The Kratky Method: A Brief Overview


Growing plants and vegetables hydroponically may just be easier than it seems—thanks to the Kratky method! 

Hydroponics is a method of horticulture that does not require soil – instead, the plants are grown in a nutrient-filled aqueous solution. In the past, hydroponics required power and expensive startup costs to operate. Recently, a passive, simpler approach to hydroponics has been devise. By removing much of the startup costs and power requirements, the “Kratky” method has made it more accessible for someone to start growing plants hydroponically at home!

The Kratky method was discovered and tested by B. A. Kratky, a professor at the University of Hawaii. Many see the Kratky method as a version of “Deep Water Culture”, but minus the pump. In Deep Water Culture, or DWC, plants are suspended in a water solution and a pump is constantly aerating the water. The Kratky hydroponics system replaces the pump with an “air pocket” that gives the plant’s roots all of the oxygen they need.

The Diet of a Plant

As you may know, plants require oxygen, water, and light to survive. In the Kratky method, plants are suspended in a bucket of water, which provides for all of their H20 needs. The light requirements can be met one of two ways – passive or powered. If growing outdoors or in a greenhouse, passive sunlight can be used. Otherwise, you will need grow lights to sustain your plants.

With water and light satisfied, the only problem left to solve is the oxygen requirement. With no pump aerating the roots, how do the plants in the Kratky hydroponics system receive their oxygen? Well, as the water level drops in the Kratky bucket, more and more airspace is left behind. This air pocket is fed upon by the plant’s upper, exposed roots, while the longer roots continue to feed on the water and nutrients below.

For a plant to reach its full potential, it also needs a combination of micro and macro-nutrients. These either come in the form of mineral salts or liquid solutions that are mixed into the Kratky growing container.

What Plants Work Best?

The Kratky method can be used to grow almost anything, but it works best when used with fast-growing plants, such as herbs, kale, spinach, lettuce, and other greens. These plants will finish growing before the container runs out of water, so it will be a truly “set it and forget it” type of passive growing system.

When growing larger plants that fruit or flower, you may have to refill the water reservoir from time to time, depending on the size of bucket used and other factors. When growing these heavy feeding plants, you may also need to check nutrient and pH levels in the water, leading to more complexity in your system. 

Is Kratky Right for Me?

If you are interested in trying out a simple, easy way to grow plants hydroponically, then yes, the Kratky Method is for you! No power requirements and low start-up costs means anyone, anywhere can start growing their own food today! If you are a large-scale, commercial grower, then a more sophisticated growing system may be better for you. Check out our next article on how to make your own Kratky Hydroponics Bucket!

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