The Kratky Method: A Simple & Fun Way to Grow Hydroponically

By Shannon McKee
Published: April 24, 2020 | Last updated: May 26, 2021 07:47:51
Key Takeaways

Hydroponic systems can be complex. For many growers, constantly tinkering with their systems is part of the appeal. But sometimes an easy, simple way of growing can provide a nice break. The Kratky Method provides a fun, hands-off way of growing hydroponically without tubes, pumps, and electricity. Shannon McKee tells us how it works.

Caption: Kratky method growing using plastic container and net pots Source: vm2002/Shutterstock

You love container gardening. It offers an easy way to get fresh vegetables and fruits in a small space without a lot of hassle. Hydroponic gardening is another great method of gardening, but can often take up a lot of space, have energy requirements, and can be complex depending on the system.

What if I told you there was a way to combine your love of containers with hydroponic gardening? The Kratky Method is a way of hydroponically growing your plants in a container without needing electricity, air stones, pumps, or anything else. This means that the Kratky Method is a passive hydroponics system.

This method was developed by University of Hawaii horticulturalist Bernard A. Kratky, and is perfect for someone that wants to grow indoors without having to get wrapped up in a more involved hydroponic system.


How to Set Up a Kratky Hydroponic System

Illustration demonstrating the Kratky methodIllustration demonstrating the Kratky method

This passive hydroponic technique involves growing plants suspended above a reservoir of nutrient-rich water. The Kratky method is ideal for small-scale and low-maintenance gardening, making it perfect for home growers. The steps below will guide you through the process of setting up a Kratky hydroponic system so you can start growing your own plants in no time.

Items Needed:
• Seed of choice
• Container with lid that can be cut
• Water
Nutrient solution
• A pH kit
Net pot
• Growing medium, like rock wool


You’ll want to find a container that will be large enough for your purpose. A tomato plant will need a larger container, such as a pail, a Styrofoam cooler, or even a plastic food-grade storage container. A smaller plant will require a smaller container, like a large coffee can or similar sized container for growing a head of lettuce.

To prepare, fill the container with the water and the nutrient solution. You’ll want to test the pH to make sure that the water is ideal for the type of plant you’re growing in it.

Next, prepare the container. You’ll need to put a hole in the lid of the container that’s big enough for your net pot to sit in. Plant your seed in the growing medium in the net pot, and watch your plant grow. (Read also: The Dutch Bucket Hydro System and How it Works)

How the Kratky Method Works

Hydroponic plant growing in a water bottle and mason jar showing roots and basket using the Kratky methodHydroponic plant growing in a water bottle and mason jar showing roots and basket using the Kratky method. Source: Shutterstock

As your seedling draws water up into the net pot, the water level in your container will start to decrease. This lower water level will then fill with air providing oxygen for the roots of the plant.

When the water in the container is gone, it is time to harvest the plant. If you want to keep the plant going longer, you can just lift the lid and add the water and mineral solution.

The lid is a vital portion of using the Kratky Method. First, it creates a place for the moist air to circulate among the plant roots underneath it. Second, it helps to support the plant itself above the water level.

This is beneficial because the lack of direct contact between the water and the plants reduce the risk of some plant diseases that can occur between the root and leaf at the collar zone.

One final benefit is that this space will increase the aeration in the container, which allows for the heat to dissipate from the water. (Read also: A Gravity-Fed Home Hydroponic Garden System)


What You Can Grow With the Kratky Method

Some of the most popular plants to grow using the Kratky Method are a wide variety of lettuce, spinach, herbs, and even tomatoes. Basically, any plant that grows above ground is fair game to be grown in this method.

Larger plants are not as hands-off as the smaller plants, especially if you’re using a container that is not big enough. Larger plants will need to have the water and mineral solution stay about two inches deep to give the roots access to it while keeping lots of oxygen in the system to support a larger plant. This is something that you’ll need to keep an eye on in the case of plants like tomatoes or peppers.

A fun project using this to help kids understand how a plant grows is to set up a windowsill herb garden. Instead of using an opaque material for growing the plant, use a glass mason jar. This will help them see how the seed turns into a seedling, which then turns into a full-grown plant.

You may not be able to use a lid for this, but you could find a net pot that fills the entire lid where the growing material can act in the same capacity as a lid in the larger version. Think of how nice it would be to always have access to a sprig of basil or another fresh herb all year long.

You may have never heard of the Kratky Method before now, but if you’re looking for a simple and easy way to grow plants hydroponically, look no further. This is a no-fuss, no-muss method of combining all the things you love about container gardening with a hydroponic garden. (Read also: How to Build a DWC (Deep Water Culture) System at Home)


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Written by Shannon McKee | Freelance Writer, Gardener

Profile Picture of Shannon McKee

Shannon McKee lives in Ohio and has been a freelance writer for several years now, including on her blog, Nicknamed by loved ones a garden hoarder over the past few years, she grows a wide variety of plants in her urban garden.

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