Grow plants using the Kratky hydroponics method [Easy Guide]

Grow plants using the Kratky hydroponics method [Easy Guide]

Growing plants in water and nutrients is easier than you think. However, does it work at all? in this article, we will look at setting up your own Kratky hydroponic system and see whether or not the Kratky method of hydroponics works for growing plants without soil just using water and nutrients.

Introduction to hydroponics systems

Introduction to hydroponics systems

Before we dive into the article let’s talk a little bit about the hydroponic systems.

There are two types of hydroponic systems: the active or the aerated type also called deep water culture and the passive type like this Kratky hydroponic system.

The Kratky method of hydroponics which was invented by Bernard Kratky at the University of Hawaii is one of the simplest hydroponic systems.

Here are some differences between the two systems.

Here are some differences between the two systems.

As you can see the active system requires air stones connected to a pump and multiple parts and accessories. The Kratky system however only requires limited parts for setup.

In the Kratky method of hydroponics, the water and nutrients last for the entire life of the plant and do not need to be replaced.

Things needed to set up the Kratky method of hydroponics

Things needed to set up the Kratky method of hydroponics

So here are the items you will need to set up your own Kratky hydroponic system. You will need a container. The best size container I have found is the storage tote which you can get at your local Costco or home depot. This 27-gallon tote can store enough water and nutrients for most plants.

Next, you will need a three-inch hole saw. The best one I found was at our local home depot.

You will also need some three-inch net cups. these are available for cheap on amazon.

You will also need pumice or some kind of clay aggregate to hold the plant in the net cups.

For nutrients, you will need the MasterBlend nutrients that work best for the Kratky method. You will also need calcium nitrate which supplies calcium and nitrogen.

And finally, you will need Epsom salt or magnesium sulfate.

Setup the system (Kratky method of hydroponics)

Setup the system (Kratky method of hydroponics)

All right so the first step is to mark the areas where you will be drilling holes for the net cups. It’s easier to measure and mark areas where the net cups will go, that way the plants will be equally spaced.

The trick is to go in the forward direction first to drill the center hole and then go back to drill the larger hole.

Once done you can remove the small plastic pieces at the edges. A good-quality hole saw will give you a clean cut.

Now there are a lot of plastic pieces that will be left in the tote, discard them and wash the tote thoroughly.

We are now ready for the next step which is adding water and nutrients to our Kratky hydroponic system.

Adding water and nutrients to our Kratky method of hydroponics

Adding water to our Kratky method of hydroponics

Fill up the tote with 25 gallons of water. It’s important to make sure that the water level touches the net pots about halfway through, not below it, and not drowning it completely.

The plant grown in a Kratky hydroponic system has both water roots and air roots. So the water level is very important.

Next, we are going to add nutrients. We will need to measure it by weight.

Adding nutrients to our Kratky method of hydroponics

The first nutrient is the master blend mix. It has a lot of the macronutrients like nitrogen, phosphorus, and potassium along with trace nutrients. Measure it and keep it separate.

Measure and keep Epsom salt ready. Epsom salt is magnesium and sulfur. The sulfur also alters the ph slightly making the solution acidic which is important for plants to take up nutrients from the nutrient solution that we are creating.

Measure calcium nitrate and keep it aside. This adds sources of calcium and nitrogen to the nutrient solution.

And here’s a warning do not mix these salts together. They must be mixed one by one in the nutrient solution. I cringe when I see some users mixing all the salts together, it does not work well as these salts react with each other.

There is a reason why we are using different salts, we mix them in one at a time and the instructions are very clear on this one.

So start with the master blend mix that you had measured and mix it well into the water.

Mix in the Epsom salt that you had measured and mix it well into the water solution. Next, mix in the calcium nitrate and give it a good swirl to dissolve it completely.



All right now our water solution is ready and we now close the lid and start planting our plants in the net pots.

You do not have to use hydroponically germinated seedlings. You can use seedlings grown in the soil if you wish to, as they are easily available at your local nurseries.

The seedlings we are using are bok choy seedlings grown in soil. We will use pumice to support our plant. You can use clay pebbles or rock wool or anything else you want to use.

We are planting three bok choy plants and three cauliflower plants here.

Set all the plants in the net pots and we are done. This is all we need to do. The plants will grow well and use the nutrient solution for the rest of their life cycle.

Harvesting hydroponic bok choy

Harvesting hydroponic bok choy

So it’s been a few weeks since we planted these and now we can begin harvesting the bok choy. The leaves are amazing, no pests or diseases as we are growing in a nutrient-rich solution only, not soil.

The bok choy also tasted amazing and there was absolutely no maintenance needed after planting. A few days after harvest the bok choy plant has grown back again and is producing more leaves.



So what’s our conclusion for the Kratky hydroponic method? Well, it does work very well for leafy greens like bok choy, lettuce, and herbs. I wouldn’t use it to grow larger veggies. For the larger veggies, I think the deep water culture works better.

The other thing to note is that the growing method takes up quite a lot of space. Technically you can stack them in growing racks but the container is just too heavy, so you ideally should not stack them.

But this is also the same problem with an active system or the deep water culture system so not really a con of the Kratky system.

But overall I really enjoyed growing my bok choy in this Kratky hydroponic system and I got a really good harvest from this system.

take a look at the roots

Now just take a look at the roots. When you lift up the lid you can see all the beautiful roots and the roots at the top that are a little spiky are the air roots and this is because roots need oxygen to grow.

But they also need water roots which you can find at the bottom. These are the roots that will take up nutrients from the water solution.

So the Kratky hydroponic system is very interesting. It allows for both air routes and water routes and lets the plants grow to their full potential. So overall I really enjoyed setting up the Kratky hydroponic system and growing bok choy and getting a good harvest.

The Kratky hydroponic system is highly recommended if you’re beginning hydroponics. It’s a great hydroponic system for the first time hydroponic grower, it’s easy to set up, it requires very less parts, it has no moving parts at all and once you add the solution the plants grow for the rest of their life cycle.

So all in all very easy to use and something that I highly recommend you try out.

There we have it folks that’s our article on the Kratky hydroponic system for growing your plants. If you liked this article please share it with your friends and family and if you have any questions comments or thoughts put them in the comments box below. Happy gardening!

I am Fenil Kalal. Professionally I have done Engineering in Information and Technology. Gardening is my passion/love/favorite hobby and I have 5+ years of experience in Gardening.

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