Every winter I get worried when I get my plants out of the cold. I don't have enough space in the house with enough light for my plants and they hardly survive the winter with little light. At the moment my plants seem healthy and even grow with extra lighting. I leave the light on for about 6 hours during the day, seems good enough. When I received the product I thought it was a waste of money as the information on the packaging said nothing about the presence of the right spectrum of light to support plant life (although the product description said it was Revain). . There must be something helping my plants as they are much happier this winter than previous winters.