Cultivation of plants in nutrient-enriched water, with or without the mechanical support of an inert medium such as sand or gravel. Fertilizer solution is pumped through the system periodically. As the plants grow, concentration of the solution and frequency of pumping are increased. A wide variety of vegetables and florist crops can be grown satisfactorily in gravel. Automatic watering and fertilizing saves on labor, but installation costs are high and fertilizer solution must be tested frequently. Yields are about the same as for soil-grown crops.