There's a right way and a wrong way to use grow lights (and no, we're not talking about *that* way)
. “But when the sun goes down, plants’ opportunity to eat disappears and other physiological processes take over, including energy metabolism and growth.”
While you probably don’t want to leave your grow lights on indefinitely, you also don’t need to match the short winter daylight hours. John Morse, director of horticulture at, lets his houseplants bask under grow lights for between 15 and 18 hours a day. Pollak, meanwhile, suggested a minimum of 12 to 14 hours for my succulents on overcast days. Following that advice, I’ve started turning my grow lights on at 7 a.m., when I wake up, and off around 9 p.m.
Your use of grow lights will depend on your latitude and what kind of plants you have. And if you haven’t already acquired some, consider adjustable lights, so you can move them away as the plants grow. Doing so is especially useful if you’re trying to germinate seeds, as Pollak often does at the Chicago Botanic Garden.
However you use them, grow lights give you power over a fundamental force of nature. And, of course, the ability to keep your succulents alive on your windowsill over the winter.