What is a Plant Grow Light?
Plant Growth
Plant growth processes involve the use of light, carbon dioxide and water to manufacture food for the plant’s use. And while soil nutrients help to fortify plant structures, light is an essential component in producing actual food for the plant. Photosynthesis processes enable plant organisms to produce needed food supplies. Photosynthesis occurs when plant leaves absorb the energy contained inside light. This energy becomes the fuel used to manufacture glucose, or sugar molecules. Plants are typically most responsive to light that falls within the sunlight ranges. Blue and red light, which plants absorb, have the greatest effect on plant growth. Blue light is responsible primarily for vegetative (leaf) growth. Red light, when combined with blue light, encourages flowering
What is a Plant Grow Light?
A grow light or plant light is an artificial light source, generally an electric light, designed to stimulate plant growth by emitting an electromagnetic spectrum appropriate for photosynthesis. Grow lights are used in applications where there is either no naturally occurring light, or where supplemental light is required. For example, in the winter months when the available hours of daylight may be insufficient for the desired plant growth, lights are used to extend the time the plants receive light. If plants do not receive enough light, they will grow long and spindly.

How does the light affect plant grow?
The following aspects of light affects both plant growth (photosynthesis) and plant development (morphology): light intensity, total light over time, light at which moment of the day, light/dark period per day, light quality (spectrum), light direction and light distribution over the plants.
So to use the plant grow light in a proper way is crucial.
Tips:
Growing trees, flowers, vines or other types of plants requires knowledge of a plants' needs. While different species and types of plants require different growing conditions and treatments. The factors that will affect plants growth are: soil, water, light, air, temperature, humidity and insects. To cultivate your plant well, you need to consider all of those factors.