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How to Set Up a Kratky Hydroponic System

The Kratky Hydroponic System is one of the many variations of the hydroponics system. It is also easy to set up and would require only a little bit of maintenance, making it a top option for farmers that want to grow simple crops faster and better. 

In this guide, we are going to take you through what the Kratky method actually is and how you can set up the system.

how to set up a kratky hydroponic system

What is the Kratky Hydroponic System?

The Kratky method is a farming system developed by horticulturist Bernard A. Kratky of the University of Hawaii at Manoa. It is considered the simplest and easiest hydroponics method.

This system eliminates the need for pumps, bubblers, wicks, or timers that are needed in other hydroponics systems. It also requires no electricity making it a great option for DIY farmers looking for a cost-effective hydroponics growing system. 

How Does The Kratky Hydroponic System Work?

The Kratky hydroponic system works just like the deep water culture hydroponics system with the difference being the lack of an air pump, air stone, and tubing in the Kratky method.

In the Kratky method, a reservoir or container is filled with a mixture of water and nutrients for the plants. A lid is placed on top of the reservoir with a gap left between the surface of the water and the lid. This allows air to flow into the lid and aerate the plants.

Seedlings of the plant to be grown are placed into a hydroponic growing medium inside a net cup. The net cup is then placed in a hole on the lid so that the bottom of the cup touches the liquid containing nutrients inside.

With that the system setup is complete and you can watch the plants grow. 

The roots of the plant absorb the nutrient-rich water which feeds the seedling. The seedling will naturally shoot its roots down into the solution as it grows. When it comes to an oxygen supply, the fact that the net cup is only touching the water, rather than being submerged in it, allows the top of the root system to get all the oxygen it needs.

Unlike a system like deep water culture, the entire net cup is submerged in water leaving the root system without enough oxygen. The addition of an air stone and air pump is needed to provide the needed oxygen. The Kratky method solves this by leaving that gap of air above the water, giving the plants’ roots all of the oxygen they need.

As the plant takes in the water and nutrients, the water level will drop and the roots will grow down with it ensuring they’re never truly submerged. 

By correctly measuring the amount of water needed from the start, you won’t have to refill the system. This makes it easy to maintain and the only truly passive system of hydroponics.

What Plants Grow Best With the Kratky Method?

In general, you will be able to grow small plants with short growth cycles in the Kratky method. You can start with leafy gresn and popular vegetables like kale, spinach, lettuce, bok choy, and collard greens. You can also grow herbs like basil, chives, dill, cilantro, endive, and sage.

How to Set Up A Kratky Hydroponics System

When setting up the Kratky Hydroponics System, you will only need a handful of materials to get started.

Equipment You Will Need For Your Kratky Hydroponic System:

  • A container or reservoir – This is the growing container that will hold the water and nutrient solution. 
  • A lid – The lid will consist of several holes in which your plant will sit. The lid also blocks pests away from the roots of the plant and slows down the evaporation of the liquid.
  • Net cups – These plastic cups feature several holes at the bottom. They will hold the seedlings and allow its roots to go through the holes to ensure they reach the water. 
  • Growing medium – Your seedlings require a substrate from which to grow. In hydroponics, the options range from rockwool, coconut fiber perlite, to hydroton. This will support the plant and hold air and moisture.
  • Hydroponic fertilizer – In hydroponics, the plants get nutrients from the water rather than pulling it from the soil. To ensure they get the right nutrients, you will have to combine liquid or solid nutrient mixes in the water used to feed your plants.
  • Water – You will need clean water in which you will mix the nutrients. This will be delivered to the plants via the roots.
  • Seeds – You can start with seeds or germinate them before putting them in the Kratky system 
  • pH Control – Plants need a slightly acidic medium to grow. YOu can use inexpensive home pH testing kits to ensure that the water has the right pH for your plants and solutions to tweak the pH to get it back on track.

How To Build a Kratky Hydroponic System

Once you have all the material in place, you can follow this step-by-step guide on how to build a simple Kratky hydroponic system.

  • Step 1: Get the container that will hold the water and nutrient solution. If you’re only going to go a single plant, a mason jar would be perfect. However, if you would like to grow many plants at the same time, you would need to go for a large container. 
  • Step 2: Drill a hole in the lid of your container (as many holes for the number of plants you need to grow). The holes should be large enough to fit the net cup but not exactly the size of the net cup so it doesn’t fall over. 
  • Step 3: Soak a hunk of rock wool in water and place it in the net cup. Throw in the seeds you want to grow into the hole in the rock wool.
  • Step 4: Place the net cup into the hole you drilled in your container. Fill the container with clean water until the water level reaches the bottom of the net cup.
  • Step 5: Wait for the seeds to begin to sprout before adding them to the water.