how to use grow lights

How to Use Grow Lights for Plants – Best Tips and Tricks in 2022

Employing the imagery and the mythological symbolism of Icarus in the context of plants, being too close to the sun, in its real or artificial form, is a dangerous thing.

One of the prerequisites for growing healthy plants is adequate sunlight which takes part in the process called photosynthesis.

However, sometimes the natural exposure to sunlight that a plant receives is insufficient. In that case, using grow lights is advisable to supplement the light exposure and simulate daylight.

This article is a comprehensive grow light guide in which you will learn:

  1. What lights to use for indoor growing
  2. How to use grow lights for indoor plants
  3. DIY grow light stand
  4. Answers to frequently asked questions

And a lot more tricks and tips for successful indoor gardening.

Related: Plant Lighting- Guide for Gardening Beginners

How Do Grow Lights Work

Grow lights are a supplementary, artificial source of light. Their function is to replicate the effect that the sun has on plants and contribute to the process of photosynthesis. Without it, the plant’s growth and flowering will begin to slow down.

It makes no difference to the plant whether the light is natural or artificial, which is how growers are able to produce flowers on certain plants such as azaleas outside their growing season.

In addition, using a grow light can help growers to manipulate the plants’ day and simulate natural daylight.

Finally, growing plants under lights can prevent phototropism, a situation in which a plant receives the sun from one direction only and leans towards it as a consequence.

Choosing the Right Grow Light

Before we discuss how to set up and use grow lights, we should first delve into how to choose the right lights.

The type of plants you are cultivating (flowering or non-flowering) and in what room in your house play a significant role in determining what the best light for growing plants indoors is.

In the living room or the sunny bedroom, they will receive lots of bright light. However, in the attic or the basement with not a single window, plants will barely survive, hence they need more hours of supplementary light per day.

Moreover, in order to decide what type of light is best for your indoor plants, you need to consider some other factors, such as:

  • Quality of light or the color spectrum. Plants use red light which helps them form flowers, and blue, thanks to which leaves grow healthy and compact.

For instance, fruiting plants set more fruit if provided with light from the red end of the color spectrum and so do flowering plants, while leafy green plants prefer the white and blue end of the light spectrum which stimulates foliage growth.

To present the wavelength in nanometres, use 700-600 NM infrared, a warmer-red end for good flower growth, such as red LED lights.

On the other hand, use 500-400 NM ultraviolet, a cooler-blue end for good foliage growth. These lights include warm white or cold white fluorescent lights, metal halide and blue LED lights.

  • Intensity or how much light a plant is exposed to on a daily basis
  • Duration or how many hours of light a plant is exposed to during the day
  • The size of your growing space and how many plants are lit by one source of light
  • Purpose – are you using grow lights for that purpose solely or a decorative one, too
  • Versatility – integrated or adjustable lights
  • The maturity of the plants – determines the best type of light, the preferred distance between plants and lights and the required hours of exposure per day

Types of Grow Lights

types of grow lights

Considering the aforementioned factors will help you determine the best grow light for your indoor plants. The options available are presented below.

1. Incandescent lights

Incandescent lights are your typical light bulbs with a wire filament enclosed. Although they are inexpensive, they are short-lived and not particularly efficient since the highest amount of energy is emitted in the form of heat.

Another disadvantage is that they can encompass only few plants grouped together depending on their size.

Because incandescent lights give off a lot of heat, they must be moved further away from the plants.

Although they help the plants form blooms, they do not do much for leaves.

2. Fluorescent lights

Fluorescent lights are the most common grow lights for houseplants. Their light spectrum is cooler than in the case of incandescent lights and they encompass a wider spectrum of light.

Pair a cool white light bulb with a warm one to provide your plants with both red and blue light that is needed for bud and leaf development.

You can also find a full-spectrum bulb and pair it with a regular one for your plants’ optimum growth.

3. LED lights  

LED lights are smaller, more efficient than fluorescent lights and, although they seemingly cost more, they are indubitably cost-effective in the long run because they save energy and emit less heat.

They come in both red and blue, but the growing area will consequently turn pink and some plants make less appealing displays than others under LED lights.

LED lights are nowadays available in white, which ensures that your precious plants get both color spectum for optimum growth.

Related: LED Grow Light Strips For 2022 – 8 Best Products and Guide

How to Use Grow Lights – General Setup

Now let’s see how to set up grow lights for indoor plants.

After choosing the most adequate source of light for your needs, make sure that the area where you are going to place your plants is squeaky clean.

Only then is it time to set up your grow lights.

The gooseneck lamps are extremely practical because you can easily move them around.

Attach the preferred bulb into the lamp and install it either in the wall above the plant, on stands or grow light shelves. Make sure that the lamp does not break and fall, so install carefully.

You can also buy grow light shelves in different sizes with LED lights installed. Since they tend to be expensive, you can make your own plant light stand.

Adjustable Grow Light Stand DIY

The first step is to design your adjustable grow light stand. You can get many ideas on the Internet and let your imagination run riot to make it aesthetically pleasing and match your surroundings.

You should think beforehand what plants you want to grow under grow lights so that you can take measurements and make the stand long and wide enough.

To make your own light stand, you can make use of an old shelf and dismantle it to get the material you need or buy new wooden planks.

Before you start, measure each plank and make sure every part fits in.

Make identical holes on two planks that will make the right and the left side of the stand so that you can move the third plank that goes straight across upwards as your plants grow.

This plank should have the light tube attached to it.

Next, you need to install the light tube, ensuring that it is at a proper distance from the plants.

Viola! There you have your own light stand. Simple and inexpensive.  

Grow Lights Positioning

The light levels at the center of the bulb or tube are higher than at the ends, which can easily damage your plants and burn the foliage, especially if the lights are too close to the plants.

To prevent that, you need to position your grow lights at a reasonable distance from the plants. But, how far away exactly?

As far as fluorescent lights are concerned, the flowering plants should be positioned 16-30 centimetres above the plants, while foliage plants should be positioned at least 30 centimetres from the plant to around 75 centimetres.

Besides, the maturity of your plants determines the preferred distance from the lights. In case you are cultivating seedlings and young plants, position the lights further away from the plants if you are using strong UV light.

However, fluorescent lights and tubes give off very little heat and can be placed closer to seedlings.

LED lights can be positioned at a larger distance from the plants so that taller plants have enough space to grow under them.

In the case of some hardy species, grow lights can be placed a little bit closer.

Repositioning Grow Lights

repositioning grow lights

At one point, you will have to reposition your grow lights when your plant has grown to a certain extent.

To do that, you can raise the gooseneck lamp up higher by the neck.

Fluorescent lights can be adjusted up or down so that they can be kept just a few inches above the plants growing below, which is especially important when starting plants from seed.

Important Considerations

  • The plants you are growing under lights must be similar in size.
  • Using a timer to make sure that your plants receive the same amount of light every day.
  • Use a reflector that will direct light from your source toward the plants and they can concentrate the light onto one or two plants. Reflectors can also block natural light and are best used for heat-loving, high-value plants like orchids.
  • Regularly dust your lights and fixtures
  • If your lights are on for at least 10 hours each day, they will emit more heat and damage temperature-sensitive plants, which will also need more water. Install ventilation or use blowing fans in the vicinity to decrease the temperature.
  • Use mirrors to reflect light and when repainting the room you are growing your plants in, make sure that the color is light, ideally white. 
  • Be watchful of any reactions your plants might show. Experiment with different spots until you find an ideal one that will provide your plants will just enough light.

Frequently Asked Questions

How many hours should you use grow lights?

As well as the intensity of light, the duration of the light is also important.

As a general rule, young plants and seeds that have germinated need at least 12 hours of light per day and 8 hours of darkness, with the amount of light increasing as they grow to 14 hours per day.

On the other hand, mature plants will perform well with 8-12 hours of light per day.

Besides, take into account the type of plant and its needs. For example, flowering plants demand longer periods of light to form buds.

There are long-day plants that need at least 12 hours of light per day and a short night, whereas short-day plants demand long nights of at least 12 hours and short days in order to form blooms.

Some plants, which are called day-neutral, are flexible and you need to provide them with equal hours of dark and light.

To make a sound decision, take into account the type and the maturity of the plant, the conditions in its natural habitat, the climate in your area, and the amount of natural exposure to the sun that it receives.

Should you run your grow lights at night?

Many growers run their grow lights at night for different reasons. In case your plants grow in the basement or the attic without any source of light, turn the grow lights at night by all means.

The plants’ night will become day, so observe if the plants exhibit any undesirable changes.

However, if your plants are growing in a light position during the day, they need a certain period of darkness and too much light might damage them, depending on how much light they are able to tolerate.

Be aware of how much light your plants can tolerate and act accordingly.

Can you leave grow lights for 24hrs a day?

This is not advisable since most plants need certain periods of darkness to develop buds and flowers. Some need only a limited amount of sun and prefer to grow in the shade most of the day.

Besides, too much light interferes with the proper development of the plant, so it will not develop properly and its growth will be hindered.
For that reason, you should provide enough bright and dark periods. Make sure you are aware of the needs of the plants in your care.

Can too much light kill a plant?

Leaving your grow lights on for the entire night will not kill your plant if it happens to you once, but doing it regularly will stunt the growth, hinder the flowering process, scorch the plant, burn foliage and eventually kill the plant. Being knowledgeable about how much light your plants need and how much they can tolerate will prevent this.

Can plants live only with artificial light?

If possible, make sure to provide your plants with at least the minimum amount of the recommended exposure to the sun, depending on their individual needs.

If that’s not possible and you can only rely on artificial lights, make sure to choose plants that tolerate low levels of light as your houseplants and plants that can grow in the shade.

These plants can survive if grown only under grow lights, which is not necessarily the case with sun-loving plants.

What type of light is best?

Think of the quality (color) of the light you need, intensity, duration, maturity and the type of plants you are cultivating.

Fluorescents lights are the most common grow lights for houseplants, ideal for seedlings, affordable and they encompass a broad spectrum of light.

On the other hand, LED lights seem more expensive but are energy and cost-efficient in the long run.

Regardless of which one you choose, ensure the proper distance between the plant and the lights. You can experiment with both types of lights and observe to see to which one your plants react better.

When should you change grow lights?

Change fluorescent lights yearly, since their light intensity gradually decreases and the ends of the tubes turn black. LED lights last extremely long, while the duration of the incandescent lights is the shortest.

Are there any safety considerations to bear in mind?

Make sure to follow the manufacturer’s guidelines when installing grow lights and do it safely. Getting waterproof lights is advisable if you are cultivating plants under lights in a greenhouse. As with any type of UV light, grow lights can be damaging to the eyes and may cause instant headaches.


Using grow lights is a great yet affordable way to simulate natural daylight and enhance your plants’ growing and blooming process.

It compensates for the lack of natural exposure to the sun. Now that you have learned how to use grow lights for indoor plants, your plants will be grateful and you will see it by the way they are looking, luxuriant foliage and exquisite blooms.