How many hours of artificial light do plants require per day?
This varies with the plants and the season of the year. In general, plants require a total of twelve to eighteen hours of light a day to bloom. Therefore, you need electric light only long enough to make up the difference between the total light squired by a plant and the length of the day. For instance, if you are growing gloxinias, which require a total of about fourteen hours, and if in January daylight lasts only nine hours, keep the fluorescents on for five hours.
We are sorry this answer was not as useful for you as it could have been.
Help us get better!
Will you tell us how we can improve this answer?