The Kratky Method: A Simple and Efficient Beginner’s Hydroponic System

Hydroponics is a revolutionary method of growing plants that eliminates the need for soil and allows for precise control over nutrient delivery. While there are several types of hydroponic systems available, one method stands out for its simplicity and efficiency: the Kratky method. Developed by B.A. Kratky from the University of Hawaii, this passive hydroponic technique has gained popularity among both commercial growers and home gardeners.

Understanding the Kratky Method

The Kratky method is a form of passive hydroponics that does not require the use of pumps, electricity, or wicks. It is a non-circulating system where plants are suspended above a reservoir of nutrient-rich water. This method is often referred to as “the simplest hydroponic system” due to its minimalistic design and ease of use.

In the Kratky method, plants are placed in net cups filled with an inert growing medium such as rock wool, expanded clay aggregate, sphagnum moss, or coconut coir. These net cups are then suspended above a reservoir filled with water and essential nutrients. The roots of the plants partially submerge into the water, allowing them to absorb both water and oxygen.

As the plants grow and consume water, the water level in the reservoir gradually decreases. This creates an air gap between the water surface and the base of the plants, providing the roots with access to oxygen. The plants continue to thrive in this passive system until they are ready for harvest.

Advantages and Benefits of the Kratky Method

The Kratky method offers several advantages and benefits for both commercial growers and home gardeners:

  1. Simplicity and Cost-effectiveness: The Kratky method requires minimal equipment and is easy to set up and maintain. It eliminates the need for pumps, electricity, and complicated water circulation systems, making it a cost-effective option for hydroponic gardening.
  2. Water Efficiency: Unlike traditional soil-based gardening, the Kratky method uses less water. The water in the reservoir is only consumed by the plants as they grow, eliminating the need for water replenishment or frequent irrigation.
  3. Nutrient Control: With the Kratky method, growers have precise control over the nutrient solution. They can customize the nutrient mix and concentration based on the specific needs of the plants, resulting in faster and healthier growth.
  4. Low Maintenance: Once set up, the Kratky system is relatively low maintenance. Growers do not need to constantly monitor and adjust water levels or nutrient solutions. This makes it an ideal choice for busy individuals or those new to hydroponics.
  5. Versatility: The Kratky method can be used to grow a wide range of plants, including leafy greens, herbs, and even larger plants like tomatoes and peppers. It is a versatile system that can adapt to the needs of different plant species.

Setting Up a Kratky System: Step-by-Step Guide

Now that you understand the basics of the Kratky method, let’s dive into the step-by-step process of setting up your own Kratky system:

Step 1: Choose the Right Container

The first step is to choose a suitable container for your Kratky system. The size of the container will depend on the size of the plants you plan to grow. You can start with something as small as a mason jar for small plants, or opt for a larger container like a 5-gallon bucket for larger plants. Ensure that the container is opaque to prevent sunlight from reaching the roots and promoting algae growth.

Step 2: Prepare the Lid

Next, you’ll need to prepare a lid for your container. The lid serves multiple purposes—it prevents evaporation of the nutrient solution, supports the plants above the water, and protects them from pests and diseases. You can use a plastic lid or even a piece of styrofoam as long as it fits securely on top of the container.

Step 3: Choose the Right Net Pots

Net pots are essential in the Kratky system as they hold the growing medium and allow the plants’ roots to reach the nutrient solution. Choose net pots with suitable sizes for your plants. The Hydrofarm Net Cup is a popular choice for many growers. Fill the net pots with an inert growing medium like hydroton, rockwool, or coconut coir.

Step 4: Mix the Nutrient Solution

The nutrient solution is the key to providing plants with essential nutrients for their growth. You can prepare the nutrient solution by using a hydroponic fertilizer like General Hydroponics Nutrient 3 part package. Follow the recommended dosage and mix the nutrients with water in the container. Stir the solution thoroughly to ensure even distribution of nutrients.

Step 5: Check and Adjust the pH Level

The pH level of the nutrient solution is crucial for optimal plant growth. Use a pH meter to measure the pH level of your solution. The ideal pH range for most plants in hydroponics is between 5.5 and 6.5. If the pH level is too high or too low, you can use a pH control kit to adjust it accordingly. Regularly monitor the pH level to maintain a balanced environment for your plants.

Step 6: Plant Placement

Now it’s time to place the net pots with the plants onto the lid of the container. Ensure that the roots are partially submerged in the nutrient solution while the top portion of the roots is exposed to the air. This allows the plants to access both water and oxygen. Adjust the position of the net pots to ensure stability and proper nutrient uptake.

Step 7: Monitor and Maintain

Once your Kratky system is set up, the key is to monitor and maintain the water level in the container. As the plants grow, they will consume the water, and the water level will gradually decrease. It’s important to ensure that the roots always have access to the nutrient solution. If the water level becomes too low, you can add more nutrient solution to replenish it.

Step 8: Harvesting

The Kratky method allows plants to grow until they are ready for harvest. Leafy greens and herbs are particularly well-suited for this method as they have a fast-growing rate. When the water in the system is almost depleted, it’s a good indication that your plants are ready to be harvested. Simply remove the net pots from the lid, harvest the plants, and enjoy your fresh produce!

Best Plants for the Kratky Method

The Kratky method is ideal for growing a variety of plants, especially leafy greens and herbs. Here are some popular choices for the Kratky system:

  1. Lettuce: Lettuce is one of the most common plants grown using the Kratky method. Its fast-growing nature and shallow root system make it well-suited for this passive hydroponic system.
  2. Spinach: Spinach thrives in the Kratky system and can be harvested within a few weeks. Its nutrient-rich leaves make it a nutritious addition to any meal.
  3. Basil: This aromatic herb grows exceptionally well in the Kratky system. Its vibrant leaves and intense flavor make it a popular choice for culinary enthusiasts.
  4. Cilantro: Cilantro is another herb that flourishes in the Kratky system. Its distinct flavor adds a refreshing touch to various dishes.
  5. Kale: Known for its nutritional value, kale is a nutrient powerhouse that can be easily grown using the Kratky method. Its sturdy leaves and cold tolerance make it a great choice for year-round cultivation.

While leafy greens and herbs are the most common choices for the Kratky method, you can also experiment with other plants like tomatoes, peppers, and cucumbers. Keep in mind that larger plants will require a larger container and more frequent monitoring to ensure proper water and nutrient levels.

Potential Challenges and Considerations

While the Kratky method offers many benefits, there are a few challenges and considerations to keep in mind:

  1. Plant Size and Container Selection: The Kratky method is best suited for small to medium-sized plants. If you plan to grow larger plants, you will need a larger container and may require more frequent monitoring to ensure adequate water and nutrient levels.
  2. Pest and Disease Control: As with any gardening method, pests and diseases can pose a challenge. Ensure that your Kratky system is adequately protected from pests and diseases by using a secure lid and maintaining proper hygiene practices.
  3. Water and Nutrient Management: While the Kratky method is low maintenance, it’s important to monitor the water and nutrient levels regularly. Ensure that the roots always have access to the nutrient solution, and adjust the levels as needed to support optimal plant growth.
  4. Environmental Factors: Temperature fluctuations and extreme weather conditions can affect the performance of your Kratky system. Choose a suitable location for your system, preferably indoors or in a controlled environment, to minimize the impact of external factors.
  5. pH and Nutrient Adjustments: Regularly check and adjust the pH level of your nutrient solution to maintain optimal plant health. Ensure that the nutrient solution is well-balanced and provides all the essential nutrients required for plant growth.

By being aware of these challenges and considerations, you can effectively overcome them and enjoy successful hydroponic gardening with the Kratky method.


The Kratky method is a simple and efficient hydroponic system that offers numerous benefits for growers of all levels of experience. Whether you’re a commercial farmer or a hobbyist gardener, this passive hydroponic technique allows you to grow healthy and abundant plants without the need for complex equipment or constant monitoring.

With the step-by-step guide provided, you can easily set up your own Kratky system and start enjoying the benefits of hydroponics. From leafy greens to herbs, the Kratky method provides a versatile platform for cultivating a wide range of plants.

Remember to choose the right container, prepare the lid, select suitable net pots and growing media, mix the nutrient solution, monitor the pH level, and maintain proper water levels. With a little effort and attention, you’ll be rewarded with a thriving hydroponic garden that produces fresh and nutritious plants.

So why wait? Dive into the world of hydroponics with the Kratky method and experience the joy of growing plants in a simple and efficient way. Happy gardening!


Located in Portland, Oregon, Tim started gardening in his 20's and after a couple of decades felt like he had some things to share.

Recent Posts