Grow Lights — How to Use Them Well

• The best grow lights for plants supplement weak natural light rather than replace it.

• The setup, timing, and intensity matter as much as the type of grow light you select.

• Deciding between fluorescent and LED depends on your plant and its needs.

A bathroom without a window.

Natural light, but no direct sunlight.

An eastern-facing window that gets plenty of direct sun in the summer, but barely any in winter.

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

In all of these situations, your plants can flourish when you know how to use grow lights. They can be a fantastic tool for your indoor garden, but researching them can leave anyone blinded by watts, kelvins, and the misused term ‘full spectrum.’

Here’s what you need to know, without the technical jargon. And for personalized guidance, the team at Tula House is always happy to help you pick out the best grow lights for your plants.

Using Grow Lights Well: Why, Where, and How

Why Should I Use a Grow Light?

Soil and water are important. But all plants also need light to live. So if you want to have a plant in a room with no windows, you’re going to need a grow light.

However, even buying the best grow lights for plants does not guarantee all your problems will be solved. Attempting to grow a plant that thrives on lots of light — like a cactus — in a room with just a grow light and no other light source may prove difficult.

Where Are Grow Lights Useful?

It’s hard to replace the sun, but that doesn’t mean it can’t be done.

Grow lights for plants work best when used to supplement the 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.

How Should I Use Grow Lights?

Setup

How you position your grow lights depends on your plants’ needs, but here are some general guidelines.

• Distance: The grow light should sit 6-12 inches above the plant.

• Placement: The light should sit directly above the plant, not off to the side, to prevent leaning.

• Coverage: The entire plant should get light, not just the top leaves.

Timing

Plants, like us animals, have circadian rhythms that they need to keep to. You can see it in prayer plants like Calathea, which have open leaves during the day and closed leaves at night, or Epiphyllum oxypetalum, which only blooms at night.

Here’s how long grow lights should stay on:

• Low-light plants: 8-10 hours

• Medium-light plants: 10-12 hours

• High-light plants: 12-16 hours

Keep grow lights on up to 16 hours a day, max. Some models even come with built-in timers.

Visit us at Tula House, and we can help you understand your specific plants’ needs and how to use grow lights to do right by them.

The Best Grow Lights for Plants

Choosing the ideal grow light for your indoor plant begins with understanding your options.

Do I Need a Full-Spectrum Light?

Full spectrum, in short, means light output that closely mimics the light output of the sun. This means the wavelengths of the artificial light are similar to the wavelengths of the sun, which is how full-spectrum lights 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 for the term. Instead of seeking out a light that mimics the sun, the best grow lights for plants provide the exact kind of light (intensity, wavelengths, duration) they need. 

Fluorescent vs. LED: Which Are the Best Grow Lights for Your Plants?

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

Fluorescents

These tend to be inexpensive, easy to install, and sufficient for a wide range of plants. Think office ceiling lights — there may be no windows 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 for plants are an excellent choice.

Fluorescent grow lamps should not be used as a full sun replacement for plants that require a lot of light, like cacti and succulents. They also contain mercury, a toxic chemical. Part of understanding how to use these grow lights is after-care and disposal — it’s important to seek out proper recycling methods and providers.

LEDs

These are fantastic if you want to provide a specific type of plant with 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 they last longer, are more energy efficient, and are 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 receive.

Tula Recommends

Fluorescents can be the best grow lights for low-light 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 are the best all-around grow lights for plants, since they 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 Euphorbia 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 situations and everything in between, making them a simpler solution when you’re trying to figure out how to use grow lights. 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 yours home!