Updated at: 15-01-2023 - By: Sienna Lewis

There are two primary colors that are ideal for promoting plant growth: blue and red. Plants can thrive in almost every color of light, but the amount of each one is the most important component. Because they are near to the wavelengths that plants need, blue and red light are ideal for growing plants in a greenhouse.

Greens and yellows can also be added to plants for a more vibrant look. Additionally, the gardener needs to make sure that the greenhouse’s grow lights are of the correct color. After all, the control you have on the greenhouse conditions is its primary advantage, regardless of location and weather.

How To Choose What Color Light Would Be The Best For Growing Plants In A Greenhouse

In addition, plants might employ a little green and yellow in their designs. The gardener must ensure that the greenhouse’s grow lights are of the correct color, as well as the other greenhouse variables, such as temperature. Since greenhouse conditions can be controlled by anyone, regardless of location or weather, this is the fundamental advantage of greenhouses

What Light Color is Best for the Plant's Growth? - Plants Craze - Plant | Grow | Harvest

It is ideal to use red and blue lights to grow plants in a greenhouse since they absorb the most chlorophyll as a result of these hues. You should be aware, however, that the greenhouse might use a variety of lighting and color schemes. In a greenhouse, a full spectrum LED grow light is preferable to a blue or red light source.

Fluorescent lights vs. LED lights

Bushier plants will benefit from the usage of a fluorescent lamp that generates blue light. Because they don’t generate a lot of heat, fluorescent lamps are a fantastic choice for planting. One thing to keep in mind is that there are two types of fluorescent lamps: cool white and warm white, with the former having more blue in it.

Contrary to popular belief, LED lights do not use incandescent bulbs. Instead of fluorescent bulbs, you may more easily select the true color spectrum this way. A look at how colors affect plants will be discussed in light of this.

Blue light

Prior to utilizing blue light, it is essential that it be mixed with other types of bulbs. However, some plant species may be stunted in growth due to this color’s effect on leaf thickness and color, energy acceptance, and chlorophyll concentration. Growth and maturity rates can be boosted by a low level of blue light intensity.

Red light

Greenhouse plant growth is also aided by the usage of red light. You should use this spectrum in conjunction with blue if you truly desire well-developed plants. A wavelength that influences germination, flowering and leaf expansion is why this wavelength is important.

Green light

Green is the least efficient color in the spectrum, thus gardeners tend to disregard it. However, according to researchers at Michigan State University, it is still useful in the photosynthesis and structure of plants. For greenhouses with heavy top canopies, a green light is also helpful in order to ensure that the lower canopy leaves are still exposed to light.

What Is DLI?

When trying to find out what color grow lights should be, you may come across the phrase DLI (dynamic light index). When it comes to photosynthesis, this word offers you an indication of how much light the plant will have at its disposal. Photosynthesis is the process by which plants obtain energy from the sun.

Increasing the DLI of grow lights in greenhouses aids in the production of high-quality plants. It is the plants’ productivity that will determine the rate of growth. It’s important to keep in mind how far apart your plants should be from your light, as well.

Keep in mind that you may utilize fluorescent, LED, or high-intensity discharge lights depending on the type of greenhouse you run. LED lights should be kept at least 30 inches away from your plants if you’re utilizing them. High-intensity discharge lights, on the other hand, can be placed up to eight feet above the plants with only a six-inch clearance over the foliage.

Is Light Intensity Important For Growing Plants In A Greenhouse?

Realizing the significance of light intensity in the greenhouse is the next logical step after becoming familiar with the color spectra. Photosynthesis occurs at a faster rate when the light intensity is higher. Grow lights are essential because greenhouse glazing reduces the amount of light that can be used for photosynthesis.

Color Light For Your Plants

It’s important to remember as a gardener that plants do well in a wide range of light colors. What matters most is how much or how intense each color is, rather than what color of light is being used to grow your plants.

Along with other factors, like as temperature, a greenhouse gardener is responsible for ensuring and monitoring the right color of light.

It’s advantageous to have control over your greenhouse’s atmosphere since you can design one that’s suited for your plants regardless of where you are or what kind of weather you’re having.

Best Color Light For Growing Your Plants

In a greenhouse, what wavelength of light is most beneficial to plant growth? In a greenhouse, many gardeners employ green, yellow, and orange lights, believing that these colors are similar to the spectrum of light given out by the sun.

In a greenhouse, we’re attempting to duplicate the ideal circumstances that your plants need to thrive.

Recent research shows that your plants’ photosynthetic activity occurs at frequencies in the blue and red ranges of the electromagnetic spectrum.

It’s best to use red and blue lights, which absorb maximum chlorophyll, which is helpful to plants, if you want a beautiful and healthy harvest.

When it comes to cultivating your blooming plants in a greenhouse, there are many different types of lighting and colors you can utilize.

A broad spectrum LED grow light is the greatest option for growing your plants in a greenhouse, even though blue and red are the optimum colors to utilize.

LED compared to fluorescent

In a greenhouse, what wavelength of light is most beneficial to plant growth? The blue light from a fluorescent bulb will help you grow larger plants.

As a bonus for seeding your plants, fluorescent lamps don’t produce a lot of heat, which is critical when caring for your plants in the greenhouse.

Fluorescent lamps are available in either warm white or cool white to assure the growth of your plant (with more blue color in it).

Although fluorescent bulbs utilise wavelengths that LED lights do not, LED lights are more cost-effective and long-lasting.

In addition, LED lights make it easy for owners, farmers, and gardeners to select the true color spectrum, which fluorescent bulbs cannot supply.

Keeping this in mind, the following information will explain how each hue affects the growth of your plants in your greenhouse.

Blue color

When using blue light, remember to blend it with different spectra of bulbs to ensure the best results.

The color, energy acceptance, and leaf thickness of your plants can all be influenced by blue light, which might cause growth stunting in some plants.

Blue light can help your plants mature and grow faster, as well as reduce the amount of water they use.

Red color

Red light has a similar effect on plant growth in a greenhouse. In order to have healthy and well-developed plants, it’s best to use the red color spectrum in combination with blue.

The color red is beneficial to your plant’s growth since it plays a major part in seed germination, the expansion of leaves and stems, and in the flowering stages.

Green color

Because of its low efficiency, gardeners prefer to overlook green as a color for their lighting because it is one of the most beautiful.

Michigan State University researchers say that the hue green is still useful in the photosynthesis and structure of greenhouse-grown plants.

By utilizing the green light, even large, overhanging greenhouse canopies can receive enough green light to support photosynthesis in the lowest portions of their leaves.

Light Intensity Vs. Color Of Light

When growing plants in your greenhouse, the strength of light is more significant than the color of light. In addition to studying the color spectra, it is essential to understand the impact of light intensity while growing healthy plants in a greenhouse.

Your plants’ photosynthetic rate will increase if the light intensity is increased.

Keep in mind that greenhouse glazing reduces the amount of light accessible to your plants for photosynthesis, thus grow lights are essential.

What light is needed for plant growth?

A divide between cool and warm light, mimicking the spectrum of natural sunlight, is the ideal light balance for plants. You will require a lamp with a certain spectrum range depending on the type of plant and the stage of cultivation. When a light source emits a spectrum, it emits light in a variety of wavelengths. Different plants can benefit from different colors of light. Take a peek at the box the next time you buy bulbs. In most cases, you will notice a figure like 2700K or 3000K, which indicates the light spectrum’s temperature.

For the most part, plants require more blue light when they are growing and developing, and when they are flowering and producing, they require red and orange light. In this section, we’ll examine various kinds of greenhouse lighting and the colors they emit.

The types of greenhouse lights

In greenhouses, you’ll come across four basic types of lights. Some of the following terms and acronyms are probably familiar to you:

  • Incandescent
  • Fluorescent lighting (HIF)
  • Discharge at high intensity (HID)
  • A diode that emits light (LED)


These types of lights aren’t common anymore, but they were formerly common in homes around the country. Because these lights are inefficient, governments around the world have begun to phase them out. The greenhouse isn’t the best place for them. The filament within an incandescent bulb is heated to produce visible light. Place them away from the vegetation because of the heat they produce.

As a general rule of thumb, they are the cheapest option (assuming you can locate them) and while they do provide an excellent source of red wavelengths, there are far better solutions for your greenhouse that aren’t prohibitively expensive.

High-intensity fluorescent

High-intensity fluorescent (HIF) bulbs are substantially more efficient than incandescent lights because they transform electricity into light without wasting heat. These bulbs emit a lot of blue light and very little red light, but they also provide a full spectrum of white light. If you decide to take this route, look for a T5 fluorescent bulb, which produces three times more light in both the blue and warm spectrums than other bulbs.

As a general rule, HIF bulbs are a good choice for greenhouses that don’t get as much sun exposure as they could. Propagating plants and growing plants in a large space could save you money because to the high energy efficiency of these bulbs.

Light-emitting diodes

LED lights, which are more expensive but consume half the electricity and last five times as long as fluorescent bulbs, are the most energy-efficient option. In addition to having a higher light output, they also create a wider range of visible light. Because they are so little in comparison to other bulbs, they are also quite simple to set up.

Light emitting diodes (LED) are ideal for greenhouses because they produce the most photosynthesis-inducing blue and red light. LED bulbs can be employed at any stage of a plant’s development.

High-intensity discharge

High-intensity discharge (HID) bulbs are the only form of greenhouse light we suggest. Many farmers utilize HID lights in their own greenhouses because they are effective at creating light and boosting light intensity. It is possible to employ high-pressure sodium bulbs to encourage growth and blooming as well as metal halide lamps to assist vegetative growth, however these two forms of HIDS are not interchangeable.

HID lights, on the other hand, have two significant drawbacks. If you have a small greenhouse, you may want to avoid using fluorescent bulbs because they require heavy ballasts that must be purchased individually, and they take up a lot of room, making them less practical than LED bulbs. HID lights generate a lot of heat and must be kept at least 30 to 36 inches away from your plants to avoid overheating. Even if you have plenty of room, this is not the best option.

The right light is essential for the plant

What effect does the color of light have on plant growth?

The usage of blue light is recommended for plants that are only seeds and are just beginning to sprout.

Chlorophyll production is boosted by blue light at the beginning of a plant’s life cycle.

Blue light is essential for the growth of some seedlings.

When the plants are established and starting to flower, red and blue light are critical.

Using this method, they are able to grow more leaves and crops.

At any moment in a plant’s life, violet light can be employed to enhance the plant’s color and flavor.

Understanding visible light and how it relates to plant growth

Only a small portion of electromagnetic radiation is visible to the human eye; the rest is invisible to the naked eye.

Light, which is electromagnetic energy, can take a multitude of forms.

All of these include: visible light, infrared light and radio waves as well as gamma rays, x-rays, microwaves and radio waves

Even though some types and hues of light are advantageous to plant growth, other forms of light can be harmful to plant growth.

Visible light is merely a small portion of the full electromagnetic spectrum shown in this graphic:

Is there a reason why plants require it?


Photosynthesis is the process through which plants make their own food.

To produce food, chlorophyll–the green pigment found in plant leaves and stems–uses the energy of visible light to convert carbon dioxide into glucose.

As a result, plant growth is aided by the utilization of visible light.

However, can we alter or boost the amount of light we provide our plants in order to speed up or improve their health?

Yes, in a nutshell.

Another thing to know is that we have a full article devoted to the subject of whether plants grow better under natural or artificial light sources.

Quick science lesson on photosynthesis

We’ve talked about the effects of different colors on plants, but I think it’s equally important to know the science behind why those effects occur.

Consideration should be given to photosynthesis, chlorophyll, and wavelengths when analyzing the effects of various colored lights on plant growth.

Light, water, and carbon dioxide are used by plants to produce glucose and oxygen through photosynthesis.

Glucose is a form of sugar that plants eat to keep them healthy and vibrant.

Oxygen is one of the byproducts of photosynthesis.

Chlorophyll is essential for photosynthesis to occur.

The pigment chlorophyll is responsible for plants’ green color and for their ability to convert light energy into nourishment.

Due to chlorophyll being green, plants thrive best when exposed to hues on the other side of the spectrum from green: red and blue.

Light is a form of energy, and its wavelength is determined by the color.

Due to its shorter wavelength and hence higher intensity, ultraviolet radiation is the most common type of electromagnetic radiation.

Violet, blue, green, yellow, and finally red are the next colors in decreasing order of wavelength, with red having the longest wavelength and being the least energetic.

Choosing the right light for plant growth is critical here.

Because UV radiation is so powerful, it is really detrimental to plants because of its intensity.

As a result, the usage of red light alone is less beneficial to plant growth.

Understanding how light affects plants is critical.

Photosynthesis, the process by which plants convert light energy into food, would be impossible if plants did not receive sufficient light energy.

What the heck is DLI, and why should you care?

DLI is frequently used by commercial greenhouse growers and horticulturists as a baseline for determining the health of their plants.

Do you know what DLI stands for?

For the purposes of calculating a plant’s photosynthetic capacity, DLI (the daily light integral) is a useful metric.

Plants don’t use all of the light they get for photosynthesis.

Several colors and wavelengths of light are utilised by plants in different ways, and some wavelengths can’t truly be utilized at all.

DLI measures the amount of visible light, or light in the 400-700 nm range, that is available to the plant for photosynthesis.

The more DLI your plants have, the more they are able to photosynthesise and thrive.

The glazing of greenhouses reduces the amount of light that plants can receive.

Researchers from Purdue University and Michigan State University discovered that the only method to improve DLI in a greenhouse and generate high-quality plants was through the use of grow lights, or supplemental lighting (original article here).

You should monitor DLI and how much daily light each sort of plant you’re cultivating needs if you want to make sure your plants grow to their full potential.

For maximum plant health and growth, red and blue are the most critical hues in the visible spectrum.

UV light is damaging to plants, but green and yellow light have minor effects on them.

The following table provides information on the effects of each light color on plant health and growth.

Ultraviolet Light

UV light, often known as ultraviolet light, is widely believed to be detrimental to humans.

Humans can get burnt and suffer other severe effects if they are exposed to too much UV light.

High-intensity or long-term exposure to UV light harms plant growth in the same way as prolonged human exposure to UV light does.

The less UV radiation your plants are exposed to, the better they will grow.

Violet Light

A plant’s growth is aided by exposure to violet light.

A plant’s ability to make antioxidants is improved when it is exposed to violet light.

For this reason, violet light is a useful tool for increasing plant growth and preventing harm.

Blue Light

In the early phases of growth, blue light is beneficial to plants.

The green pigment chlorophyll, which traps light energy and is essential to photosynthesis, is produced by plants with the help of blue light.

The energy in blue light is therefore more readily absorbed by plants and utilized during photosynthesis.

As a result, blue light speeds up the maturation process for plants.

For seedlings and young plants, blue light is particularly vital.

Blue light can help seeds germinate and guarantee that roots, stems, and leaves grow to their full potential.

Green Light

Green light, on the other hand, is reflected by plants.

It’s for this reason why plants often have green foliage.

Chlorophyll production is boosted by using mostly green light, which makes the plants appear greener.

It is true that green light isn’t as essential to plant growth and health as red or violet light, but in commercial greenhouses where customers are examining and picking plants, green light is important.

Yellow Light

In terms of promoting plant development and health, yellow light is similar to green light in this regard.

There are some studies that demonstrate that removing yellow light from greenhouses may create healthier plants than growing the identical plants outside in full-spectrum sunlight, even though yellow light does not directly aid generate chlorophyll.

Red Light

Light emitting from red bulbs is less powerful than light emitting from other hues.

Red wavelengths, on the other hand, are extremely beneficial to mature plants when used in conjunction with blue light.

Red light encourages flowering.

The number of leaves that a plant produces is considerably boosted when red and blue light are used together.

If plants are cultivated under exclusively red light, they will appear elongated and thin, according to a study by the Michigan State University floriculture extension team.

Adding 10% to 20% blue light improved the health and beauty of the plants.

For example, there’s far red light, which has wavelengths lower than regular red light—similar to near-infrared.

Using far-red light encourages plants to generate more food.

This is accomplished by speeding up a plant’s nighttime metabolic processes with the use of far-red light.

The blooms ripen in the darkness of the night.

Red light aids in the growth of your plants by speeding up the nocturnal process.

The perfect lighting for your greenhouse – Greenhouse Hunt

Choosing the right light

Plants require a variety of colors in their lighting, despite the appeal of a light that focuses just on one color.

Plants thrive best when exposed to a variety of light sources.

Having a higher concentration of blue and red light rather than yellow and green light will result in improved plant function.

Additionally, the intensity and duration of the light should be taken into account when selecting a light.

The amount of photosynthesis that a plant undergoes rises with the intensity of the light it is receiving.

When it comes to outside lighting, the sun dictates how long daylight lasts. However, in a greenhouse, the lights should be kept on for 12 to 14 hours each day to get the greatest results.

I’ve put together a separate article with updated information and detailed recommendations.

Finally, here are some of the most common light sources:

  • Due of its higher power consumption and heat output, high intensity discharge lamps are used primarily by large-scale growing activities.
  • Fluorescent lights last longer and emit more blue light than incandescent bulbs. Leafy plants like herbs and lettuces can benefit from the limited color spectrum provided by these bulbs. They’re popular because of their long lifespan, low heat output, and low energy consumption.
  • Unlike incandescent bulbs, LED lights may emit either red or blue light. They are becoming increasingly popular among hobbyists, however they should not be utilized in large-scale greenhouses because of their low intensity.
  • The use of incandescent bulbs in a greenhouse is not recommended. These are more commonly employed for their visual appeal than their use. Despite the fact that they are less expensive than other types of lights, they do not give the necessary intensity for plant growth.

How Far Should Grow Lights Be From Plants?

Lighting type has an impact on how far a light source must travel to reach a plant:

  • 5 to 8 feet above the plants: high-intensity discharge lighting
  • 4 to 6 inches above the plant is the ideal height for fluorescent lights
  • From 14 to 30 inches above the plants: LED lights

Using light boxes, chains, and light bulbs, you can construct your own grow light.

Adjusting the distance between the light and plant is done via chains.

Depending on the size of your plants, you may need to change the distance between the light and the plant.

To learn more about the ideal distance between LED grow lights and plants, read the rest of this article.

Related questions

Does leaf color affect photosynthesis?

Because chlorophyll content in green leaves is higher than in other leaf hues, they do, in fact, have a higher rate of photosynthesis. In comparison to green-leaved plants, those that have a predominance of reddish leaves are less productive, growing slower and producing less biomass.

Does light intensity affect plant growth?

Yes, the rate of photosynthesis can be accelerated by increasing the intensity of the light. Due to the increased intensity of light, photosynthesis will proceed more quickly. To compensate for the loss of light that greenhouse glazing causes to plants, additional lighting should be used.

Do plants grow under white light?

It is natural for plants to have access to full-spectrum light, as the sun provides this light in the first place. The ideal light for plants is direct sunlight, although white light can be used in a greenhouse as well; however, you may find that you need to experiment with several light sources to find the one that works best for the particular plants you’re trying to grow.

Does green light affect plant growth?

In terms of plant development, green light is the least effective. In order to know that plants don’t absorb green light, you can see that they seem green because green light is reflected from them rather than absorbed by them. For photosynthesis, green light is still important but not nearly as crucial to the process.


It can be difficult to maintain optimal greenhouse conditions. Do you know what color of light is ideal for growing plants in a greenhouse??? Because blue and red are the most important colors for plant growth, the obvious response is a combination of the two.

According to research, these hues closely resemble the spectrum used by plants. A full-spectrum LED grow light will be the most useful for your plants, even though these are the greatest hues. In order to ensure the health of your plants, discover how much of each hue your plants will need.