What is Full Spectrum Light Vs Red and Blue Grow Lights

Grow lights can replace sunlight to promote plant growth,which can not only promote the growth of seedlings, but also promote flowering and fruiting, increase production and harvest in advance.

There are many types of grow lights, such as:  full spectrum grow light and red and blue light grow light. So,what is the full spectrum light,Is better than the red and blue grow light?Let’s explore the detail in this guide.

The full-spectrum grow light is a lighting source designed like the solar spectrum to promote plant growth. A reasonable distribution ratio from the blue light to the red light in the spectrum, and the light wavelength curve imitates the shape of the sun’s spectrum,such as:the light color as bright daylight color at about 10 o’clock in the morning, strong color rendering, small color temperature drift, high luminous efficiency and large luminous flux.

Illuminance and Light compensation point:

The light compensation point is the illuminance when the photosynthetic and respiration of the plant are equal.

Above the light compensation point,it can accumulate organic matter when photosynthesis of plants exceeds respiration. Below the light compensation point, the respiration of plants exceeds photosynthesis,instead of accumulating organic matter, the stored organic matter is consumed.

When the temperature rises, the respiration increases and the light compensation point rises.If below the light compensation point for a long time, the plant will gradually wither and cause death. Therefore, when plants in a greenhouse, It should prevent high temperature when the light is insufficient to decrease the light compensation point.

The light compensation point of a group plant is also higher than that of a single leaf. Because there are many leaves in the group, they shade each other. When the light is weak, the upper leaves can still do photosynthesis, but the lower leaves have strong respiration and weak photosynthesis, so the whole light compensation point rises.

spectrum comparison

From above the spectrum,we know that the incandescent light used in the past has an uneven spectrum, but the spectrum is relatively comprehensive. Under a certain condition, it still is beneficial for promoting the growth of plants, but the low light efficiency,the high energy consumption and short lifespan. It is a large curve changing and uneven spectral distribution for HPS light and energy-saving light.There are some advantages in the ratio of red and blue for LED grow lights, but the spectrum is less than sunlight,relative high cost and low brightness. Full-spectrum grow light that the distribution simulates the solar spectrum, is an ideal grow light source for indoor plants in greenhouses, agricultural research institutes and agricultural ecological gardens.

What is a full spectrum grow light?

Full-spectrum light is designed by imitating the sun’s spectrum,the light is similar to sunlight, which can be used to illuminate plants and promote their growth.

Is the full-spectrum light harmful to body?

The full-spectrum light is just like the sunlight, which is not harmful to the body. If the full-spectrum light excessively illuminate plants for a long time , it will also be negative on plant growth and cause a waste of energy.

Full-spectrum grow light layout

35W full spectrum grow light: the lighting radius is best around 4-5 meters, the installation height is best at 2-2.5 meters, and the interval is 4-5 meters.

70W full spectrum grow light: the lighting radius is best around 5-6 meters, the installation height is best at 2.5-3 meters, and the interval is 5-6 meters.

150W full spectrum grow light: the lighting radius is best around 10 meters, the installation height is best at 5-7 meters, and the interval is 10-12 meters.

250W full spectrum grow light: the lighting radius is best around 15-20 meters, the installation height is best at 8-12meters, and the interval is 15-20 meters.

Full spectrum plant light wavelength range:

Full spectrum plant light contains light with a wavelength of 400-420nm to help form anthocyanins and resist the elongation of branches and leaves.

Light with a wavelength of 450-460nm, which can thicken stems and leaves, promote plant development and regulate stomata opening.

Light with the wavelength of 550nm to promotes the growth of oxygen and help tissues to  accumulate nutrients better.

Light with the wavelength of 580nm to promote the growth of roots and early germination.

Light with a wavelength of 650~660nm to promote the overall growth of the plant, especially in the flowering and fruiting period, increasing the growth speed (20 days earlier flowering, 30 days earlier harvest), also increases the number of fruits by 25% to 35%, and reduces deformed rate of fruits.

Light with a wavelength of 720 ~ 1000nm to stimulate cell elongation and affects flowering and seed germination even if  low absorption rate,

In addition, it also contains a small amount of ultraviolet light, which can effectively prevent pests and diseases,go here to know more what color light is better plant growth.

Full Spectrum Light Vs Red and Blue Grow Lights

After studying the absorption of sunlight by plant growth, It is found that the largest absorption light by plants is red and blue light in sunlight . Red light is beneficial to promote plant flowering and fruit, and blue light is good to promote plant growth, stems and leaves. So, people developed plant lights with red and blue spectrum. This kind of light has good impact on the growth of plants. Moreover, the ratio of red to blue light can be customized according to requirements to promote plant growth better.

There are only two spectra of red and blue light in these grow lights, while full-spectrum grow lights simulate sunlight,its spectrum is the same as sunlight, and the light emitted is white light.

The difference between the red and blue grow light and the full spectrum:

The red and blue grow light is made of red light + blue light based on a certain ratio of the number of lamp beads,which can be a single lamp bead or an integrated one. The full spectrum light is made up of fluorescent powders with different ratios of blue chips to contain multiple wavelengths of lamp beads, which are basically single.

The full spectrum is an upgraded version of the red and blue light,which is suitable for most plants.

Both grow lights are beneficial for promoting plant growth, but it is important to choose right one according to actual requirement.

For flowering and fruiting crops and plants need to be colored, it is better to use red and blue grow lights, which can color, promote flowering and fruiting, and increase yield. For leafy crops,we can use full-spectrum grow lights better. If you grow plants at home, it is better to choose a full-spectrum plant light, because the light of the red and blue plant light is pink, if people stay in this environment for a long time, It will feel unwell.

The difference between full spectrum and red and light for Succulents

Rend and Blue light Pros:

Red and blue grow lights are relatively mature in technology. The wavelength of blue light is about 450-470NM, and the wavelength of red light is about 630-660NM. These two wavelengths are the most significant for plant growth.  The rate of light utilization is extremely high, and it will not emit wavelengths that plants do not absorb, so as to achieve the energy saving.


Some people will not like the light color,and lack of some color light.

Full spectrum light

Full-spectrum grow lights is a new upgraded in technology, and may be not stable. Its wavelength is range from 400-800nm, the color is white that more comfortable,which is beneficial to plant growth.

but the rate of light utilization is not high than that of red and blue because of some wavelengths that plants do not absorb, which generates unnecessary heat and consumes more electricity.

Both types of grow light are beneficial to Succulents growth. In general, the red and blue lights have advantages in efficiency, price, and power consumption. The advantage of the full spectrum is in the visual effect.

Wrapping up

Through the above introduction, we already know what is a full spectrum grow light and the difference between full spectrum and the red and blue plant grow light. As for which light is better, it needs to be determined according to the type of plant you growing.

The full-spectrum grow light is an upgrade of the red and blue grow light. The price of full spectrum is higher than that of the red and blue light, which is suitable for large parts of plants. However, the red light plant light is more efficient for some plants and requires less energy consumption, but the color is not as comfortable as the full spectrum.