What is the Kratky Method?

2 min read

What is the Kratky Method?

What is the Kratky Method? 

Diagram of the Kratky method

The Kratky method is a hydroponics method invented by BA Kratky, a horticulturist at the University of Hawaii. His research work on passive hydroponics, drip irrigation, cultivation and management of the vegetable garden enabled him to develop this method.

This culture system is a simple and non-circulating hydroponic system, no need for a pump to circulate the nutrient solution, unlike the tide table for example. You are therefore no longer dependent on electricity thanks to this system.

In addition, it is extremely efficient because you only need to fill the tank with nutrient solution once for the entire culture.

According to BA Kratky, non-circulating (passive) hydroponic systems must follow a few basic rules:

  • The upper part of the root system should be exposed to moist air
  • The roots should not dry out
  • The lower part of the root system should be immersed in the nutrient solution
  • The level of the nutrient solution must remain the same or decrease over time, but it cannot be raised at the risk of “drowning” the roots

You can find his entire method on his article: Kratky, BA 2004. “A suspended pot, non-circulating hydroponic method”. Proceedings of the South Pacific Soilless Culture Conference , Acta Hort. 648. p. 83-89.

How does the Kratky method work?

The Kratky method is the simplest of all, perfect for beginners in hydroponics.

First of all the system consists of a tank and a lid. The plants are placed in a hydroponic basket which is then inserted into this lid. Nutrient solution is then added to the reservoir until it contacts the hydroponic basket.

As the plants grow, the water level decreases, leaving free space between the nutrient solution and the plant. This space is essential because it allows plants to receive the oxygen necessary for their growth. Indeed when the nutrient solution lowers, the roots in the air space thicken and branch out in order to capture more oxygen. This is why it is necessary not to raise the level of the nutrient solution in order to avoid damaging these new aerial roots.

The longer roots are therefore immersed in a nutrient solution and the shorter ones remain exposed to moist air.

Basil grown with the Kratky method

What kind of plants can you grow with the Kratky method?

With the Kratky method you can easily grow leafy greens, plants that have a fast growth rate and low nutrient requirements, such as lettuce, spinach, herbs. Jardin Futé has also tried growing lettuce with this method .

BA Kratky explains in his article how to grow lettuces. According to him, a 200g lettuce plant generally consumes only about 3 to 4L of nutrient solution adjusted to an EC of 1.5mS/cm3 for a 5-week culture.

It also explains how to grow cucumbers and tomatoes. He also wrote a second article on this subject: Kratky, BA, GT Maehira, RJ Cupples and CC Bernabe. 2005. “Non-circulating hydroponic methods for growing tomatoes”. proc. National Agricultural Plastics Congress 32:31-36 .

According to him, it is possible to grow vegetable plants that have higher water and nutrient needs. But it will be necessary to use larger tanks. Indeed, he discovered that he needed 30.5L of nutrient solution to produce 1Kg of tomatoes.

It’s your turn !

If you also want to try the Kratky method, find our tutorial “ How to make a simple hydroponic system ”.

Leave a Reply

Your email address will not be published.