A plant factory is a large building that grows plants inside. Instead of growing plants in the sun and soil outside like a traditional farm, plants in a plant factory are grown inside a climate-controlled room with special lights, machines, and other equipment. Plant factories don't need sunlight, so they can be used all year round and in any type of weather. This makes them great for growing a lot of plants at once and growing plants that may not normally be able to grow in certain climates.