As with building any other hydroponic system from scratch, everything can get pretty complicated from the start. The kratky hydroponic system is a growing method without the use of soil and its simplicity makes it perfect for beginners who want to get started in hydroponics.

The kratky method was actually developed by Dr. Bernard Kratky at the University of Hawaii and it’s a system of passive hydroponics without the need of pumps, electricity and mostly requires common household items. The kratky method is suitable for any scale and the most basic system that you can begin with, would require only a one gallon reservoir, mesh growing vessel, grow media, nutrient solution and a seed of your choice. As a general rule of thumb, you would need one gallon of nutrient solution for each plant you grow. This method of hydroponics is highly recommended for those who want to have a passive indoor hydroponics system and it’s easy to maintain.

As your plants mature and imbibe the nutrient solution, there will be an air space between the top of the nutrient solution and the bottom of the pot. This is mandatory in order to secure the vital oxygen for the roots. Usually in most hydroponic systems, the oxygen is supplied with an air stone or simply by the air that comes into contact with the cycled hydroponic nutrient solution. Once your nutrient solution is completely depleted, you will have to harvest the plants if they are one-time crop like greens or refill the solution reservoir if you are growing fruit-producing crops like cucumbers or tomatoes.

Let’s Begin With All The Stuff You Will Need

As mentioned above, the kratky method is an extremely simple hydroponics system which requires only a few things to get started. Down below, are the materials you would need to make your own Kratky passive hydroponics systems.

Plastic Container With a Lid – This is where all the action takes place and it will be used to both store the hydroponic nutrient solution and the net pot with your seedling.

Net Pot – The net pot is where you will put the growing medium and the crop seed.

Hydroponic Nutrient Solution – The nutrient solution is what keeps your plants fed and can be usually found online or at your local store.

Growing Medium – Choosing which growing medium you are going to use is up to you but i would personally recommend using clay pebbles.

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How To Assemble

Let’s first start with setting up the plastic tank, i would highly recommend using plastic buckets for your hydroponic system with a lid. After that you will have to cut a hole on the lid for the net pot. In order to do that, first measure the circumference of the net pot and cut one out accordingly by using a sharp knife. Then test it out and see if the net pot fits perfectly in the opening.

Make sure the net pot fits in the opening only up to its lid so the net pot doesn’t fall through the bucket lid. At last snug the net pot in place so it’s not entirely dunked into the hydroponic nutrient solution. Once you have completed all of the steps above, you can proceed to setting up your net pot.

As a rule of thumb, most of the time it’s better to first germinate your crop in a seedbed and then transfer it to your kratky system. This practice is being done even by commercial hydroponic growers. Once your seeds have germinated sufficiently enough, it’s time to set move them to your hydroponic system. All you have to do it simply fill your net pot with growing medium and now you can transfer the crop seeds into your hydroponic system.

After you’ve done that, now is time to prepare the nutrient solution and fill it in the bucket. If you purchased a ready-made nutrient solution, all you have to do is to make sure that the ration between nutrient powder and water is as shown in the instructions on the mix. Also always check the exact measure of your container / bucket before preparing the nutrient solution to ensure perfect ratio between water and nutrients.

If you add too much nutrient mix to the hydroponic solution, this might create a toxic solution with high pH and salt. And the same is true if you underdose the solution which will prevent your plant from getting the right amount of nutrients it needs. Now proceed with filling your bucket all the way up near the brim, but make sure to leave a little space for oxygen. After that, simply place the lid with the net pot on top and fix the lid.

What are the Pros and Cons of the Kratky Method?

With every hydroponic system, there will be always pros and cons to using the Kratky method. Being easy to assemble and operate makes it one of the go-to systems for both beginners and commercial growers alike. It can also be used for demonstration of hydroponics for businesses and school projects.

One of the main drawbacks in using the Kratky method is the difficulty in growing any long-term crops and root vegetables in a Kratky system. It’s also mostly conducive for leaf and lettuce crops. The method should be started with only the intent to grow leafy greens even though some growers have succeed in growing crops like peppers or cucurbits with the Kratky system, it’s just not worth the hassle.

Also if the reservoir is not checked regularly, the stagnant water can become a breeding ground for algae and many other pests. Having the bucket painted in solid color like black will help reduce the chance of getting pests as it prevents light from getting in. The reservoir also should be checked periodically for insect larvae and the pH measured every 4-5 days to ensure the required level of pH.