rich nutrient solution, micro and macronutrients are much more readily available for uptake. The result is a faster-growing, denser root system, leading to stronger plants with greater potency and higher yield. The internet is teeming with pictures of cannabis growers proudly displaying massive, wild root structures developed in DWC systems.

Often a single bucket or bucket system connected to a reservoir, DWC systems are vastly popular for their effectiveness, ease of use, and simple setup. Complete Deep Water Culture hydroponics systems can be purchased ready-to-go out-of-the-box, but many growers prefer to design and construct their own DIY bucket system. Though the design may initially appear complicated, its simplicity is actually one of its significant advantages.

How Does DWC Work?

Like most hydroponics, Deep Water Culture systems employ a pH-balanced, aerated nutrient solution to supply plants with their nutritional needs. The effectiveness of DWC growing results from the introduction of significant amounts of dissolved oxygen into the nutrient solution through an air pump and air stone. This constant aeration of the nutrient solution makes it possible for your plants to absorb massive amounts of oxygen, spurring on much faster growth. Some growers have reported that their vegetative period was cut in half after switching to DWC!

In a DWC system, plants are suspended in a soilless growing medium (usually hydroton pebbles or Rockwool cubes) and held in a net cup, allowing the roots to hang down into the oxygenated nutrient solution below. As a result, roots will not need to actively seek out nutrients from the medium, leaving them to develop freely and create a large root mass that will continuously feed around the clock.

DWC Setup

The beauty of the Deep Water Culture system is that it can be expanded to accommodate as large of a grow as necessary. Whether you’re growing in a single DWC bucket or an elaborate multi-bucket orientation, the necessary elements will remain the same:

Pots: In a single system, a bucket can act as both pot and reservoir; in multi-plant setups, hydroponic nutrient solution is stored in a separate reservoir and channelled into individual pots or buckets. The pots should be impenetrable by light to avoid the growth of algae in the solution.

Net pots: Regardless of the size of your grow, your plants will be suspended in net pots from the lid of the container or bucket used. The holes in the net pot allow the roots to grow through and seek out the nutrient solution below.

Growing medium: Growers typically use expanded clay pellets with DWC systems, though some prefer Rockwool cubes. Whichever you choose, it is essential to ensure that the medium is of sufficient size to not fall through the net pot.

Nutrients: Because your plant’s roots will be essentially living in the nutrient solution, it is important to provide your plants with high-quality, accessible hydroponic nutrients. In multi-plant setups, poor quality nutrients may also result in gummed-up emitters and channels, depriving your plants of necessary water and nutrition.

Air pump and air stone: As with any hydroponic system, the nutrient solution must be aerated by a constant supply of air bubbles in order to prevent the growth of harmful bacteria and algae. This is even more important in DWC setups, as reservoirs may require changing less frequently. A good air pump and air stone will provide large amounts of oxygen to your nutrient solution, keeping it fresh and leaving nutrients readily-available for uptake by your plant’s roots.

In larger, multi-plant variations (known as recirculating deep water culture, or RDWC), nutrient solution is stored in a larger reservoir and carried to individual pots by water lines. Some growers choose to aerate only the nutrient solution supply in the reservoir, while others choose to oxygenate each pot with its own air stone. This is a matter of preference; either choice works well.

Comparing DWC

Other hydro setups, such as top feed drip systems or ebb and flow systems, rely on occasionally feeding or flooding of the roots, leaving them exposed to air for portions of the day; DWC systems, on the other hand, provide a plant’s roots with a constant supply of oxygenated, nutrient-rich water. In this way, DWC is similar to the Nutrient Film Technique (NFT), wherein nutrient solution is channelled to roots through a system of pumps and banked PVC pipe, though a DWC setup offers greater oxygenation of the nutrient solution while doing away with the need to run a water pump constantly.

It is often noted that DWC bears a striking resemblance to aeroponic or bubbleponic systems, wherein nutrient solution is sprayed directly onto a plant’s roots via emitters or an integrated drip system. While the two are conceptually similar to DWC, and some RDWC growers do employ emitters in their pots, the simplicity of the DWC system still makes it the more viable option.

Advantages of Deep Water Culture

Despite appearances, DWC systems are some of the most simple and thus provide several benefits:

Automation: Once automated with the use of timers, DWC systems are quite self-sufficient, requiring far less maintenance than other hydro setups. Growers often leave their DWC system unattended for up to 24 hours.

Over- and under-watering: Because the roots are constantly exposed to the nutrient solution, there is veritably no chance of over-or under-watering. This dramatically reduces the risk of drying out your plant or drowning the roots, essentially eliminating the issue of root rot that plagues many hydro growers. It is important, however, to monitor the nutrient concentration in your solution to avoid locking out specific nutrients.

Growing media: DWC systems use such a small amount of growing medium that many medium-related issues are abated by default. For example, the need to check the pH of your soil or coco coir is non-existent when growing with DWC. In addition, the use of hydroton clay pellets or rock wool as a growing media helps with pest control as well.

Pests: Because many pests lay their larvae in soil or other growing mediums, particularly coco coir, the elimination of the medium goes a long way toward preventing an infestation. While a properly-sealed grow environment is still necessary, you won’t be introducing gestating larvae with your growing medium.

Disadvantages of Deep Water Culture

Although by this point you are probably excited to rush out and start gardening with a DWC system, it’s important to understand some of the drawbacks as well:

Fluctuation: Small systems use small amounts of water, and a rapidly-growing cannabis plant can use lots of it. As a result, water levels, pH level, and nutrient levels can all fluctuate significantly.

Air pump: With a DWC system, it is necessary to run an air pump constantly, which some growers consider an inconvenience due to the noise and increased energy costs. Fortunately, growers can acquire highly efficient pumps that run quietly. A NFT setup, by contrast, requires a water pump to remain permanently on, while nearly all hydroponic setups require oxygenation of the nutrient solution.

Flushing: Because there is no grow medium, it can be more difficult to flush your plant’s roots at the end of your grow or should you encounter nutrient lockout. Flushing in a DWC system will require multiple changes of the reservoir and careful, consistent monitoring of pH and PPM levels in the water.

As with all hydroponic systems, Deep Water Culture setups have both advantages and drawbacks. In this case, the benefits far outweigh the drawbacks, making DWC a viable option for growers at any stage of their journey. The easy set-up and maintenance of a DWC system makes it particularly well-suited for novice and beginner growers who are interested in growing hydroponically.