Homegrown lettuce in the dead of winter or the heat of late summer? It’s possible with hydroponics. And you don’t need a fancy setup with electric pumps and a water circulation system. The Kratky method lets you do it with a grow light and an empty coffee bin. 

Developed by horticulturist Bernard A. Kratky of the University of Hawaii at Manoa, the Kratky method is ridiculously simple. Plant roots need access to oxygen. When grown outdoors, a plant’s roots find this oxygen in air pockets within the ground. In a commercial hydroponic system, pumps circulate air to the plants’ roots. In the Kratky method, an air pocket is formed as the roots take up water, lowering the water level. This air pocket provides all the oxygen a plant needs at the root level.   

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