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Kratky Potatoes: Growing Potatoes Without Soil

Kratky Potatoes is run by Portside Marketing. We grow potatoes with the Kratky method, a passive hydroponic technique that needs no pumps, no air stones and no electricity, and we share what we learn here.

This site is for home growers who want to grow potatoes without a garden bed. You might have a patio, a garage or a basement grow shelf, or you might just want to know whether a potato can grow in a tub of nutrient solution. It can, with a few changes that leafy greens don't need.

What the Kratky method is

The Kratky method was developed by Dr. Bernard Kratky, a researcher at the University of Hawaii. A plant sits in a net pot in the lid of a container filled with nutrient solution. As the plant drinks, the level falls and leaves an air gap. The upper roots take in oxygen from that gap while the lower roots keep drinking. You fill the container once, or top it up now and then, and nothing needs to run.

For more on the method itself, and how potatoes fit into it, see the potato page on our main site, Kratky Method of Hydroponics.

Hydroponic potato plants growing in totes
Hydroponic potato roots filling a net pot

Why potatoes need a different setup

Lettuce only needs leaves and roots. Potatoes also need somewhere to form tubers. Tubers grow on underground stems called stolons, and they form only in the dark. Light turns them green, and green potato skin contains solanine, which you shouldn't eat. So a Kratky potato container needs:

  • Depth: room below the lid for stolons and tubers, above the falling solution.
  • Darkness: opaque walls and a lid that blocks light.
  • A loose medium such as perlite or coco coir in the root zone, so tubers have something to form in.
  • Plenty of solution, because a full-size potato plant drinks far more than a head of lettuce.

What to expect

Expect a smaller harvest than a good soil bed gives. Kratky potatoes are a project for learning and for fresh new potatoes, not a replacement for a field. Early varieties that finish in a shorter season are the easiest place to start.

Start here