Blog Indoor Plants How To Use Grow Lights For Indoor Plants

How to Use Grow Lights for Indoor Plants

@Kiersten avatar
Kiersten Rankel
Dec 30, 2021

It’s true that there are numerous plants you can keep healthy in an indoor environment with only natural light to nourish and sustain them. 

However, sometimes natural light can be limited in your home depending on the type and number of windows you have, which means that your plants may not always get the level of light they need to flourish. Since you obviously want your indoor plants to grow just as well as your outdoor plants, sometimes a little lighting help is required. 

Enter interior grow lights into the picture! Indoor grow lights make gardening and growing healthy plants in your home easier than ever before, allowing you to tend to and grow your favorite plants all year long.

What are Grow Lights?

All plants work on the principle of photosynthesis, which is the process of converting light energy into food, using chlorophyll. However, chlorophyll doesn’t absorb the whole spectrum of sunlight. It actually absorbs only the red and blue light spectra. 

This means that in essence, plants don’t truly need sunlight to grow––they just need red and blue lights! This is where grow lights come in. 

Grow lights are basically electric lights used to mimic the effects that natural sunlight has on plants. 

Depending on the type of grow light, they can feature a light spectrum closely resembling the spectrum of natural sunlight, or they can provide an alternative spectrum that is optimally designed to fulfill the needs of a particular type of plant. 

In areas where there isn’t a lot of sun especially, grow lights are popular. They are used to ensure healthy plant growth, and are used with varying colors, spectral outputs, and temperatures to match the natural effects of sunlight as much as possible. 

Grow lights come in a variety of spectrum ranges, lamp intensities, as well as color temperature options to suit the different needs of a plant through the different seasons. They can be used either to supplement sunlight, or even used to replace it completely. 

One thing to note about using grow lights is that they may attract bugs or spider mites. Learning how to get rid of spider mites and other pests is important to keeping your plant healthy and thriving.

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Types of Grow Lights 

Fluorescent Light

Fluorescent light is a specific type of light created by harnessing the energy of charged gas. These are considered a second generation light source. Inside a fluorescent tube, gas and mercury vapors combine together to create a chemical reaction that results in producing a UV light inside the tube. 

These fluorescent tubes are pre-coated with phosphor, which is what creates that white fluorescent light. Fluorescent tubes are available in different intensities and levels of power. These light tubes are thin and easy to fit into small places. However, they require a standing ground or stand for stability, as well as a ballast to regulate the current and prevent shorting. You can also use compact fluorescent lights (CFL) with the same effects.

  • Fluorescent lights in general––and CFLs in particular––emit high doses of red and blue light spectra, making them a great candidate for use as grow lights. Additionally, they have a comparatively long life span, use little energy, and fall into an easily affordable price range. 

The biggest advantage of fluorescent lights however, is that they don’t release a lot of heat. That means you can put them close to the plant, without risking damage to the leaves. 

High-Intensity Discharge (HID) / High-Pressure Sodium (HPS)

High Intensity Discharge lights are an efficient source of lighting, with a high light output. Considered to be a third generation light source, HIDs come in a variety of types including metal halide, mercury vapor, and high pressure sedum lights. However, out of all these, the HPS light output spectrum most closely resembles that of the sun. 

  • HPS emits a light spectrum in the yellow and red range, along with a small portion of blue and other visible lights. Because of the higher red light spectra content, HPS grow lights are ideal for blooming and fruiting of plants. 

However, HPS grow lights can emit some heat as well. That means they can’t be placed close to the plant. Additionally, HPS are a more costly option and may require an initial investment to set up, especially if you plan to use them on a larger scale than just a room in your home. This is largely due to the fact that you may also need a heat management and ventilation system along with an HPS. 

Photo by Bigshe64

Light Emitting Diode (LED) 

LED lights are made up of multiple light-emitting diodes, all combined together in a sturdy casing equipped with built-in fans and a heat sink to prevent overheating and damage. 

LED lights are convenient to use and don’t require a ballast for connection. In the case of LED grow lights, different colored LEDs are combined together to cover the whole spectrum of growing lights. 

For this reason, LEDs are known to produce the highest levels of photosynthetically active radiation, thereby making them one of the most efficient types of grow lights you can use indoors. 

  • Granted, LED lights provide the whole spectrum of light to ensure plants get a balanced level of exposure to red and blue light spectra. However, specific grow lights can be used for plant therapy, with a focus on the red and blue lights, plus supplemented by green light spectra for an added benefit. 

These types of lights don’t emit any heat at all and can be placed near your plants safely, although that might not be necessary since they don’t lose intensity with distance. However, they can be on the expensive side. That’s something you’ll have to weigh against the benefits of their longevity and efficiency. 

How to Use Grow Lights for Indoor Plants

Not only can you use grow lights to stimulate and boost the growth of your indoor plants, you can also use them to intensify and enhance the blooming and fruiting of your plants.

For Seeds 

Did you know that grow lights can be used to stimulate the production and consequent growth of seedlings for your indoor plants? Seedlings require extra energy to kick start the growth process; this energy can be harnessed by using grow lights. Your best bet is to use LED bulbs or fluorescent tubes, with full spectrum lights. 

For Herbs

If you enjoy growing herbs indoors, you can use grow lights to keep them going all year long, including during the winter season. For this specific purpose, you might want to use grow lights that focus more on the red light spectra, as red lights help to boost flowering. 

Photo by Dido

Other Factors to Consider When Using Indoor Grow Lights

Placement & Distance

How much distance should there be between your plants and any grow lights? We touched on this topic above while talking about the different kinds of grow lights. However––in most cases––hanging grow lights above your plants is the most efficient way to go. That way you’ll be sure that you are providing light to all sides of the plant, without placing the lights so close you risk harming them.


How long should the grow lights stay on? This is an important consideration that may require some tweaking as you perfect your use of grow lights. 

To grow seedlings, it's best to leave the lights on 24/7, whereas for flowering plants, 16 hours a day should be enough. For other indoor plants, grow lights should be switched on for an average of 12 hours a day, but you decide when!

Learning how to utilize grow lights for indoor plants is a key skill for all plant-lovers to learn. Though you may not have any plants indoors yet, eventually you will and learning how to use grow lights to assist them can make a world of difference in how well your indoor plants survive and thrive in your home. Sometimes, relying on natural light just isn’t enough, especially if you’re trying to grow an indoor garden that you can access and enjoy year round. 

Looking for more tips on plant care? Check out our latest guides on the best fertilizer for indoor plants, how to repot indoor plants and the top safe plants for dogs and cats!