Indoor gardening and light troubles go hand in hand. Often, our wildest plant dreams fizzle when we encounter the reality of one factor: light exposure. But that doesn’t have to be the case!

A bathroom without a window. Natural sunlight, but no direct sunlight. An eastern facing window that gets plenty of direct sun in the summer, but barely any in winter. In all of these situations, your plants can flourish with the help of grow lights.

Grow lights can be a fantastic tool to bring to your indoor garden, but researching them can leave anyone blinded by watts, kelvins, and the erroneously used term ‘full spectrum’. Here’s what you need to know, without the technical jargon.

When should I use a grow light?

All plants need light to live, so if you want to have a plant in a room without windows, you’re going to need a grow light. However, getting a grow light does not guarantee all your problems will be solved. Attempting to grow a high-light loving plant like a cactus in a room with just a grow light and no other light source may prove difficult, depending on the light you buy.

It’s hard to replace the sun, but that doesn’t mean with the right light set-up it can’t be done.

Overall, grow lights work best when used to supplement natural light a plant is already receiving. If that cactus is in a window that faces east and doesn’t get much direct sunlight, a light could help. Or, if a Monstera doesn’t get any direct sunlight in its northern facing window, a grow light could lead to more erect growth and larger leaves.

 

What does ‘full spectrum’ mean?

Full spectrum, in short, means light output that mimics as closely as possible the light output of the sun. This means the wavelengths of the artificial light are similar to the wavelengths of the sun, and for that reason provide plants with the necessary energy to thrive.

That said, ‘full spectrum’ is a rather dubious term in artificial light sales, since there is no industry standard technical designation. Instead of seeking out a light that mimics the sun, it’s best to seek out a light that provides the kind of light (intensity, wavelengths, duration) your plants need. 

Should I keep grow lights on around the clock?

Plants, like us animals, have circadian rhythms that they need to keep to. You can see it in prayer plants, which have open leaves during the day and closed leaves at night, or the Epiphyllum Oxypetalum, which only blooms at night. Keep grow lights on up to 16 hours a day, max. Some models even come with timers built in. 

Fluorescent vs. LED.

There are two main kinds of grow lights on the market.

Fluorescents tend to be inexpensive, easy to install, and sufficient for a wide range of plants. Think office ceiling lights. No windows are nearby, but the snake plant, rubber tree, money tree, and Dracaena are thriving. For these kinds of plants – the less picky the better – fluorescent grow lights are an excellent choice.

Fluorescents should not be used as a full sun replacement for plants that require a lot of light, like cacti and succulents.

Fluorescents also contain mercury, a toxic chemical. When disposing of these lights, it’s important to seek out proper recycling methods and providers.

LEDs are fantastic if you want to provide a specific type of plant everything it needs to thrive.

Often LEDs can be used as a full sun replacement for plants that require a lot of light.

They are more expensive upfront, but last longer, are more energy efficient, and more environmentally friendly, than fluorescents. Manufacturers also design LEDs to be adjustable in intensity and light spectrum. This is why you often see LEDs of different light intensities or colors. Different plants require different light pigments, and many LEDs allow indoor gardeners to adjust the amount of green, blue, and red wavelengths their plants are receiving.

 

Tula Recommends

 

 

Fluorescents tend to be a great fit for low-light tolerant plants that aren’t near any windows at all, or high-light plants that are getting some direct sun, but need a little extra help. Agrobrite Agrosun CFL is an excellent example of an inexpensive and modular fluorescent grow bulb. It can fit right into a normal pendant or lamp socket.

Take one home.

 

 

LEDs can be adjusted to fit pretty much any light situation you require. Your philodendrons in the corner might need an ambient glow throughout the day, or the new cactus in the north-facing window might need several hours of direct sun that it isn’t receiving now. The right adjustable LED can help with both of these situations, and everything in-between. The Rousseau Sparrow Hawk pendant light has a telescoping beam that can focus directly on one or two high-light plants or expand to provide ambient light for a large indoor area.

Take one home.