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How To Use Grow Lights For Indoor Plants? (A Complete Guide)

Grow lights populate in the house plant community for more than one reason. Whether your house doesn’t get enough light, or it is the winter season, or the plant species requires more light than it gets, grow lights are your solution. 

So, in this article, we shall discuss how to use grow lights for indoor plants. Right from types of light, light intensity, installation, and best grow lights to choose from, we have got everything covered for you.

Grow lights are placed 12-24 inches above most houseplants to mimic natural sunlight. These lights are available in various intensities and sizes to provide ample light for the indoor plants to thrive. Use them for at least 8-10 hours daily for the plants to absorb the most amount of light.

If your indoor plants are showing signs of problems that are caused due to low light, consider getting grow lights for them. This article will provide the information you need about grow lights and how these can help your indoor plants.



How long should I use grow lights on my indoor plants?

Most newbie gardeners think that their beloved houseplants don’t need much light for their nourishment. This is nothing but a misconception, and it may affect the plant’s lush and leafy growth. When you cannot provide enough natural light to your houseplants, grow lights will come to the rescue.

First, you need to find out how long your plant can endure these grow lights without harming itself.

On average, a standard healthy plant needs a minimum of 8-10 hours of light. Depending on certain conditions, it may even take up to 16 hours.

Exposing your houseplant to the extremely long hours of sunlight increases the rate of photosynthesis. And that leads to the evaporation of moisture that the plant stores in its leaves.

Leaves become dry, and ultimately the plant experiences stunted growth or even death in extreme cases. That’s why darkness is also essential for houseplants.

Ensure you put off the light at night to allow your indoor plant to break down the energy stored during photosynthesis. Botanists call it-respiration. It is vital for houseplant’s average growth and flowering.

It would to always place the grow lights right above the houseplant. This is because we know the plant has a normal tendency to lean towards the source of light, be it natural sunlight or artificial. And if it leans, you will have to experience the adverse effect of using light instead of utilizing it.

The other thing you should take care of is the heat of the grow light. Maintain a sound distance between the plant and the grow lights so that the latter’s heat doesn’t touch the former.

And the last thing is to use the luminosity of the grow light as per the houseplant’s size and requirements. For example, the houseplants are either bit shed-loving or smaller in size, prefer LED lights having color temperature around 4000 and 6000 kelvin. 

You can use LEDs of color temperature 6500 kelvin for a matured and average-sized houseplant. We will be discussing more on this for your convenience in the following section.

Also read: Do Indoor Plants Need Sunlight? (With 25 Examples)

What type of light is best for growing plants indoors?

Mostly, grow lights available in the market falls in the given category -Incandescent light, fluorescent bulbs, and LED, HID (High-Intensity Discharge) plant grow light. Each of them has pros and cons. 

Let’s have a detailed description to understand them more.

Incandescent light

These are the typical lights that are used around the houses. These are not usually used for indoor plants as there are better options available. 

Pros: Its cost is minimum among the three.

Cons: Power consumption is highest and gets very heated. That makes it unsuitable as an ideal grow light.

These can burn out fast if you use them on the plants for long and require more frequent replacement.

So I wouldn’t recommend you to use this one for your houseplant.

Fluorescent Light

These are far better than incandescent lights. However, it might not be very powerful.

Pros: Heat production is less compared to the previous one. Luminosity is acceptable as a grow light. You can opt for this one.

Cons: You cannot use it on a lot of plants at the same time.



LED light

Many LED lights are manufactured as grow lights for plants as these are ideal for plant growth. Light-emitting Diodes produce low heat and save energy.

You can set up a full spectrum LED light in your indoor garden.

Pros: It offers the least heat output, the ideal range of spectrum for houseplants, minimum maintenance needs, and the cost is least compared to the other two.

Cons: There are no cons as such.

HID light

HID lights or High-intensity Discharge Lamps are mainly commercial planters’ picks for a grow light. They are ultra-bright lights and highly expensive.

To sum it up, LED lights are the latest technology that provides you with a customer-friendly experience. And considering all benefits it offers, you must go for it.

The HID lights that emit more blue light are ideal for foliage and plant growth. On the other hand, the one that emits more red light is best for growing flowers and fruits.

What is the color spectrum in Grow Lights?

Color spectrum determines the warmth or coolness of the light, and you should choose the color spectrum that suits your requirements. The most popular colors that are given importance to are:

Red light: More red light means more stem and leaf growth. This can also regulate seed germination and flowering. The intensity range is 630-660 nm.

Blue light: Blue light helps leaf and plant growth, but it needs to be mixed well with other colors. Too much blue light can stunt growth, affect chlorophyll formation and leaf thickness. The range of intensity of this spectrum comes under the 450-520 nm range.

A grow light should have the complete range of the spectrum for better productivity of the houseplant. Most of the LEDs offer the whole range of it at an optimum price.

How to install a grow light?

The installation might vary on the type of light you are using and the number or type of indoor plants.

First, you need to determine the number of bulbs that will suit your plants and their light requirements.

Next, you will need a rack so that you can fix the bulbs over your plants. These are available online, so you can get one with an adjusting system that lets you adjust the height.

You can use a timer with the grow lights so that the plant gets proper light every day at the same time. Ensure that the air circulation is well around the plants as grow light can significantly increase the heat.

How effective grow lights are for indoor plants?

If your house doesn’t get much sunlight, and that doesn’t stop you from gardening and thinking of your houseplant’s better productivity, grow lights are the best option available to you. 

Grow light replicates the natural sunlight to the houseplants. And it also works as a substitute for natural warmth needed for the indoor plants’ better health.

Grow lights stimulate the process of photosynthesis, thereby helping houseplants to grow and flourish better. If you are using LEDs as grow lights, it also takes care of the ideal range of color spectrum for indoor plants.

For better effectiveness of grow lights, give a good think to its set-up. If you use an incandescent bulb, it should be at the height of a minimum of 24 inches from a houseplant because these bulbs might produce too much heat that may adversely affect the plant.

For fluorescent lights, the minimum gap between the light and the plant should be 12 inches least, and for the LEDs, it should be at least 6 inches. And you must place these grow lights overhead the plants so that all parts of the houseplant get equally illuminated.

To get the best results from grow lights, consider the size of your houseplant. Use one bulb if it’s small, and more for the bigger sizes.

Some of the best grow lights for your indoor plants are:

Can grow lights burn houseplants?

Grow light doesn’t burn your indoor plant, even if it is excessive. Instead, the heat associated with it does so.

But you can ignore the trouble with proper steps taken. With the right choice of light, proper set-up, and a keen eye on the houseplant, you can easily avoid the problem of burning leaves.

The first thing you need to care about is the distance to wattage ratio of the light. Be cautious about the exposure time of the houseplant to the light, as continuous lighting without a break may even kill your houseplant.

You should not use a regular bulb for household purposes as grow lights. There is a clear distinction that not all the lights are the grow lights because they emit too much heat and not the blue light.

The signs that your houseplant is getting burned from the grow light are the discoloration of leaves, wilting of leaves, and drooping.

But you may mistake it for a nitrogen deficiency. The thing that lets you differentiate between the two is that nitrogen-deficient leaves fall off, but light-burnt leaves don’t fall off easily.

The two things you should take care of are light intensity and duration of light. Now a question may arise in your mind that what is the light duration?

It refers to the number of hours of light that a plant receives per day. And if you want to know about the intensity, then it is the quantity of light per unit area, measured in Lux or foot candles.

Generally speaking, light intensity is what you need to focus on more. Let’s have a detailed discussion.

Light Duration

In most cases, your houseplants might be exposed to light for an indefinite amount of time and still show average growth. Average growth doesn’t mean your houseplant is healthy. 

However, exposure to light for a prolonged period adversely affects a plant’s growth cycle and ability to bloom. This mainly differs based on the type of plant. You will be amazed that plants biologically grow faster at night as all the essential metabolic processes mostly happen at night.

Not all indoor plants can trigger essential phases of growth or flowering without a good amount of darkness per day. These plants show photoperiodism.

Plants such as Poinsettias, Kalanchoe, and Christmas Cacti need extended periods of darkness for many weeks to start blooming and are given the name “short-day plants.” 

Therefore it’s evident that the duration of light may impact plant growth cycles, but no severe harm happens to them. 

Light Intensity

Light intensity is responsible for most of the adverse effects associated with a plant getting too much light.

When an indoor plant is kept under high-intensity light, a portion of this light energy is transmitted to heat. To dissipate this heat energy, you must spray water to cool itself off.

If you don’t take the measures at the right time, the plant will deplete its water reserves to cool itself and leave inadequate water for vital processes such as photosynthesis.

If the plant’s ability to cool off the heat is depleted or the amount of heat generated exceeds its ability to dissipate it, the plant will surrender to heat damage. This often comes as yellow or brown spots on the leaves and stems, normally yellow foliage, brownish crispy leaf edges or tips, or withered, dropping leaves.

High-intensity light can also make the soil dry. The plant may face inadequate moisture causing accelerated dehydration. It can spoil a plant in many ways since different plants have different endurance levels to light intensity.

Here is a small tip to save your plant from light burning. If you think your plant is at the edge of dying, shift it into more appropriate light and prune the damaged parts. You might be surprised to see the speedy recovery of your houseplants.

What should be the distance between the plant and the grow light?

The distance of the grow lights from your plants determines the intensity of the light and the width it covers.

When you are starting, keep the plants at a distance so that the strength is not too intense. In general, you can keep the plant a few feet away from the grow light.

When you place a plant too close to the grow lights, less width is covered. Therefore, if you are using the grow light for a single plant, you can place the plant close to the light, but if you have more plants, you will need to adjust the light and keep it further away.

How do you know your indoor plant is getting too much light?

It is not easy to predict how much light your plant truly needs. It can be direct, indirect, or low light as different plant species have individual requirements.

As mentioned before, a plant exposed to too intense light will eventually show signs of damage.

Noticing these early signs is important because it will empower you to adjust the positioning of your plant in such a way so that it can reduce lighting and solve the problem before your plant’s health is significantly affected.

The common signs that a plant undergoes when it becomes a victim of too much light are:

  • Brown leaves or tips
  • Brown, dry patches on the leaves
  • Leaves are turning either yellow or pale, particularly when exposed to the light for long. Discoloration of the leaves may not affect the leaf veins early.
  • Drooping and wilting, particularly of green new leaves.

Also read: Can indoor plants get too much light?



Final words

Indoor plants are delicate and need extra care from us. Grow lights are essential to provide sufficient light to let the plants enjoy healthy growth, and all its processes, namely photosynthesis, and flowering may go on hassle-free.

LEDs or fluorescent light covering the ideal spectrum range with a perfect intensity are good to go as grow lights. While using grow lights, maintain a particular gap between the lights and the houseplant so that the heat doesn’t affect the plant. 

Don’t forget to put the lights off at night because plants need rest like us. Even if you forget to do so, there is a way to save your plant. Look for yellow leaves in the plants. If there are any, make sure your plant is not experiencing a lack of nitrogen. If not, change the light and remove the damaged leaves.


Sources: University of MinnesotaDavid H. Trinklein, Horticulture State SpecialistThe University of GeorgiaThe Royal Horticultural Society.