Plant growth is a very complex process. Photosynthesis is one of the major key players in helping plants grow. The leaves on the plant are especially important as they are the sites of photosynthesis. During photosynthesis, plants use sunlight, carbon dioxide, and water to produce glucose and oxygen. Glucose is a type of sugar that serves as an energy source for plant growth and development.
Along with the photosynthetic process, the plant itself has photoreceptors that help them respond to light and adjust their growth direction to maximize exposure.
For indoor plants, they use the light from grow lights to carry out photosynthesis. That is why grow lights are a must for houseplants. Also, like with natural sunlight, some plants benefit from a long photoperiod of light coming from grow lights. A photoperiod is the length of light and darkness in a day. As mentioned in my other post “How do plants grow,” light is one of the external factors that influence plant growth. Feel free to read my other post for more information about plant growth.