Introducing The Simple Way To Kratky Method For Beginners

Kratky Method

So many people cannot afford the luxury of an AeroGarden, but did you know there are alternatives to growing your salad leaves and vegetables? Well, there is a much simpler way. Dr Bernard Kratky designed the Kratky hydroponics method at the University of Hawaii has created a simple design.

I will show how introducing the simple way to Kratky Method for beginners will simplify the process to learn how the system works, what you can grow successful using the equipment found within your home, how to set up your unit and the nutrient requirements needed for healthy plants and the pros and cons of the Kratky method.

Learning About the Kratky Method a passive hydroponic system

Kratky hydroponics growing system is a passive hydroponics idea that does not need electricity or aerating pumps. Still, everyday household items make it an ideal way to start learning about hydroponic gardening.

Kratky Method: how does it work?

How the Kratky Method works are best described as taking your seedlings and placing them into your Hydroponic growing medium inside a net cup and placing it in the hole where the cup touches the nutrient water inside the container.

Points to Note

  • Ensure there is a gap between the lid and nutrient solution, so the upper part of the root system is exposed to humid air
  • Do not allow the rots to dry out
  • The lower parts of the root system should reach the water to allow the roots to obtain water and nutrients
  • Do not allow the roots to drown in the water. Do not raise the water levels; they can remain the same or lower.
  • Keep an eye on temperature fluctuations
A Model Suspended Pot, Non-Circulating Hydroponic System after the Nutrient the solution has dropped below the seedling Container
A Model Suspended Pot, Non-Circulating Hydroponic System after the Nutrient the solution has dropped below the seedling Container

Source: International Journal of Agricultural Science and Research (IJASR) ISSN (P): 2250-0057; ISSN (E): 2321-0087 Vol. 7, Issue 5, Oct 2017, 547-556 Trans Stellar Journal Publications.

What can you grow with Kratky Method?

The best plants to grow using the Kratky Method is a leafy green that have a fast-growing rate plants includes

  • Spinach was tested in the Study of Hydroponic Systems. Their Variations in 2017 using coco peats and 2-3 spinach seeds were placed ½ inch deep inside the basket under an ideal controlled temperature of 22-26 Degrees Celcius. The seeds in the ambient temperature and humidity levels inside the container can sprout in 2 days in the dark. The spinach was tested, completed under various conditions, methods and using a range of materials. The end conclusion shows that spinach can be grown using the Kratky method with successful results.
  • Herbs love an ideal temperature of 65-70 degrees Fahrenheit, a much warmer temperature than LettuceLettuce. Basil, mint, dill, cilantro, sage and thyme are suitable for these systems.
  • All types of lettuces can be grown—Lettuce in the Three Non-Circulating Hydroponic Methods for Growing Lettuce by B.A. Kratky. was tested with excellent results. Lettuce loves cool temperatures.
  • Kale
  • Bok Chou
  • Chard
  • Collard Greens
  • Endive

Also, other plants that can be grown using this method but will need a bigger tub or container are

  • Tomatoes can be grown relatively quickly, but a larger container is needed. A container such as a 20 litre one with a lid will work well. It will allow plenty of root space and will need topping up with nutrient water. 
  • Strawberries are pretty easy to grow; this method is beneficial to the fruit because they are grown in a dirt-free environment and will produce lots of fruit all year.

Plants that are not successful with the Kratky Method

  • Broccoli
  • Brussel Sprouts
  • Peppers
  • Tomatoes, some people have had successfully grown tomatoes, and others haven’t had any success.
  • Rosemary
  • Chives
  • Lavender

Kratky hydroponics Equipment

  • 4-litre container to hold water
  • Nutrient solution
  • Growing vessel (mesh)
  • Growing medium such as rock wool, sphagnum moss or coconut coir
  • A seed
  • An excellent indoor light source such as LED lights with red, blue and white colours, also known as grow lights.

Each seedling will need at least 18 Litres (one gallon) of a liquid solution.

As the roots start to grow, the seedling will begin to mature. The roots grow in the liquid nutrient solution, and between the container and the bottom of the growing vessel, the roots will grow and branch laterally and absorb oxygen from the air; they are also known as “oxygen roots”.

How to set up your Kratky Hydroponics System

  • Get a container that can be sealed, such as a 20-litre bucket with a lid
  • Drill a hole in the cover that will be large enough for one mesh growing pot or drill one hole for each pot. Drill hole size is about 5 cm in diameter or larger
  • A recycled plant pot with holes drilled in the sides or poultry netting and wire.
  • Fill the container with water and add the measured nutrients required for growing your plants.
  • Test the water pH level to ensure that the solution is ideal for your seeds to grow. pH testing kits are available for purchase at your garden centre.
  • Fill the pots with perlite, rock wool or sphagnum moss and suspend the net cup above the water containing your nutrient solution.
  • Place one or two seeds into the mesh pot.

The root tips will grow and touch the reservoir. If you have added more than two seeds into each pot, you will need to thin down one seedling, preferably the strongest one.

Mason Jars can also be used

Using any kind of jar found in your kitchen cupboard can be used. So what do you need?

  • Quart-sized wide-mouth jars with bands
  • 7.6 cm (3 inches) net pots for each jar
  • Rockwool growing cubes
  • Clay pebbles
  • Nutrients
  • Seeds, e.g. Lettuce

The jar will need to be blocked out to stop light from entering the jar; doing this will prevent algae from forming. You can either use black spray paint, duct tape, washi tape or a light-blocking fabric made into a sleeve. If you use the material, you can slip the sleeve of the jar to check the roots and whether you need to add more nutrient solutions.

The steps to assembling your Mason Jars

  • Plant seeds in your Rockwool cubes
  • Prepare your jars and have them ready for when your seeds germinate
  • When the seedlings have roots that extend out of the bottom of the cube. You can transplant them to your glass jars.

Preparing you Jars

  • Wash the jars
  • Rinse your clay pebbles
  • Spray paint the outside of your jar black, or use what other method you have chosen
  • Add the net pot to your jar
  • To hold your jar in place, screw on the band
  • Fill the jar with water to 6mm (1/4) above the bottom of the net pot
  • Add nutrients
  • Add a thin layer of clay pebbles to the bottom of your net pot. 
  • Add the Rockwool growing cube containing your sprouted seedlings onto the pebbles
  • Add more pebbles and rock wool around and on top of the cube
  • Place your jar in a sunny location or place it under your LED light.
Seed germinated in peat
Germinated seedling Source Pexels

Are hydroponically grown plants good?

This is a debatable topic that is mostly based on opinions that I don’t always agree with, and some say plants grown this way will tend to have root structures stunted and that If you grow your plants in the garden soil, their roots have ample room to spread and grow. In addition, when you grow your plants using the hydroponic method, they are fed chemical fertilisers; therefore, the roots are overloaded with nutrients.

In my opinion, I have grown plants in water using a glass jar and an AeroGarden, and I have not had any issues with stunted root growth in any of my projects, only seeds failing to germinate.

In the second part of the topic regarding chemical fertilisers. Commercially grown or homegrown plants are often fed some chemical fertiliser to help the plants grow much healthier and stronger. Using home compost may be the only natural way for your plants to obtain nutrition. However, when it comes to the Kratky Method, they are grown in water, and as such, depending on the quality of your water, it most likely needs nutrients added to it; otherwise, your plants will die.

Fertiliser Recommendations for the Kratky hydroponic

Growing plants in hydroponics will need nutrients to grow strong and healthy; otherwise, they will die. 

Plants grown in the Kratky Method do not need a pump to circulate oxygen because the root system is more exposed.

Pros and Cons to the Kratky method


  • Easy to use
  • Low cost
  • Cheap to maintain
  • Maintenance is simple and easy
  • Ideal for newbies
  • Ideal for lettuces and spinach
  • Success is possible with tomatoes, peppers, and cucurbits


  • Unable to grow root vegetables
  • Not ideal for a large setup
  • Pests can be a problem
  • Not suitable for large or long plants
  • Stagnant water smell
  • Can be an ideal breeding ground for insects such as mosquitoes and algae

The best solution for the insects is to use a colour that does not let light inside the container. You will need to regularly check the water holding container for insect larvae and change the solution with a fresh mixture.

Harvesting your plants

As your plants grow, they will be ready for harvest. The nutritional water will probably need topping up. You can do this by adding water and nutrient solution.

In conclusion

The Kratky hydroponics design is simply ideal for beginners who are new to hydroponics. I have shown you the simplified process on how the system works, what you can grow successfully using the equipment found within your home, how to set up your unit and the nutrient requirements needed for healthy plants.

If you would like to learn more about Growing Lettuce in a Hydrogarden click here to see my project.

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If you have any questions about this post’s content, please leave a comment below I would love to hear what you think about the article.

6 thoughts on “Introducing The Simple Way To Kratky Method For Beginners

  1. Christine says:

    The Kratky system seems easy enough, a great way to start this, and then in the future I can still get an Aerogarden. I have eaten veggies and fruits that were hydrophonically grown and they were tasty and delicious. I have some plants growing in the garden, but since I live in a harsh semi-desert climate, other plants will have to be grown indoors, and the Kratky method seems ideal for that.

    • Yvonne says:

      Hi Christine
      Thank you for responding to my post. I agree the Kratky method is ideal for anyone wanting to get started in hydroponics. We eat lettuces grown the hydroponics way, and we find them much nicer. For our hot sun, we protect our veggies with shade cloth in summer. It works a treat.
      All the best

  2. Matt Lin says:

    Hi Yvonne,

    The Kratky method is a good start for people who like a try without much budget. I like to know what nutrients that I need to add to the water for my Kratky system. Does it depend on the veggies I like to grow, and is it easy to find online?

    Thanks in advance,

    • Yvonne says:

      Hi Matt. Thank you for stopping by.
      The Kratky method is a great way to be introduced to growing your salad greens in water.

      When it comes to the veggies that you are attempting to grow, I would first take a water pH test, as water is different in many areas. Adjust the nutrients to suit your greens.

      You will find advice on the back of a bottle of liquid nutrients. You can buy fertiliser that is suited to Hydroponics.

      I have written the suggested recommendation in the post for measrements.

  3. Brianna Kraushaar says:

    I have heard of aero gardens but I had no idea you could create one of your own. This was a real eye opener!’
    I am not sure I like the thought of accidently growing mosquitos. Is there a way to prevent that from happening?

    • Yvonne says:

      I haven’t had an issue with mosquitos but if I did I would change the water and ensure any holes are covered with glad wrap or foil. If it still continues let me know.

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