How to do Kratky: the easiest hydroponic system
Kratky is by far the easiest method of hydroponic gardening. Many systems require water pumps and air pumps. Kratky however, doesn’t need either. If you keep your system in a sunny window, in your yard, or on a balcony, you don’t even need a grow light. You can even make succesful Kratky systems with stuff around your house.
What is Kratky?
Kratky is named after its inventor, Bernard Kratky. The Kratky system requires nutrient solution, seeds, and a bucket with a top panel that contains planting sites that are open to the inside of the bucket.
The bucket is filled with the nutrient solution and the seeds are placed in the planting sites so that they make contact with the solution. No other change is made for the lifetime of the plant.
How to Make a Kratky System
Make a Single Plant Kratky
My blog post on how to grow Arugula in a jar is a modified Kratky system. The principles can be extrapolated to multi plant gardens as well. Take a look in order to get hands on experience with Kratky!
Make a Multi Plant Kratky
The Arugula in a jar project will help you to get acquainted with the core concepts. With a bathroom garbage pail, a piece of packing foam, and a box cutter, you can quickly scale up to three plants! Check out this system that I made in order to experiment with growing tomatoes hydroponically…
1 inch rockwool cubes are pushed into the 1x1 inch holes cut in the foam slab. The foam slab makes contact with the nutrient solution so that the plants can consume water and nutrients.
The only things I purchased in order to make this system were the nutrients, the rockwool, and the tomato seeds. I live in an area where my neighbors leave a lot of trash on the street, so that’s how I got the foam and the trash can. This is an upcycled hydroponic system!
If you’re ready for an even bigger Kratky, think about purchasing a set of 10 gallon storage containers and a rotary tool to cut holes in the top of them in order to create the planting sites.
Above are some 20 gallon sterilite containers that I used to grow Basil, Cilantro, and Arugula. 3 inch net cups are placed in holes that I cut out if the tops with my rotary tool. The 3 week old plants, which were germinated in 1 inch rockwool cubes, are placed inside the net cups, and stabilized with Hydroton clay pebbles. The nutrient solution was made with General Hydroponics MaxiGrow.
Read through the following tips for Kratkying successfully in order to figure out how to dose out nutrients and manage water level properly.
Tips for Kratkying Successfully
The concept of Kratky is very simple. The plants get nutrients and water from the nutrient solution so that they can grow. The high level definition however, misses some key details that will make your grow successfull.
Nutrition requirements change over the lifetime of a plant
The idea of one time setup is not totally realistic. 2 week old seedlings require much less nutrients than month old plants. Seeds also require no nutrients during their first week of life. Adding nutrients at this time may pull water out of your plant through the power of osmosis, causing it to wilt and die.
For the best results, follow the advice in the all purpose nutrition schedule section of my blog post about EC and plant nutrition.
Plants' roots need Oxygen
Plants need Oxygen as well as nutrients and water in order to grow. Don’t completely submerge your plant’s roots in the nutrient solution. Instead, only cover 1/4 to 1/3 of the bottom of the plants roots in solution. The result will look something like this Kratky’d Ball jar system.
Take a look at my blog post on growing Arugula in a jar for an easy get-started-with-Kratky DIY project.
The materials used are listed in the post and can also be used in a larger Kratky setup.
Keep light out of the bucket
Keep as much light out of the bucket as possible in order to keep algae from growing. Use a dark colored bucket. Lighter colored PVC totes that are white or yellow, will let more light through than a green, brown, or black one.
It’s still possible to grow successfully with a light colored bucket though. I have used a few light colored ones, myself. You may have to change the water a little more often in order to keep the algae down.
This post explains more about the affect of algae growth on pH and nutrient availability.
Using lots of water is time consuming and expensive
I have personally made Kratky systems that require tons of water. Manually changing out 100 gallons of water every ten days can take a lot of time and effort depending on how you dose out your nutrients, adjust your pH, and where you keep your Kratky system.
For larger systems, simple nutrient blends and a garden hose are a must.
A nutrient blend like General Hydroponics MaxiGrow is very affordable and you only have to measure once per bucket, which is so much easier to use than something that requires mixing multiple parts together (trust me).
Now you’re ready to Kratky!
Get started with the Arugula in a jar hydroponics project and then scale your setup into 3 or more plants using sterlite containers or any other container that you have laying around.
What I love most about Kratky is that you can grow your own food without having any land or construction skills! It’s truly the best way to get into hydroponics.
