What is the Kratky Method of Hydroponics?

The Kratky method of hydroponics is a passive hydroponic technique that is a simple and easy way to grow plants without the need for a lot of equipment. This method is great for growing plants in a small space, and it is also a great way to grow plants for food or medicine. The only downside to this method is that the plants can etiolate if they do not receive enough light.

What Are The benefits of the Kratky Method of Hydroponics?

The main benefit of the Kratky method is that it is a very simple and easy way to grow plants. This method does not require a lot of equipment, which makes it great for growing plants in a small space. Additionally, this method is great for growing plants for food or medicine. The only downside to this method is that the plants can etiolate if they do not receive enough light.

As the plant grows and depletes the water level, a gap of moist air will form and expand between the water surface and the base of the plant.

Who Invented the Kratky Method?

The Kratky method of hydroponics was invented by Bernard Kratky, a professor at the University of Hawaii.

Learn more about Dr. Kratky and the Kratky Method

Kratky hydroponic indoor garden with basil, tomatoes, lettuce, cilantro, green onion and more. Growing in mason jars using the Kratky method of hydroponics.

Imagine growing hydroponic lettuce, tomatoes, basil, cilantro, green onions and so much more right in your own home using a simple method called Kratky Hydroponics and the Kratky Method of growing.

Now imagine doing it all through the winter too. That is what indoor Kratky hydroponics can do for you.

Kratky Lettuce growing in mason jars in an indoor Kratky hydroponic garden using grow lights.
CZ Net Cups for Kratky Containers

Net Cups

These are our absolute favorite 2-inch Net Cups by CZ.

Mason Jar Container Covers

Container Covers

Quickly and easily block out the light to minimize algae growth.

Kratky Hydroponic Growing Materials - Rock Wool Grow Cubes

Rock Wool Cubes

These are the best grow blocks we have used in our growing.

12PCS Kratky Lids Wide Mouth Hydroponic Cover Lids Kratky Mason Jar Lids Kratky Lid Insert Kratky Jar Cover Hydroponic Lids Kratky Hydroponics Supplies with Hole for Mason Jars Aerogardens Pods

Kratky Lids

We love these lids for our containers, they totally block out light.

Grow 250+ lbs hydroponically indoors using the Kratky Method of Hydroponics in a very small space!

Kratky squash grown in mason jars

What I Grew with Two Kratky Hydroponic Gardening Shelfs & 2 LED Grow Lights

I use only two shelves on a standard 5 x 2 foot shelf that sits in my office. With only two grow lights, I am able to grow over 250 pounds of lettuce, tomatoes & herbs for my family. Learn all about the Kratky method of hydroponic growing here!

The way we use Kratky is a non-circulating technique. Without the need for soil, the Kratky method allows me to grow plants, fruits and vegetables in simple containers. You can aerate the plants easily with an added pump, but we find the Kratky method needs very little aeration, as the roots are suspended in air above the water.

LEFT: Kratky grown yellow squash growing and flowering! It started blooming indoors, so I transplanted it outside.


Learn About the Kratky Method of Hydroponics

Kratky Method of Hydroponics - Design a Kratky Hydroponic System

Kratky Design

See how I setup a simple Kratky hydroponic method indoors on two 5×2 foot shelfs – easy peasy!

Watering hydroponically with passive hydroponic techniques for growing plants suspended above a reservoir of nutrient-rich water.

Kratky Maintenance

The Kratky method is easy to setup and maintain. No weeds + infrequent watering.

Kratky Method of Hydroponics - Design a Kratky Hydroponic System

Cleanup for Kratky

Cleanup is easy. No fuss or mess, just pop your tools and such in the dishwasher and you are done.

The Kratky Method of Growing Hydroponically - How to grow using the Kratky Method

Kratky Small Plants

The key to growing in a small space is size. Selecting varieties that stay small is important.

Using the Kratky Method of Hydroponics means no mowing, weeding and no soil!

No Mowing or Weeds

All the yard work is eliminated with Kratky Hydroponic systems. No weeding, no mowing.

Grow fruits and veggies with the Kratky Method - Kratky Lettuce, Kratky Herbs, Kratky Tomatoes and all sort of plants!

Kratky Fruits & Veggies

Grow fruits and vegetables in containers. From strawberries to tomatoes and lettuce.

Kratky Hydroponics - Growing Plants Hydroponically With Kratky

Kratky Flowers

Start your flowers indoors or simply grow indoor varieties with ease. Either way are gorgeous.

The Kratky Method of Growing Hydroponically - How to grow using the Kratky Method

Transplant Outdoors

And when the time comes, you can harden off and move your hydroponics outdoors.

My Indoor Kratky Hydroponic Garden

I love to grow things indoors. Taking care of seedlings & watching my food grow right before my eyes. The fresh taste of all these gorgeous varieties can’t be beat anywhere.

Kratky Methed of Hydroponics growing in Mason Jars - Kratky Hydropincs Using Mason Jars

My little seedlings growing in my Kratky Hydroponic system. I grow most of my hydroponics in mason jars in less than 20 square feet in my office.

Kratky Strawberries - how to grow strawberries using the Kratky method of hydroponics

Seedlings under the led grow lights in the Kratky Hydroponic indoor garden in my office.

Key Facts About Kratky Hydroponics

Passive System: Operates without the need for electricity, pumps, or aerators.

Simplicity in Design: Ideal for beginners due to its straightforward setup and low maintenance.

No Soil Required: Utilizes a water-based solution rich in nutrients, eliminating the need for soil.

No Soil Required: Utilizes a water-based solution rich in nutrients, eliminating the need for soil.

Efficient Water Use: More water-efficient compared to traditional soil gardening.

Suitable for Leafy Greens and Herbs: Particularly effective for growing plants like lettuce, spinach, and various herbs.

Kratky hydroponic vegetables
Best nutrients for Kratky method
kratky method of hydroponics

Low Cost: Requires minimal investment in equipment and resources.

kratky method of hydroponics

Scalability Limitations: Best suited for small-scale gardening rather than large-scale commercial operations.

kratky method of hydroponics

Nutrient Solution Management: Requires careful preparation and monitoring of the nutrient solution.

kratky method of hydroponics

Eco-Friendly Option: Reduces the need for chemical fertilizers and pesticides compared to some traditional farming methods.

kratky method of hydroponics

Indoor and Outdoor Flexibility: Can be set up both indoors with grow lights or outdoors in natural light.

kratky method of hydroponics

Customizable Setups: Allows for a range of container sizes and types, adaptable to different spaces and needs.

kratky method of hydroponics

Organic Growing Potential: Compatible with organic nutrients for a more sustainable approach.

kratky method of hydroponics

Direct Nutrient Absorption: Plants have direct access to nutrients in the water, promoting efficient growth.

kratky method of hydroponics

Minimal Pest and Weed Problems: Reduced risk of pests and weeds compared to soil-based gardening.

kratky method of hydroponics

Visual Monitoring of Growth: Enables easy observation of root development and water level.

kratky method of hydroponics

Space Efficiency: Ideal for urban settings or areas with limited gardening space.

kratky method of hydroponics

Reduced Labor Intensity: Less labor-intensive than traditional gardening methods.

Hydroponic gardening Kratky

Principles of the Kratky Method

kratky method of hydroponics

Passive Hydroponics

Plants are suspended with their roots partially submerged in nutrient-rich water.

Nutrient Solutions

kratky method of hydroponics


Balanced mix of macro (N-P-K, Magnesium, Calcium) and micronutrients (Iron, Manganese, Boron, etc.).

kratky method of hydroponics


Dissolving water-soluble fertilizers in water to the correct concentration.

kratky method of hydroponics

pH Levels

Ideal pH is around 5.5 to 6.5 for optimal nutrient uptake.

kratky method of hydroponics


EC (Electrical Conductivity) or TDS (Total Dissolved Solids) meters are used to ensure appropriate nutrient strength.

DIY Kratky nutrients
Hydroponic fertilizers

Plant Selection and Management

kratky method of hydroponics

Ideal Plants

Best for leafy greens like lettuce, spinach, and herbs.

kratky method of hydroponics

Seed Starting

Seeds can be started in rockwool cubes or other inert growing mediums.

kratky method of hydroponics


Once roots develop, plants are transferred to the Kratky setup.

kratky method of hydroponics


Plants are harvested once they reach maturity, typically not replanted in the same solution.

System Setup

kratky method of hydroponics


Use non-transparent containers to prevent algae growth.

kratky method of hydroponics


Adequate space between plants is crucial for growth and access to nutrients.

kratky method of hydroponics


Natural light or grow lights if indoors.

kratky method of hydroponics

Temperature and Environment

Stable temperatures and protection from extreme weather are necessary.

Kratky method guide
Hydroponic Gardening - Everything You Need to Know

Build Your Dream Hydroponic Indoor Kratky Garden

Would you like to create your own indoor hydroponic system using the Kratky method? Lisa will show you how she setup an entire garden on 2 5×2 shelfs – that’s 20 square feet! Grow lettuce, tomatoes, basil, cilantro, green onions, strawberries, peppers and more using this easy to learn system.

Recommended Glass Containers for The Kratky Method of Hydroponics

Mason Jar Glass Container for Kratky Hydroponic Gardening Containers

Wide Mouth Quart Size

We love the wide mouth quart size for smaller plants.

Small Kratky Containers for Clones and Seedlings

Containers for Herbs & Clones

We love to grow our clones in a pretty display! Works for herbs.

Gallon Kratky Container Mason Jaw Wide Mouth

Complete Basil Kit with

This kit has everything you need to grow basil in a kitchen window.


kratky method of hydroponics


Easy to set up and maintain, ideal for beginners.

kratky method of hydroponics

Energy Efficiency

No electrical components required.

kratky method of hydroponics


Low initial and ongoing costs.


kratky method of hydroponics

Limited Scale

More suitable for small-scale operations.

kratky method of hydroponics

Nutrient Management

Imbalance or depletion of nutrients can affect plant health.

kratky method of hydroponics


Regular checking of water level and nutrient concentration is required.

Maintenance and Troubleshooting

Water Level

Keep an eye on the water level and refill if it drops too fast.

Nutrient Replenishment

Top up nutrients if the solution gets depleted.

Pest and Disease Control

Regular inspection for pests and diseases; use organic pest control methods if necessary.

Kratky method setup
Hydroponic nutrient solutions

Innovations and Variations

Hybrid Systems

Some gardeners experiment by combining Kratky with other hydroponic systems.

Automated Monitoring

Incorporating sensors and IoT for monitoring water levels and nutrients.

Environmental Impact and Sustainability

Water Usage

More efficient than traditional soil gardening.

Chemical Use

Reduction in pesticides and herbicides.

Organic Options

Organic nutrient solutions are available for a more sustainable approach.

Nutrient-rich solutions for Kratky

“Wow, I love Lisa’s easy to follow Kratky method instructions!”

Lisa keeps it simple and simply shows us what we need to do with the Kratky method, without things we just don’t need to know. We used her techniques and grew tons of stuff. Indoors!

 “Imagine growing lettuce in a small space using Kratky, who would have thought?”

I still pinch myself when I see all of my little plants growing in such a small space. While Lisa did not invent the Kratky method or techniques, the way she explains it is perfect.

“A salad right in the other room, just pick it! I love this Kratky stuff!”

I was drawn to growing fresh lettuce and tomatoes in the hard winter in Minnesota. Now with prices sky high, I sure am glad I am growing my own varieties right using Kratky hydroponics.

Recommended Plastic Containers for Kratky Hydroponics

5 Gallon Plastic Containers used for Kratky Container Gardening

5 Gallon Plastic Buckets

The perfect size for growing Kratky Container Tomatoes and they are FOOD GRADE.

4 Bucket Plastic Containers for Kratky Hydroponic Container Gardening

4 Bucket Hydroponic System

No work hydroponic gardening system with 4 containers. Includes aerator and net cups.

2 Gallon Plastic Containers for Kratky Hydroponic Gardening Smaller Plants

Two Gallon Plastic Containers

These are great for your plants that do not take up. as much space or water.

What Can You Grow With Kratky Hydroponics?

Kratky Method Of Hydroponic Lettuce Grown Hydroponically Using Kratky

Kratky Lettuce

A Bowl of Lettuce Grown Hydroponically Using the Kratky Method

Kratky Hydroponic Lettuce

One of the best uses for indoor growing without soil using the Kratky method is to grow lettuce. Lettuc by far is the easiest vegetable to start with and grows well in the Kratky mason jar method. I gorw all types and varieties of lettuce.

Growing Lettuce The Kratky Way is Better

Unlike other plants grown hydroponically, lettuce grows fast and can be grown in a small container with little to no attention for it’s entire lifespan, which is often cut to less than 20 days using the Kratky method of hydroponics.

Types of Lettuce that Grow with Kratky

Honestly, Kratky hydroponic growing works well for all types of lettuce. Since you will be growing indoors or outdoors without soil, the temperature is more of a factor than anything. Some varieties prefer colder weather than what may be present under grow lights.

Some of the most popular varieties are:

  • Red Leaf Lettuce
  • Green Leaf Lettuce
  • Bibb Lettuce
  • Romaine Lettuce
  • Iceberg Lettuce
  • Coral Lettuce
  • Escarole
  • Looseleaf Lettuce

We suggest you just try what you like and see how it grows. Many leafy greens grow well in a Kratky hydroponic garden.

Other Favorite Hydroponic Plants

Hydroponic tomato plants in Kratky containers using Kratky growing methods.

Kratky Hydroponic Tomatoes

Everyone loves a ripe, warm tomato just picked from the garden. But when winter comes, we are forced to buy them from the local grocery store and they simply don’t taste the same. We can grow tomatoes all dang year indoors. There are some great dwarf or micro varieties that are great for indoors or limited space gardens.

Basil grown with the Kratky Method of Hydroponics in mason jars without soil. Kratky method hydroponics gorws prolific plants.

Kratky Hydroponic Basil

Growing basil is fun and rewarding. If you are a beginner hydroponic gardener, you must grow basil. Hydroponic systems provide plenty of water, which is great for herbs, especially basil. Combine your basil with your Kratky grown tomatoes for a special treat. Lettuce simply thrives using Kratky mason jars.


Dwarf cucumbers in the hydroponic garden - started in mason jars with grow lights.

Kratky Hydroponic Cucumbers

While cucumbers may not seem like a good choice for growing hydropoincally indoors, there are many dwarf varieties that can help if you are in. alimited space. Outdoors, the sky is the limit. Cucumbers not only grow well with Kratky hydroponics, they thrive in it.


What is the Kratky method in hydroponics?

The Kratky method is a passive hydroponic system where plants grow in a nutrient-rich solution without the need for electricity, pumps, or aerators, allowing the plants to absorb water, oxygen, and nutrients as needed.

Can the Kratky method be used for any type of plant?

While the Kratky method is versatile, it’s most effective for leafy greens and herbs. It may not be suitable for larger fruiting plants or those requiring more support.

What are the best nutrients for the Kratky hydroponic system?

The best nutrients for the Kratky method are complete hydroponic fertilizers that include essential macro and micronutrients like nitrogen, phosphorus, potassium, calcium, magnesium, and trace elements.

How often should the nutrient solution be changed in the Kratky method?

In the Kratky method, the nutrient solution typically does not need changing; the system is designed for the solution to be used up as the plants grow.

Can the Kratky method be scaled for commercial production?

Yes, the Kratky method can be scaled for commercial production, but it requires careful planning in system design and nutrient management to ensure consistent plant growth and health.

How do you prevent algae growth in the Kratky method?

Prevent algae growth in the Kratky method by blocking light from reaching the nutrient solution, often by using opaque containers or covering exposed surfaces.

What is the ideal water level for a Kratky hydroponic system?

The ideal water level in a Kratky system allows plant roots to partially immerse in the nutrient solution while leaving some roots in the air for oxygen absorption.

How do you manage pests and diseases in the Kratky method?

Manage pests and diseases in the Kratky method through regular monitoring, maintaining cleanliness, using organic pest control methods, and selecting disease-resistant plant varieties.

How is aeration achieved in the Kratky method?

Aeration in the Kratky method is achieved passively as the water level drops, allowing more root surface to be exposed to air, thus eliminating the need for artificial aeration.

Can the Kratky method be automated?

The Kratky method is inherently a non-circulating, passive system, but aspects like nutrient monitoring and replenishment can be automated for larger-scale operations.

What is the lifespan of a Kratky hydroponic system?

The lifespan of a Kratky system depends on its construction materials and maintenance, but with proper care, it can last for several growing seasons.

Can the Kratky method be used indoors?

Yes, the Kratky method can be used indoors, provided that there is sufficient light, either natural or through grow lights, and stable environmental conditions.

How do you handle water evaporation in the Kratky method?

Handle water evaporation in the Kratky method by periodically checking and replenishing the water level to maintain the appropriate nutrient solution volume.

Can multiple plants be grown together in the Kratky system?

Multiple plants can be grown together in the Kratky system, but ensure they have similar nutrient requirements and enough space for root growth.

What types of containers are suitable for the Kratky method?

Suitable containers for the Kratky method are non-transparent, to prevent algae growth, and have enough depth and volume to accommodate the nutrient solution and plant roots.

How do you determine the right nutrient mix for the Kratky method?

Determine the right nutrient mix for the Kratky method by considering the specific nutritional needs of the plants being grown and following the guidelines provided by the nutrient manufacturer.

Is the Kratky method suitable for organic gardening?

The Kratky method is suitable for organic gardening as long as organic, soluble nutrients are used and organic growing principles are followed.

How does temperature affect the Kratky hydroponic system?

Temperature affects the Kratky system by influencing nutrient uptake, plant growth, and potential for pathogens; optimal temperature range varies by plant species.

Can the Kratky method be combined with other hydroponic systems?

While the Kratky method is distinct in its passive approach, it can be combined with other systems for experiments in hybrid hydroponic techniques, though this requires careful planning and execution.