The specific needs of plants determine which lighting is best for growth. Artificial light must imitate the natural light that plants are most suitable for. If a plant does not get enough light, it will not grow, regardless of other conditions. For example, vegetables grow best in full sunlight and flourish indoors. They need the same high level of light. Leaf plants (such as vines) grow in shade and can grow normally in lower light levels.
The use of plant lamps depends on the stage of plant growth. Generally speaking, it is recommended that plants receive 16 hours of radiation and 8 hours of rest during seedling/growth stage, 18 hours of rest during nutritional stage and 12 hours of rest during flowering stage.
In addition, many plants also need darkness and photoperiod, which is called photoperiod to trigger flowering. Therefore, the light can be turned on or off at a set time switch. The optimum proportion of photoperiod depends on the type and species of plants, because some prefer long and short nights, while others prefer the opposite or medium length of day.
In discussing plant development, great importance is attached to photoperiod.
Plants responding to photoperiodic flowers may have facultative or specific responses. Part-time response means that a plant eventually runs out, regardless of how the photoperiod is spent growing faster in a given photoperiod. Professional response means that plants will flower only when they are planted under certain light conditions.