4 Tips for Buying and Using Grow Lights for Your Houseplants, According to a Plant Pro

Winter is here, y’all. The days are shorter.  The early darkness can sometimes make you feel a little down, and the same goes for your plants. Maybe you moved your plants inside for the winter or you’ve been noticing your plant that was so happy by the window is now showing signs of sadness. While there are certain changes you should make to your plant care routine in the winter, it might also be a good idea to invest in some grow lights.

“Light is a big stumbling block in my opinion,” says Shane Taylor of Moss & Timber in St. George, Utah. “Nowadays, you can set reminders to water, so it really comes down to putting the plants in enough light for them to sustain themselves.”

Taylor says he loves high-light plants such as cacti and succulents but knew they needed more light than the sunlight they were getting in his current space.

“We started experimenting with basic LED bulbs, because I don’t like the rave-like look you get from a lot of the grow lights, and we had a fair amount of success just with off-the-shelf-from-the-hardware-store LED bulbs.”

Since then, Taylor has become somewhat of an expert on grow lights, even advising Mandi Gubler of Happy Happy Houseplant. He says there are four things to keep in mind when selecting grow lights: directionality, intensity, color temperature and broadness of spectrum, and duration.

But first, which grow light is right for your plant? Here’s a look at the top three grow lights you can find on the market today.

1. These are less popular than HID and LED grow lights, but they are a good, cheap option. If you’re just growing a couple of plants and looking for supplemental light, a regular ol’ CFL can work.
   
   If you have enough plants to warrant getting a tube, a T5 can be a good option. These are also good for starting seeds or growing herbs. The light intensity is not very strong, so the plant likely won’t flower under this kind of light, but it’s better than no light at all.

Fluorescent grow lights and LED lights won’t burn your plants, so you can hang them fairly close to your plants without fear.

An LED Grow Light is the most popular option for many reasons: It consumes very little power and produces very little heat, and it lasts a long time. That means you can provide some supplemental light for your plants while remaining relatively unbothered in your space.

Also, you can adjust some LED Grow Lights to show more red or more blue light depending on your plant’s needs (blue light promotes foliage growth, while red light promotes flowering).

GE has a bulb made specifically for grow lights, and Home Depot has a wide range of LED grow light bulb and tube options.

If you start going down the grow light rabbit hole, you’ll find a lot of research on these ultra-bright and very effective grow lights. But for the average houseplant owner, you are unlikely to need the HID option—they’re far more intense than is required for your collection. You do not need an HID grow light for your fiddle leaf fig. I repeat: You do not need an HID grow light for your fiddle leaf fig!

Now that you have a better idea of which light you might want, here are Taylor’s tips for success.

Which direction is the light pointing? Taylor explains that a bright bulb that’s putting light out at 360 degrees is not so helpful for your plant right under it, because it’s not going to be getting that light.

“I gravitate toward spots and floods and fluorescents with the reflector that bounces the light toward the plant,” says Taylor. “Direction makes a big difference.”

For best results, go with spots or flood LED lights, instead of omnidirectional bulbs.

Taylor explains that the intensity of light is directly linked to the distance of the light from the plant, and that the further away you move the light from the plant, the intensity will weaken exponentially.

So you may have a bulb with a high number of lumens—meaning it emits intense light—but if the bulb is too far away, it doesn’t really matter because the plant is receiving a much smaller amount of light from it. 

If you have many plants with different light needs, you can use this to your advantage without buying a wide variety of bulbs. Some high-intensity bulbs can be placed higher overhead for your lower-light plants, and you can add in supplemental lighting closer to plants such as cactus or succulents that need much more light.

If you have a high-light plant, place an intense light closer to it. If you have a low-light plant, move your intense grow light farther away from it.

“Fluorescent and traditional bulbs usually beat LED bulbs in this category because they have way more spectrum,” says Taylor. 

He says when looking at your bulb information, a good grow light will have a CRI that’s close to 100.

Instead of worrying about Kelvin numbers as well, Taylor says to look for bulbs that say “daylight” or “sunlight” on the packaging.

“That should be better balanced and more in the spectrum that’s useful for plants. What that equals is basically 4500 Kelvin or up to about 6500 Kelvin,” says Taylor.

How long do you leave your grow lights on? Well, that depends on the intensity of the grow light and your plants’ needs. 

“You can make up for lack of intensity by having lights on longer,” says Taylor. 

So if you have a lower-intensity bulb or you have a higher-intensity bulb that’s far away from your plant, leaving it on longer (12 to 16 hours) can be almost equally beneficial to the plant as having a high-intensity bulb on for eight hours.

While there’s no research that says your plant shouldn’t receive light for 24 hours a day, Taylor suggests still giving your plant the night off from its grow light to better mimic nature. 

Implementing a grow light system in your home is going to require a little bit of trial and error and a little bit of intuition. Start with one or two, play with the distance from your plants, and see how they react.

But here’s the most important question I had for Taylor: Can grow lights be cute or do you have to put them in the standard aluminum fixture with a clamp?

“They make very specific grow light bulbs that will fit in most standard outlets, so you can get a nice decorative floor or table lamp, outfit it with the right bulb, stick a timer or smart plug on it so that it goes off and on automatically, and you’ve got yourself a perfect, stylish growing setup,” says Taylor.