Kratky Method Guide: Simple Set Up Hydroponic System

Hobbyists and gardeners are familiar with several hydroponic systems, but among the category, the Kratky method is the easiest and simplest.

Hydroponic can be the solution if you have trust issues with vegetables from the markets and soil problems in your private garden.

The usual hydroponic system needs air stones, tubes, water pumps, air pumps, as well as a continuous electricity supply to aerate the nutrient solution.

Thus, one mishap, like a single power cut can create a disaster for your expected crop.

This is when the Kratky method saves you. With this system, you could get rid of the need to use those supplies mentioned above. Is this interesting or what?

This page will disclose further information about the Kratky method, including how it works, how to build one, and what the pros and cons this hydroponic system have in store.

However, before we go there, you should know what it is first.

Q: What is the Kratky Method of Hydroponics?

A: The Kratky method is an innovation in the no-soil gardening field developed by Bernard A. Kratky, a University of Hawaii’s horticulturist.

With all respect to him, because of his determination, we now know the simplest way to build a hydroponic system.

No hassle whatsoever, the Kratky method only requires the desired seed or young plant, net pot, nutrient solution with proper pH value, and well-covered container or water reservoir.

How Does It Work?

If it is as simple as stated, how does even the Kratky method work to encourage the plants’ growth?

Well, except for soil, this setup provides the basic requirements for vegetations, including hydroponic light, water, and air.

The deal is the same as any other soil-less gardening system since there are no soil-borne nutrients for hydroponic plants.

We provide them using an external source of soluble fertilizer mixed in water. It then fills the container and supports the growing medium.

Most of the roots soak in the solution, while the rest remain in the air. Complete this setup by placing it in the shaded area with enough sunlight exposure.

The water amount will decrease gradually as the plant grows until it completely dissipates. Only after then, the plant is ready to reach the harvest phase.

Setting One up

Since it is an easy setup, everyone can make one by him/herself by gathering the supplies and following the building steps.

The Requirements

Preparing the supplies comes before anything, so gather the following things first.

– A water reservoir or a container made of easy-to-drill/cut material, with a lid
– Growing fertilizer (hydroton or rock wool)
– Net pot
– Nutrient solution
– PH kit
– Seeds or a young plant you want
– Water

Step One

How to grow plants hydroponically using the Kratky method? Firstly, choose the seeds or young plant you want.

You should take note that your selection affects the container size. A 2-liter reservoir might be enough to accommodate lettuce, spinach, and other small plants.

On the other hand, a 5–8 gallon bucket will be necessary for pepper, tomato, and other bigger plants.

Step Two

Make holes on the container lid using a drill, big enough so that each could hold one net pot. Pay attention also to the spacing hydroponic plant.

Why should you use the reservoir with a cover? Well, it helps to bear the root part where the water could not reach.

Besides, the lid creates circulation space for damp air the underneath roots. Less direct contact between the solution and the plant aids to prevent the possible diseases that might appear at the collar zone.

Step Three

After drilling the lid, add water into the container until it is almost full. Then, make sure to leave enough space between the water level and the lid to provide the plant with air.

Next, use distilled water to get the best result, but you could utilize contamination-free tap water also.

Step Four

Dilute the nutrient with proper ratio into the water-filled reservoir. Make sure you go thoroughly according to the instruction to have the crop you expect.

Step Five

Check the solution’s pH value. It should be in the range of 5.5 to 6.5. Use a pH kit to adjust the suggested level.

Step Six

Place your plants or seeds and the growing fertilizer in the net pots, and fit them onto the holes on the container lid.

If you decide to start it from seeds, soak the rock wool completely wet first before placing the unit on the drilled cover.

The seeds will then reach the germination phase inside it, and roots will grow downwards into the water. Meanwhile, if you choose to go with a young plant, most of the roots must soak in the solution.

Then, leave some other hang in the space between the water level and the container lid to let this Kratky method works.

What do you think of the steps above? It is more than doable, right? You could repeat the process for more plants. However, not all vegetations can strive through it.

Q: What can you grow with the Kratky method?
A: It encourages leafy green crops, such as spinaches, lettuces, and herbs, better than the other plants. The reason lies in the plant’s rapid growth and the growing space.

The larger the vegetation, the bigger the container you will use. It leads to the more effort you should take to supervise the vegetation’s growth.

Tips and Trick

Growing hydroponic plants through the Kratky method is super easy, yet you should bear the following things in mind.

1. Starting from seeds requires a completely wet growing fertilizer. Remember to check its condition now and then, do not let it gets dry. Dried rock wool can lead to unhealthy seedlings.
2. If you decide to start with a young plant, eliminate any dirt around the roots first before planting it in the system.
3. The system should be on an even-level surface to keep an even water mixture level.
4. Cover the system well to prevent any outside water from getting in. A tiny amount of it might be tolerable, but more than that could disrupt the solution’s pH level.
5. Maintain the system by keeping the temperature and pH level on regular check.

Possible Problems

Growing plants indoors with the Kratky method is easy. However simple and beneficial this technique is, it still has some flaws since no product made by humans is perfect.

1. Since the Kratky method works with stagnant water, the possibility of how it attracts pests like mosquitoes is high. Ensure that the system has good coverage while letting the air to circulate.
2. Until the harvest time comes, you will not replace the solution used in the system. If you start the project with not-so-good-quality water, the salt concentration might be dangerous.

Pros and Cons

Like a two-sided coin, everything in the world has upsides and downsides of its own. The same applies to the Kratky method. Below is a list of the pros and cons of this hydroponic system.


1. The Kratky method does not cost you highly. The supplies involved are those of affordable price and easy to find.
2. It does not depend on the electricity to work, thus any power cut whatsoever will not affect the growth of the plants.
3. The Kratky method is a perfect technique for beginners since no strict supervision is necessary.


1. As stated previously, the Kratky method encourages the growth of small green leafy plants better than it does to any other types. In other words, this system is only ideal for such vegetations.
2. The number of vegetation that it can accommodate with each planting is only as much as the family portion.
A larger garden or commercial farm cannot get any benefit from the Kratky method since they intend to produce a large number of crops.


Q: What is the best hydroponic method?
A: In terms of the easiness for novices, the Kratky method is the best in the category. The basic supplies are not difficult and not pricey to get.

Q: Can you refill Kratky?
A: The nutrient solution will be running out when it is time to harvest. You can refill the mix without emptying the reservoir.

Q: How much water do you use for the Kratky method?
A: The suggested ratio for a head of lettuce is one gallon of nutrient solution. That much water can last for four to six weeks.
Once the water is completely running out, starting over the planting with new seed is only natural.

Q: What are the six different types of hydroponic systems?
A: Gardeners and hobbyists are familiar with Ebb and Flow, Aeroponic, Drip system, Wick, NFT, and Water Culture hydroponic systems.

The six mentioned here are the basic methods. From here, people combine some to get hundreds more.


You need to neither be an expert nor spend so many to consume fresh and healthy crops since the Kratky method exists. With this system, enjoy a low-cost yet high-quality meal right from your garden! Congrats!