# Kratky method

> The Kratky method is a passive hydroponic system with no pumps: plants sit above a container of solution, and a growing air gap forms as the level drops.

- Canonical: https://genetixbay.com/knowledge/glossary/kratky.html
- Also written: kratky, Kratky hydroponics, passive hydroponics, non-circulating hydroponics, set and forget hydro
- Glossary category: Systems and media · Evidence: Supported
- Status: Draft: awaiting expert review · Updated: 2026-10-31
- Licence: CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0/), attribute "GenetixBay cannabis glossary"

The Kratky method, developed by B. A. Kratky at the University of Hawaii, is a non-circulating hydroponic technique. A plant in a [net pot](https://genetixbay.com/knowledge/glossary/net-pot.md) sits in a lid over a tank filled with nutrient solution. As the plant drinks, the level falls, leaving an [air space](https://genetixbay.com/knowledge/glossary/air-filled-porosity.md); the upper roots adapt to breathe in that humid air while lower roots keep drinking. No pump, [air stone](https://genetixbay.com/knowledge/glossary/air-stone.md) or electricity is needed.

## In practice

Kratky works very well for lettuce and herbs. For cannabis, which drinks large volumes and is grown for months, it needs a big container (tens of litres per plant), a starting [EC](https://genetixbay.com/knowledge/glossary/ec.md) and [pH](https://genetixbay.com/knowledge/glossary/ph.md) set carefully, and top-ups with weak solution rather than refilling to the top, which would drown the air-adapted roots. Warm solution and stagnation make [root rot](https://genetixbay.com/knowledge/glossary/root-rot.md) more likely. Some growers use it for seedlings or small autos, or as a learning tool.

## Don't confuse with

- **DWC**: actively aerated with an air pump.
- **Wick system**: passive, but feeds a medium through a wick.

## Related terms

[DWC](https://genetixbay.com/knowledge/glossary/dwc.md), [Hydroponics](https://genetixbay.com/knowledge/glossary/hydroponics.md), [Net pot](https://genetixbay.com/knowledge/glossary/net-pot.md), [Dissolved oxygen](https://genetixbay.com/knowledge/glossary/dissolved-oxygen.md)

## Read more

- [Kratky (passive, non-circulating hydroponics)](https://genetixbay.com/knowledge/systems/kratky.md)

## Sources

1. Kratky BA, 2004. A suspended pot, non-circulating hydroponic method. Acta Horticulturae 648:83–89. https://www.ctahr.hawaii.edu/hawaii/downloads/A_Suspended_Pot_Non-circulating_Hydroponic_Method.pdf