Table 1. Role of water in plant growth vs reduced water supply to plants

Environmental plant growth factors:
There are various environmental factors which has a significant role to play in enhancing the growth of plants. The environmental plant growth factors include:

1. Light
2. Temperature
3. Relative humidity
4. Carbon dioxide and Oxygen
5. Soil

1.  Light: Light quality refers to the color or wavelength reaching the plant's surface.  Adequate light is one of the most important factors that influence the growth of plants and it is the quality, quantity and duration of light exposure which matters. Various natural and artificial light sources can be used to provide light to the plants. Red and blue light have the greatest impact on plant growth whereas green light is least effective.  Blue light is essential for the vegetative growth of the leaves of plants whereas combination of red and blue light promotes flowering in plants. There are certain plants which require less light for their growth. In such cases, light can be filtered using protective shelters so that the plants are exposed to minimum required amount of sunlight. The more sunlight a plant receives, the higher will be its photosynthetic rate.  However, leaves of plants growing in low light readily excoriate when moved to a bright location having intense sunlight.  Over time, as the wax content on a leaf increases and the plant grows it becomes more sun tolerant. When starting indoor transplants, generally plants are given 12-14 hours of light per day. Plants are generally intolerant to continuous light for 24 hours.