The Joensuu root laboratory is platform for studying the effects of environmental conditions on above- and belowground plant processes, especially in the context of climate change. The platform consists of four walk-in growth rooms and six growing containers in each growth room. The soil temperature and moisture in the growing containers can be controlled independently from those of the air. Light conditions can be also controlled, as well. The annual cycle can be accelerated and typically, 2.5 growing seasons can be conducted within one calendar year. Soil conditions are recorded at three depths and a water table can be maintained. Plant measurements include a large variety of morphological, anatomical, physiological, and phenological parameters. A special feature is a minirhizotron camera for studying root growth. The platform has been used mostly for studying plants in environmental stress conditions, like responses of boreal forest trees to soil frost or water-logged soil.