This unique clock promises to run on completely free energy – no batteries or outlets required. The Soil Clock from Dutch designer Marieke Staps uses the natural metabolism of biological life to power its display, requiring only the periodic addition of water.
The Soil Clock has two small electrodes trailing from it which plug right into the soil. The electrodes contain copper and zinc, metals which work with the soil’s natural electrolytes to create enough clean electricity to keep the clock running virtually indefinitely.
Although the clock can run with just soil and water, the designer recommends putting plants into the soil. This is both to make the entire setup more beautiful and to remind you to keep the soil moist. If the plants die, you’ll suddenly be out of time.