Basil growing in the Kratky method

The Ultimate Guide to Grow Basil Using The Kratky Method

Basil is adored worldwide, yet only some have the space or time to nurture it. Hydroponics could help, but few are competent in soil-less culture. This is where the Kratky method comes in handy. This post will walk you through growing basil using the Kratky method.

The Kratky method can grow basil and many other herbs and vegetables anywhere. For example, you can cultivate them on your rooftop or balcony, near your window, or entirely indoors with the help of grow lights. This method can also be implemented for large-scale industrial cultivation.

The beauty of basil is that it’s a very resilient plant. As long as there’s full sun, moisture around the roots, and a warm climate, basil could thrive. Likewise, Kratky doesn’t need electricity, and it’s super simple to set up.

The Kratky hydroponics technique.

The Kratky hydroponic technique is a game-changer for those looking to grow plants hydroponically with minimal fuss. Developed by Bernard Kratky, a researcher at the University of Hawaii, this method stands out for its simplicity and low-maintenance nature. Unlike other hydroponic systems that require electricity, pumps, or water circulation systems, the Kratky method is entirely passive. Here’s a closer look at how it works and why it’s an excellent option for home and small-scale growers.

How the Kratky Method Works

The Kratky method involves suspending plants above a reservoir filled with nutrient-rich water. The key here is that only the tips of the roots touch the water surface. As the plants grow, they consume the water in the reservoir. This consumption creates a gap of moist air between the water surface and the plant base. The roots in this gap become “oxygen roots,” which absorb oxygen from the air. This natural process negates additional aeration typically required in other hydroponic systems.

You can read Dr. Kratky’s original papers to learn more about his work:

Three noncirculating hydroponic methods for growing lettuce

A suspended pot, noncirculating hydroponic method

Key Advantages of the Kratky Method

  1. Simplicity: The Kratky method is straightforward and requires minimal intervention. Once the system is established, it’s essentially a “set-and-forget” method, making it perfect for busy individuals or those new to hydroponics.
  2. No Electricity Needed: Since the method does not require pumps or water circulation systems, it eliminates the need for electricity. This reduces costs and allows for the setting up hydroponic systems in areas without reliable power sources.
  3. Low Maintenance: The Kratky method is very low, with no moving parts or complex systems to manage. Monitor the water level and add more nutrient solution if necessary, although the initial supply often lasts the entire growth cycle for specific plants.
  4. Affordability: The Kratky method is an affordable entry point into hydroponics because it does not require expensive equipment like pumps or timers. The primary costs are the reservoir, nutrient solution, and growing medium.

Ideal Plants for the Kratky Method

The Kratky method is particularly well-suited for growing leafy greens and herbs. Plants like lettuce, spinach, basil, and cilantro thrive in this setup as they do not require large amounts of water. The initial water supply and nutrients allow these plants to complete their entire growth cycle, making the system low-maintenance.

Limitations to Consider

While the Kratky method has many benefits, it has some limitations. It is not ideal for plants that consume much water, such as tomatoes or cucumbers. These plants might deplete the water reservoir too quickly, requiring frequent refills and defeating the method’s low-maintenance appeal. Heavy or oversized plants might also need additional support structures, as the basic Kratky setup might not provide sufficient stability. Of course, you can work around and grow almost any plant using the Kratky method. But in its simplest form, it’s perfect to grow leafy greens and herbs.

How to set a Kratky hydroponic system to grow basil

Herbs and leafy greens are relatively easy to grow in hydroponics. Because we focus on their edible foliage, we don’t have to worry about pollution in the case of fruiting vegetables or rotting root vegetables. Also, herbs and leafy greens have pretty straightforward nutrient needs.

Also, most basil varieties are annuals and about two feet in height. Thus, you don’t need as big a container for basil as you’d need for vegetables like pumpkins or tomatoes. You can even grow them as a companion for other plants.

Related: Basil As A Companion Plant: 5 Plants You Can Grow With Basil For Best Results.

Here’s all you need to set up a Kratky system to grow basil. Remember to include basil seeds.

ItemBuy Now
Food Grade BucketUnited Solutions 5 Gallon Bucket
Net CupAC Infinity Net Cups 3-Inch
Hole SawKATA 6PCS Hole Saw Kit
Peat PalletsJiffy Peat Pellets
Hydroponic NutrientsMASTERBLEND 4-18-38 Complete Combo Kit Fertilizer
pH AdjusterGeneral Hydroponics pH Kit
pH & EC MeterVIVOSUN Digital pH and TDS Meter Kits

Now that we have everything we need to grow basil using the Kratky method, here are the steps to follow.

Step I: Prepare the container.

Drill a hole in the middle of the lid. The hole size should match your net cup size. Net cups, 2 or 3 inches in diameter, would be perfect for basil. Thus, pick a matching hole saw.

Step II: Fill the container with water

Fill the container with pH-neutral water. RO water would be ideal, but you can collect rainwater or tap/well water. Check the PH and EC of the water. You can use this water if the pH is close to 7 and EC is less than 0.3. You can adjust the pH with a pH adjuster if the pH is different. If the EC is too high, you must change the water source.

Related: What Are the Best RO System and Role of RO Water in Hydroponics

Related: How to Treat and Use rainwater in hydroponics?

Step III: Prepare parts A and B solutions.

In a two-part hydroponic nutrient solution, part B is always calcium nitrate. Your NPK + micronutrient fertilizer is your part A. Often, you need to mix Epsom salt to complete part A. Note that you have to prepare them in separate containers to avoid precipitation of some compounds.

Take one pound of Masterblend 4-18-38 (equal fertilizer) and half a pound of Epsom salt. Dissolve them in one gallon of water one after the other. This is your part A.

For part B, dissolve one pound of Calcium nitrate in another gallon of water.

Step IV: Mix the nutrients in the container.

You can add the nutrient solutions we’ve prepared to your Kratky container. You have to do this little by little. Every time you add part A, you must add the same amount of part B to the container. After every step, you need to check the solution’s EC. You can stop adding nutrients when you reach roughly 2-2.4 EC.

Related: Nutrient Requirements For Hydroponic Basil: Mixing, Fixing and Diagnosing

Step V: Finish the setup

Close the bucket with the lid on. We’ve put a hole in it for the net cup. Now, place the net cup in the hole. Also, place a jiffy peat pallet inside the net cup. The pallet should be in contact with the nutrient solution in the container. After a minute or two, the peat pallet will expand to its full size after being soaked in the nutrient solution.

Step VI: Sow the seed

As we’ve completed the setup, place a basil seed on the peat pallet. You’ll see a little hole for the seeds. You don’t need to cover the seeds with more coco peat, but it’s optional.

Step VII: Place it in a sunny area

Basil needs abundant light. Moving your container to a sunny area would be best, and basil should receive at least six hours of sunlight. Alternatively, you can install a grow light to supplement the sunlight or grow fully under artificial light. In both cases, you must have the lights on for about 10-12 hours daily.

Related: How Much Light Does Basil Need?

How to care for hydroponic basil

Basil plant under full sun light

Basil grown in hydroponic systems requires minimal care, primarily if you use the Kratky method. But there is a thing or two you need to know.

Kratky’s method uses the suspended roots to breathe oxygen. Yet, compared to other systems like DWC, Kratky’s chances for root rot are high.

If the water level is too high and there are not enough suspended roots, root rot may appear. Although as the plant grow, the water level may go down, sometimes the plant’s growth may be stunted for various reasons. In other cases, rainwater may enter the container and cause the water level to rise if you’re growing outdoors. All these will contribute to root rotting.

Thankfully, basil could come back from root rot real fast. You can cut off the affected roots and treat the rest with diluted hydrogen peroxide to reduce the impacts.

Root Rot in basil grown in the Kratky method.

Related: Fixing Root Rot in Hydroponic Basil

While too much water can cause root rot, there’s too little nutrient problem too. Sometimes water level may go down faster than we think. Excess transpiration or even a leak in the bucket may cause this. In such cases, basil will show symptoms of nutrient deficiency. Usually, the plant turns pale yellow and eventurally die.

Basil needs full sun and good airflow. Without enough airflow basil may develop infections like fusarium wilt and downy mildew. And, although basil repells most pests, it’s not immune to all the creatures. Basil is susceptible for leafminer attacks. You could treat them with organic pesticides like neem oil. Or simply installing a insect net would prevent most of the issues.

Related: Hydroponic Basil Pests and Diseases

Related: 7 Tips to Avoid downy mildew in basil

Lastly, not an issue, but a good practice, is to pinch the flowers of basil. Basil when they bloom turns more mature. It’s leaves become more tender and start to taste bitter. Some varieties even looses their aroma too.

Related: How often can we harvest basil?


Basil is a popular herb that you can grow easily. Compared to many other plants, basil is rescillient and it has very simple nutrient requirements. As long as you’ve got enough nutrient and ample sunlight, your basil will grow wild.

Because of it’s natural fast growth and relative ease, you don’t need complex hydroponic systems to grow basil. The most basic, Kratky method would be more than sufficient to grow basil.

Although, basil grows well in Kratky, you need to be aware of a few things like root rots, pests and diseases, etc. Growing in the right way, basil grown in Kratky method woudl yield bountyful harvest almost every other week.

Related: How To Prune Basil For A Flavorful, Bushy Plant Forever

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