A California company is using robots to grow plants in greenhouses that it says use 90 percent less water than traditional farms. The company, Iron Ox, operates several greenhouses and has plans to expand. It recently announced a new $50 million investment. The financing was led by Breakthrough Energy Ventures, a company established by Microsoft founder Bill Gates. At a 930-square meter center in Gilroy, California, Iron Ox uses a self-driving robot named Grover to transport containers of plants. The large greenhouse uses hydroponics, a system designed to grow plants in materials other than soil, such as water. The company says each container, known as a module, carries 30 liters of water and about 70 seedlings as it moves. Another machine uses robotic arms to lift the top of the plants out of the water. This permits the roots to be inspected. Sensors also examine the water, measuring levels of nitrogen and acidity. Iron Ox claims the system uses 90 percent less water than traditional farms, as well as 90 percent less electricity than indoor farms using LED lights. LED stands for light emitting diode, which produces light up to 90 percent more efficiently than regular lights. Sarah Osentoski is the company’s senior vice president of engineering. She told Reuters news agency she believes robots like these can help prepare for a more sustainable future. “I think it’s a really exciting way we can move forward in agriculture right now,” Osentoski said. “I really believe that we need to grow in a way that could feed the future of the world without hurting the Earth,” she added. “So, a big part of our mission is to grow more with less.” The company notes that in its greenhouses, any water not used can be pumped back into the system to be reused later.