Kratky vs. DWC: Comparing the Hydroponic Systems


Hydroponic systems make growing plants at home more efficient, and there is none more simple than the Kratky method. While very similar to the Deep Water Culture system, it uses less equipment and requires less maintenance. It is an effective, low-cost growing solution that can work in just about any space. Choosing a method to use is the most difficult part, and it all comes down to the needs of your plants and space. 

The Kratky Method

The Kratky method is a simple hydroponic setup that utilizes the nutrient-seeking qualities of a plant’s root system to allow for passive and self-sustaining growth. This is a simple and generally hands-off method because it requires only a reservoir of nutrient-rich water and the seedling you wish to grow. When assembling a Kratky system, the plant is placed at the top of the reservoir suspended just above the nutrient solution, which attracts the root system downward toward the nutrients. As the roots drink from the reservoir and the water level drops, a gap is created, allowing the root system to breathe while still being partially submerged. The plant receives everything it needs to grow on its own without the need for soil or oxygenation equipment. 

Deep Water Culture

Another popular hydroponic method is the Deep Water Culture system, or DWC. This method is similar in setup to the Kratky method, but requires the plant roots to be fully submerged in water, utilizing air pumps and air stones to oxygenate the root system. As the root system is submerged, it will have immediate access to as much water and nutrients as it needs while the air stone placed at the bottom of the reservoir provides oxygen. This method requires additional equipment and maintenance, but as a result, the growing conditions can be more precise. 

The Basic Needs of a Plant

Of course, neither of these hydroponic methods would have any merit if they didn’t fulfill the needs of a growing plant. Providing the right amounts of light, water, nutrients and air is key to growing healthy plants. Both the DWC system and Kratky method can easily meet these needs. With light provided by the sun or an indoor grow light, and water and nutrients readily available within the reservoir, the only difference between these methods is how the roots receive oxygen. In traditional growing soil, there are plenty of air gaps to allow oxygen to reach the root system. Hydroponic methods use only water as a growing medium, so air must be provided to the root system in some other way. 

Since the Kratky method relies on an air gap in the reservoir for the roots to breathe, there is no additional equipment required to grow the plant. This is truly a set-it-and-forget-it method of growing. As the roots expand downward, they will continue to stay partially submerged in the nutrient water solution while an air gap is created between the water level and the top of the root system. This gap creates an ideal “breathing space” for the root system to receive oxygen. 

In a DWC system, air must be provided externally through an air pump and air stone because the root system is fully submerged in water. The airstone releases bubbles into the reservoir which interact with the root system, providing oxygen and allowing the plant to better absorb water and nutrients. 

Pros and Cons of Each System

Deciding between a hydroponic method can be tough, especially when considering these two systems. They are both very similar in setup and require little-to-no maintenance, so which one is actually better? To answer this question, it is best to consider where you will implement your hydroponic system and the kind of plants you wish to grow. 

The Kratky method requires no electricity if light is provided by the sun, so it is an excellent choice for off-grid growers looking for a self-sustaining hydroponic system. It is also an excellent beginner method because there is almost nothing to maintain. A plant can be left to grow in the reservoir from seed to harvest without the need for more water or nutrients. This reveals some drawbacks though, as plants with longer lifetimes do not grow as well in a Kratky system. Plants that take multiple months to bring to harvest require more maintenance, as the water and nutrient levels may need adjustment over time. Because this method is generally self-sustaining, it is also less precise compared to other methods and not ideal for all plants. The Kratky system is best suited for lettuce and herbs, but feel free to experiment with other species!

A DWC system provides air through a pump and stone setup, so the amount of water is always constant throughout the lifetime of the plant. This requires more maintenance and constantly running equipment, but it results in more precise plant care. Because of this, the DWC system is better for a larger array of plant types. It can be easily set up in a modular system–with multiple growing reservoirs connected to a central air pump–so it is also great for growing on a larger scale. DWC is better suited than the Kratky method for large fruiting plants, such as tomatoes, peppers, and cucumbers.

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