How long should the plant growth light be on?

Different types of plants require different amounts of light. As a general rule of thumb, most vegetables and flowering plants require 12 to 16 hours of light per day, and flowering plants are at the top of this range. Plan for most plants to have at least 8 hours of darkness per day.

Darkness is actually very important to the plant growth cycle. During the day, sunlight helps plants produce energy through photosynthesis. However, at night, plants break down this energy in a process called "breathing" to promote growth and flowering.

Check your seed packaging or plant label, or ask the nursery for specific advice. And make sure to turn off the grow lights every once in a while. No one likes to work 24 hours a day-even plants!