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.

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.

Read also: Low-Cost Hydroponic Technology: Drawing the Line Between Cost and Function

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.

How the Kratky Method Works

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.

Purpose of the Lid

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: The Top 7 Mistakes Made By Hydroponic Growers

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 Project for Kids and Adults Alike

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.

Check out Low-Maintenance Hydroponics: Self-Watering Containers for more hydroponic gardening tips.