We define visible light that’s naturally produced by the sun coming in your home through your window/glass door or the strong ambient light produced by your fixtures. Because most buildings in the city are clustered, we do not use the term “South-facing windows”, most likely your windows are blocked by buildings or not facing in the ideal direction, unless you reside in high-rise building. If you experience all four seasons during the year, or in a space with low light, you will need to consider moving plants from one space to the other or obtaining additional light to provide the necessary light frequency to help your plants produce healthy new growth.