With the continuous development and progress of LED market technology, Grow lights are currently another important market development in the field of LED lighting industry. Since 2013, the output value of indoor LED grow lights has begun to show a high growth trend. At present, the US, Canada, Sweden, the United Kingdom, and Israel have been in the forefront of the development of plant factories. Southeast Asian countries South Korea, Singapore and China are also developing rapidly.

More and more indoor growers are buying grow lights to increase the harvest of crops and hemp.
However, when buying LED plant growth lights, you should know that the most important factor in plant production is the spectrum.

For the selection of the plant light spectrum, first you need to know what the plant is planted, because different plants have different requirements for color temperature. If you don’t get the correct light ratio, no matter how much you spend, the plant will not grow good.

If you want to make your own plants grow better, you need to consider the latest technology products on the market—– LED grow light, because they are more energy-saving and environmentally friendly. It also saves you more money. For most growers, how to choose the right type of lamp is not easy. At present, there are various plant light products in the price range on the market. The styles and prices of each supplier are different, which brings some confusion to many buyers. Now I am happy to share with you professional information how to choose the right spectrum.

At present, there are many plant production needs on the market, such as hemp, vegetables, tomatoes, succulents, hydroponic seedlings, etc. How to choose the spectrum for these different plants.

What is the color spectrum?

Plants are genetically programmed to use sunlight to grow. We think sunlight is white or yellow-white. This light looks white because it contains all the colors of the rainbow, and when these colors are mixed together, they look white.
The color spectrum is a graphical display of each color in the light.

The color spectrum is a graphical display of each color in light. Scientists use wavelength numbers to represent colors instead of color names, which is a more accurate color measurement method. So the wavelength of red may be 630nm or 660nm. These two colors seem to us to be red, but in fact they are a little different colors.

For LED Growth lights that use fluorescent bulbs, the color of the bulb is called cool white (more blue) or warm white (more red). This is useful for fluorescent lights, but this name does not work for LED lights. When it comes to LEDs, it is more accurate to speak with wavelength and display the actual color spectrum.

What colors do plants use?

The plants use light mostly for photosynthesis and this is done with specific chemicals in the leaves.

Color absorbed by pure chlorophyll a and b
Color absorbed by pure chlorophyll a and b
Plants mainly use light for photosynthesis, which is done through specific chemicals in the leaves. More important chemicals include chlorophyll A and B. In the absorption spectrum (measuring how much light is absorbed), you can clearly see the peaks in the blue and red regions, which means that these colors are used for photosynthesis.

Almost there are no light is absorbed in the green spectral range.

This leads to the wrong conclusion that plants only need blue and red light.

Blue and Red Color

The light wavelength absorbed by the plant is used for the photosynthesis of the lamp.
The plant are growing well under only blue and red color is actually a myth. The above chromatogram is for the purified chlorophyll in the test tube, it does not show what is happening in plant leaves.

Photosynthesis is more complicate and involves other chemicals such as carotene and lutein. The color spectrum of light absorbed by the entire leaf shows that plants actually use a wider range of wavelengths, including green color.

Blue and red are indeed important and represent most of the light used by plants, but other colors, including green and yellow, are also used for photosynthesis.

Different colors have different effects

Red color (630-660 nm) is important for stem growth and leaf expansion. This wavelength also regulates the stages of flowering, dormancy and seed germination.

Blue color (400 -520 nm) needs to be carefully mixed with light in other spectra, because excessive exposure to light of this wavelength may hinder

the growth of certain plant species. Light in the blue range also affects the chlorophyll content present in the plant and the thickness of the leaves.

Green color (500-600 nm) can penetrate the thick top canopy to support the leaves in the lower canopy.

Far-red color (720 – 740 nm) can also pass through the dense upper canopy to support the growth of leaves located in the lower part of the plant. In addition, exposure to infrared light can reduce the time it takes for plants to bloom. Another benefit of far-red light is that plants exposed to this wavelength tend to produce larger leaves than those that are not exposed to the spectrum.

Best color spectrum depends on the plants to grow

As plants grow from seedlings to adults, then bloom and bear fruit throughout the maturity cycle, they use different color spectrum, so the ideal LED light is different at each growth stage.

The best color spectrum also depends on the type of plant you are trying to grow.

This can become very complicated and it is only really important for commercial growers who want to maximize results.

As a general rule, plants perform best at all wavelengths of light, but they do not need to have the same amount of light at each wavelength.

What is PPFD?

The actual measurement of light quantity is PPFD (photosynthetic photon flux density), sometimes abbreviated as PFD. Compared with luminous, PPFD is a better way to measure the amount of LED plant growth light.
Comparing PPFD values is the next best thing. The higher PPFD will provide more light for plant growth.

Our led grow lights, spectrum test report: PPF 2.8umol/J.

For different plants, we can provide different chromatograms

According to the our customer’s feedback that the cannabis planting are popular by indoor growers, and also for vegetable and succulents are hot-selling markets.

Cannabis seeds can germinate at a low temperature of 1-4.5°C, but to emerge quickly and neatly, the soil temperature needs to be above 8-10°C.

The seeds germinate quickly at the optimum temperature, but the seedlings grow too long.

According to experiments conducted by the Economic Crop Research, hemp seeds will emerge in 8-12 days when the temperature is 8-10℃, 7-10 days when the temperature is 11-16℃, 6-7 days when the temperature is 19-20℃, and 23-26℃. Seedlings emerge within 3-4 days.

The emergence period of hemp seeds after sowing is closely related to the temperature.

Under suitable conditions in the field, seedlings can emerge 3-10 days after sowing. The number of days from emergence to seed maturity call growth days. The growth days of hemp in my country are 80-100 days for early-maturing species, 101-150 days for middle-maturing species, and 151-210 days for late-maturing species.

Hemp and vegetables: white light and red light, hemp has high lumen red light, vegetables have low lumen red light, and the ratio of white to red light is 23:1.

Tomato is a perennial herb in the tropics, but it is cultivate as one year in temperate frost areas. Its growth and development process has certain stages and periodicities. It  divide into four stages: germination, seedling, flowering and fruiting. different periods.

Germination period: from seeding to the appearance of the first true leaf (broken heart). Under normal temperature conditions, this period is 7 to 9 days. Under normal temperature, it usually takes 10-14 days from seeding to heart breakage of true leaves.

Seedling stage: refers to the emergence of the first true leaf to the budding of the first inflorescence. The suitable day temperature during this period is 25～28℃, and the night temperature is 13～17℃. This stage is a transitional period from tomato’s main vegetative growth to the same development of reproductive growth and vegetative growth, which is directly related to the formation of product organs and yield;

Flowering period: The flowering period is from the present flower bud to the first inflorescence fruit. It takes about 15-30 days. In addition to the differentiation and development of flower buds and leaf buds, the plants during this period are also very vigorous in vegetative growth. In appearance, the plant height increases and the leaves continue to grow.

Fruiting period: from the first inflorescence fruiting to the end of harvesting (pulling seedlings). During this period, fruit and seedlings grow at the same time. Solving the contradiction between vegetative growth and reproductive growth is the key task in this period.

Tomatoes: red light and blue light, the ratio of red to blue is 7:1, the installation height is 18 inches

Succulents: there are main need red lights

Seedlings: only pure white light is require, and the height of the growth lamp is about 24 inches