How to Grow Cannabis Using the Kratky Method Of Hydroponics?

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Added 03 December 2021

Growing hydroponic cannabis isn’t rocket science. 

With a bit of patience and understanding, you can grow dank buds like some of the most experienced growers out there. 

Whether you want to switch to hydroponics or are just starting, you can grow amazing plants, provided you understand the science behind it all. 

Rather than aping others, it’s best to understand the plant and master the technique required to give you the best results. 

Hydroponics has several variants, and each one of them differs from one another. 

While you can grow cannabis with any variant, starting with the easiest one at first makes sense. 

In this article, we will explore one of the simplest hydroponics methods, called the Kratky method. Other techniques require energy, lots of space, pumps, and tubes to grow plants, but the Kratky method is a hands-off way of growing cannabis — a set-it-and-forget-it system. 

Sounds interesting, right? So, let’s get started — here’s a guide on growing cannabis using the Kratky method.

What is the Kratky method?

The Kratky Method

The Kratky method was introduced by BA Kratky, who was a student at the University of Huawei at the time. This method is very similar to DWC or Deep Water Culture — another hydroponic technique to grow plants; however, the Kratky process doesn’t require a pump to function. 

In addition, you don’t even have to make any changes to the reservoir’s nutrients! And, as if that’s not enough, it’s one of the cheapest systems because it doesn’t require special equipment. 

Here's a simple diary displaying the Kratky method from start to finish 

This low-maintenance hydroponic method to grow cannabis can set you free from the hustle of growing cannabis. All you have to do is:

  • Place a plant in a net pot
  • Fill the tank with nutrient solution
  • Place the net pot at the top of the reservoir
  • Harvest the buds when it’s all done!

I can almost hear you wondering whether this is too good to be true. Most beginners and even some experienced growers shy away from hydroponics because it all sounds so complicated. Soil is a little more forgiving where you get a chance to help your plants in distress, but hydroponics can be brutal at times. A small mistake in the pH can ruin things.  

Remember, you will need to maintain pH and other essential things even with Kratky, but it won’t be as complex as other methods. Not to mention that you won’t be spending as much money as well. 

To put it simply, this method works amazingly well if you’re planning to grow just a few plants. The system can survive on its own for a few weeks, but you may have to interfere at times to check the water levels and pH readings. 

How does the Kratky method work?

As mentioned already, it’s very similar to DWC, except that it doesn’t need other electronic devices or wicks and pumps. 

No matter what method you use, plants require water, oxygen, light, and nutrients to grow. While the system takes care of oxygen, you will have to supply both macro and micronutrients and light for the plants to grow to their maximum potential. 

The Kratky technique supplies all these essential ingredients easily with a little help from you:

1) Nutrients ‒ Just like other hydroponic systems, you will need to add the nutrients to the reservoir containing water.

2) Fill the net pot with the chosen growing media such as rockwool or clay pebbles, and insert the plant into the net pot.

3) Hang the net pot supported by a lid at the top of the container.

4) Do not submerge the roots entirely in water. There must be an air gap between the roots and the water, so the plant gets adequate oxygen.

Over time, as the plants continue to grow, the reservoir's water level decreases as the plants absorb it all, and you may have to intervene if the plants aren't ready to be harvested yet.

The Kratky method is so simple yet efficient because it provides water and oxygen effortlessly. As the cultivator, your job is to provide the lighting and the nutrients. Compared to other hydroponic techniques, this is the easiest and most efficient method with minimal interference.

In a nutshell, the plant roots absorb the water and pass the nutrients to the plant. Water depletion then creates air or oxygen for the plant to breathe in. 

And since cannabis is a fast-growing plant, they grow best in the Kratky hydroponic system — by the time the water gets absorbed, the plant is ready to harvest! 

What do you need for the Kratky method?

The Kratky method requires some basic tools such as:

  • Reservoir or container: The reservoir size depends on the size of the plant. Start with compact plants that are easy to maintain instead of jumping to growing monstrous plants on the first try. If you plan to grow a small plant, even a milk jar will work, but you will need bigger containers if you grow strains that tend to grow very big. In addition, your first project will give you an idea of the size for the next try. 
  • Lid: A plastic or styrofoam lid protects your plant from diseases, pests, and water from evaporating. Ensure you keep the lid closed at all times since it protects the plant from diseases and pests and prevents water evaporation. If you purchase a ready-made setup, you can buy the lid; however, if you’re setting up a DIY system (we will get to that later), a plastic or styrofoam lid will work just fine. The lid will also support the plant from collapsing as you hang it at the top. 
  • Net pots anchor the plant and are usually made from plastic mesh to promote drainage and circulate air.
  • Grow medium: Grow medium is placed within the net pots. You can use perlite, but I recommend hydroton or clay pebbles since perlite tends to seep through the net pots, making it very messy. Also, make sure you purchase pH-neutral grow media. 
  • Nutrient solution: A regular hydroponic nutrient solution mixed with water works best for the Kratky method to grow cannabis. Pro tip ‒ If liquid nutrients seem too expensive, you can purchase nutrient kits containing both macro and micronutrients and mix them according to the instructions on the label, making it a lot cheaper for you. 
  • pH control kit: The kit would contain the pH meter and other tools that help you identify and rectify the culture’s pH balance. In other words, you will need a solution that increases the pH (pH UP) and another solution that reduces the pH (pH DOWN) along with a pH meter. 

What steps should I follow?

The Kratky method to grow cannabis is relatively easy, and you only need to follow five steps. You can go for a ready-made setup or set one up yourself. 

Step 1: Prepare the lid

Drill a hole

First, you need to fix the lid on your reservoir. For this, cut the top with a drilling machine or any other tool to create a hole large enough for a net pot to get through. 

Step 2: Fill the reservoir with water

Fill water

Next, fill the reservoir with water. You can use both tap or distilled water, but avoid using dirty or contaminated water at all costs — the water will be stagnant throughout the process, and you don’t want it to turn into a pest haven!

Step 3: Prepare the nutrient solution

Add nutrients

Add the nutrients one by one to the reservoir and mix the water thoroughly. Or, you can mix the nutrients in another container separately and add it all at once to the reservoir. 

Step 4: Check the pH levels

Check pH

Your Kratky culture is almost ready! Now, it’s time to check the pH balance using a pH pen or meter. The reservoir’s pH balance should be between 5.8 and 6.2, an ideal range for the cannabis plant.

Adjust pH

If it’s not in the suitable range, increase or decrease the pH before proceeding.

Step 5: Plant cannabis

Plant cannabis

Fill the net pot with growing media and insert your seedling into the pot. Next, place the net pot in the drilled lid of the reservoir. While doing so, ensure some of the roots are exposed to air while its lower parts are in the nutrient solution.

How does the Kratky method work to grow cannabis?

As mentioned already, the Kratky method works on a few basic principles of effortlessly supplying water and oxygen to the plants. This simplistic method allows you to continue your business rather than worrying about the plants. 

As long as you monitor the pH levels and check the plants for pests, deficiencies, and diseases frequently, you can grow some stunning plants with this method. 

Are there any drawbacks?

Everything has drawbacks, and the Kratky method is no different. You may encounter some disadvantages, including:

  • The Kratky hydroponic system has many variables, like pH levels and temperatures, affecting the plant’s growth.
  • The Kratky method is only suitable for small cannabis cultures. A big culture would require a lot of manual labor in cleaning and preparing the systems, which is not worth it.
  • The method is also prone to pests because of the lack of air stones and stagnant nutrient solutions, attracting pests like gnats and mosquitoes. So be prepared to deal with pests beforehand. 


The Kratky method to grow cannabis is the perfect way for beginners to get started with growing cannabis. So, if you do things right — use the right kind of tools, water, medium, and nutrients while maintaining stable temperatures and pH, you will grow a healthy cannabis plant right at home.

Compared to other methods, the Kratky is by far the easiest. And, even if you take a DIY approach, it shouldn’t cost you more than $30-$40 to gather a container, lid, and some water. 


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