Off The Grid Kratky Method - No Soil or Power Required

Hydroponics has often been labeled as too much work and too costly to grow due to high lighting costs and constant attention to nutrient levels. Professor Bernard Kratky discovered a way to eliminate most of the hassle and perfected a very easy way to grow plants. We have researched this in great detail and have tested many different ways of using this system to grow food and other plants. The Guru started out experimenting by growing Basil in 2 liter plastic bottle containers. We found that the method not only worked, but the Basil plants rooted faster and out grew the Basil plants from the same batch that were bought on the same day that we planted in soil.

The results were amazing, every Basil plant using this Kratky method grew faster, thicker and better than anything grown in deep water culture or the other hydroponic methods. This method of growing plants is not new. Most of the attention and expense in hydroponics goes into other systems that use high power lights, water pumps and air pumps. Those systems for growing plants require much time and money for success.

This Kratky system is a cheap and easy way to grow food or flowers that anyone can do even if they do not have any prior experience growing plants. This is important because the soil quality in every country is getting more and more polluted. You can still buy nice soil at stores but who wants to spend $7.00 for 1 cubic foot of potting soil. Many people still compost but that also takes time and resources. The Kratky method works great with almost no money or labor needed. We will cover how to make a Kratky set up and what you will need to do this cheaply from reused or re-purposed materials.


Building Your System – You will need:

The plastic or glass container to hold the water and nutrients. If you are growing large plants a clean 5 gallon plastic bucket with lid works great. Do not use if it previously held harsh chemicals or oil that could damage the plants – or you.

Clay stones or hydroponics pebbles

Net pots – use one to trace the size onto the top of water container. A 3 inch hole saw or a sharp utility knife to cut a hole for the net pot.

Trace around the net pot and cut INSIDE that line to make the hole -if you do not have a hole saw.

Cut out the hole for your net pot to snugly fit into.

Wash your clay stones or pebbles to remove all dirt.

Mix your hydroponic nutrients as per the manufactures instructions. Do not add more nutrient than it says, over doing it will kill your plants. If you are using non hydroponic fertilizers – start off using about 1/2 of their recommended mixing amount. You can also use lake water or fish tank water. These will have more odor and smell to them so if you are growing inside this is something to think about.

Fill your container until the bottom of the net pot or cup has about a half inch of water in it. See the pictures below.

Rinse your baby plant roots off in room temperature water to remove any soil or growing medium and place one into the center of the net pot or cup. If you can get a root or two to hang down below the pot that will be great.

Add your clean rocks or clay stones and place the net pot into the hole in the top of the container.

If you are growing small plants like Basil or lettuce you can just use foam rubber around the plant stem to hold it in place. Just make a smaller hole about 1 – 1 1/2 inches in the container lid, or just use the 2-4 liter bottle spout, and then wrap a strip of soft foam rubber around the plant stem and carefully push it into the hole. Make sure that the roots of the plant hang down so that about 1/2 are in the nutrient solution and 1/2 are in the air space at the top of your container. No net pot or grow medium needed !


Place your plant in sunlight or in a window. You may also place it under a CFL bulb or grow light if you have electricity to spare.

Because your plant will be growing for several weeks or months in this container you have to prevent green algae from growing on the roots in the nutrient solution.  You can do this by using a dark container — or spray painting it black — before you put the plant in. If you decide to paint your container you should first put a VERTICAL strip of narrow tape on it, which you can peel off after painting so that you can check the water level easily.  You can also use aluminum foil or a black paper cylinder wrapped around the container – then all you have to do is lift that up to see the nutrient water level.

That is all there is to it.

For the first week or so the plants will not look happy. They will look droopy as they adjust to the new environment. After a short time you will see large amounts of new growth.

The medium which holds the plant is called the growing medium. It may include a wide range of substances like rockwool, coconut fiber, perlite, vermiculite, sand, gravel, wood chips etc. This growing medium is an inert substance which is not responsible for supplying any nourishment to the plant, its only purpose is to hold the plant in place.


Understanding Nutrients:

When using the Kratky method in hydroponics your nutrients act as plant food much like soil does. Your nutrients will supply the fertilizer and food for your plants.

For a dry mix nutrient powder I use HYDRO-GARDENS CHEM-GRO POPULAR HOBBY FORMULA 10-8-22. Mix 1 teaspoon 10-8-22 and 1/2 teaspoon Epsom salt MgSO4 per 1 Gallon of Water.

If you don’t want to mix, buy Fox Farm liquid nutrients because it is a pre made consistent mix of the water and nutrients. I have used the same bottle for 3 years. It will cost about $20.00 but you only use a very small amount in the mix.

About every one or two months you should redo the system by adding fresh water and new nutrients. Follow the directions printed on your nutrient package. Over doing the mixture strength will cause nutrient lockout or even kill your plants by burning the roots.

If you are using a commercial pre-made nutrient mix remember that most of them are salt based. This is important because you will need to add water about once a week to keep your water levels right. Don’t panic… I know I said you do not need to worry about watering.

If the water level gets low it will not kill your plants. It will not even hurt your plants unless you don’t add water for a month or so and the plants totally dry out. Outside in 90 degree temperatures you will see more water loss. So as you add more water the salt level will rise. I add pure water most of the time.


Understanding Roots:

Plant roots need air. I know that these roots that are are normally buried underground and need air seems crazy. This is why Kratky hydroponics works. You do not want to cover all the roots with water and nutrients. You only want the normal water lever to cover about 25% of the bottom of your net pot. As the roots grow and the plant feeds it will lower the water level to just below the bottom of the net pot. Some roots will still dangle down into the water. This is why you do not have to worry about watering as much. As long as some of the roots are touching the water the plant will get plenty of nutrients and the root tops will have air.

Roots are delicate. Always be careful when handling the roots. Avoid touching them if at all possible. Everything on your hands will contaminate your plants. Also the roots do not like rapid temperature changes. You would not want to top off your container with freezing cold water. If you stress the roots you will stress the plants weakest link. Healthy roots will always equal bigger yields and happier plants.

When growing in a hydroponic medium you want to look at your roots for the overall health. You are looking for clean white thick roots. The roots should be much thicker than normal roots would be. This is why hydroponic plants grow so much faster and better. Many people have reported that the growth is more than double a soil based plant. I would agree with this based on what I have seen. In a Kratky setup there is no air stone so your roots will not be a white as a deep water culture system. This is ok since the size and overall health is still great. We want to get nutrients into the plant but we do not want to over do it.



In the beginning your plant is starting to develop roots that will hang down into the water. At first this level is critical because the plant needs some water to make it through the transition. Once the roots start to grow down, the water level will drop down and as long as some of the roots still touch the water it will keep the other roots moist and allow the plant to keep growing.

When you transplant your new plant into your Kratky system you must make sure that the water comes up to the net pot or cup and covers about 25% of the bottom of the net pot or cup. This way one or two little roots are touching the water. Because your container is sealed it will minimize water loss. Most of the water will be used by your plant.

When your water and nutrient level gets down to about 25% of the bottle or container add water to bring the level up to 50% – but not higher, the air space is important. Check your plants about once a week. As the plant gets bigger after maybe a month or so you can add water every other week if needed. Large plants like tomatoes or peppers will need to be topped off more as they get bigger. A large tomato plant can drink as much as a gallon of water in a day. The absolute worst thing that can happen to your Kratky system is that it can dry out. This will stop all growth and will kill your plant. You will not have to worry daily about watering most smaller plants. Tomatoes and other plants when fruiting need much more water because the Kratky system causes rapid growth in the stem and fruits. Imagine 10 tomatoes on a plant that is sucking up water all day in 90 degree weather. Keep them wet….

Cheap Lighting : The Bulb

CFL or compact fluorescent bulbs will not put off much heat and they will cause growth in most plants. You will need to get the lights very close to the plants. Your hardware or home store will have some larger 150 watt equivalent bulbs that work great for most any plant. I have grown plants indoors all winter long under these bulbs. At a purchase price of about $20.00 per bulb they are worth it. I also use the aluminum dome shaped reflectors that you can buy at a home store. These direct heat and light towards your plant. The bulbs do not use much electricity so you can leave them on several hours at night to also light your room without breaking the battery bank.



This is my favorite type of lighting. Totally off the grid and 100% free. You can adjust the brightness with sun shades and nothing will promote better plant growth. The sun is best used during the growing season. I grow plants for free food so I like to grow everything I can during the summer grow season and store what I need for later. We also are into canning food for later. You can move outdoor plants under a shade tree if they do not like a ton of light. You can put some inside in a window if they need less heat but still want the light.

I can not say enough about the power of the sun. If you enjoy being off the grid (unplugged from the power company) then you understand the sun provides electricity and warmth.  Solar panels will produce power that can be stored in batteries and used later for lighting and charging gadgets. 12 volts DC will run all sorts of things but many people still use 120 volts AC appliances because that is what is sold in the stores and they are easily available.

I will not get off on a rant. Just know that the sun provides everything we really need, you just need to know how to use it. When growing with the sun you need to keep a sharp eye on your water levels so that your plants stay happy. However when using the Kratky hydroponics method you do not have to worry about watering very often.



If you are using seeds you will need to plant them in a sterile growth medium and let them root well – before moving them into the Kratky system. Loose seeds will fall into the nutrient solution and will never grow. I like to plant them and wait a month or so for them to root before they go into my Kratky system.


To start more Kratky systems, clone cuttings or tomato plant sucker trimmings work great. I normally clone in a cool area – a kitchen window is great. I have a normal florescent light above the sink that is used at night for about 6 hours. I also have sun light coming in during the day. It is normally about 74 or so in my house. This is ideal for cloning plants. Once the clones have developed a good root structure I put them into a new Kratky system. Normally this takes about 2-3 weeks . 

There is nothing to stop you now — get Kratky-ing ……..