The Role of Red & Far Red Light for Plant Growth
Among the different growth light spectrums, red and far red light might be something you’ve heard about but are not familiar with. Is red light important in the stages of plant growth? If so, what exactly does red light do for plants? In this article, we’ll walk you through the role of red and far red light and explore the magic of red grow lights.
Red Light for Plants
Red light, generally ranging from 620 to 750 nanometers, is a key element for plant photosynthesis. In this wavelength, red light is absorbed by chlorophyll, the green pigment in plant cells, enabling plants to convert light energy into chemical energy to produce crops.
Beyond its role in photosynthesis, red light also regulates plant development through a light-sensitive pigment called phytochrome. When exposed to red light, phytochrome converts from its inactive form (Pr) to its active form (Pfr), which serves as an important signal in controlling flowering and fruiting.
In long-day plants, high levels of Pfr activate genes that promote flowering, whereas in short-day plants, Pfr prevents flowering until environmental conditions are suitable. By affecting the timing of flowering, red light can help growers achieve more predictable and concentrated blooms.
Red light can also enhance hormonal signaling pathways, including auxin and gibberellin. Auxin helps flowers develop more fully and completely, while gibberellin allows fruit cells to swell fully and grow more symmetrically. Under the synergistic effect of these hormones, the number of flowers increases, and the fruit set rate improves.
Far Red Light for Plants
Far-red light, with wavelengths ranging from 700 to 750 nanometers, lies at the edge of the visible spectrum and is nearly invisible to the human eye. Far-red light was long believed to have little to no benefit for plants.
However, recent findings have revealed that it can significantly influence plant development. For example, research by Dr. Shuyang Zhen and Dr. Bruce Bugbee (2020) has demonstrated that far-red light can improve photosynthetic rates and increase plant biomass.
The study found that supplementing shorter-wavelength light with far-red photons boosted canopy photosynthesis, with species-specific effects: red lettuce, corn, soybeans, and tomatoes experienced roughly 20–30% increases in photosynthetic rate, while kale showed the largest gain, reaching 59%.
Additionally, Dr. Shuyang Zhen and Dr. Bruce Bugbee observed that adding far-red light to a standard white light spectrum increased the biomass of indoor lettuce crops by 29–31%, highlighting its potential to enhance indoor plant production.
Science behind Far Red Light for Plants
Far-red light, like red light, is detected by plant phytochromes, but it uniquely converts the active form of phytochrome (Pfr) back into its inactive form (Pr). This conversion enables plants to sense changes in light quality and adjust their growth accordingly.
For instance, when plants receive far-red light instead of red light, they may interpret it as shade from nearby taller plants. In response, they often grow taller or orient themselves toward the light source. This phenomenon helps plants optimize the light required for photosynthesis.
Far-red light also influences the balance between vegetative growth and flowering. When used alongside red light, it helps maintain an optimal phytochrome balance, allowing growers to fine-tune flowering and overall development. This can improve crop quality and control growth cycles in a targeted way.
Utilizing Red Light in Indoor Plant Growth
If you're looking to improve plant health and yield by optimizing red light wavelengths, consider the newly upgraded Mars Hydro FC-E Series LED grow lights. The new FC-E series features a comprehensive upgrade with significantly improved performance, as detailed below:
Upgraded OSRAM Red LEDs
The new FC-E series features the renowned OSRAM CSSRM6.24 red LEDs, which deliver industry-leading red light performance. These LEDs enhance the critical red spectrum that drives flowering and fruiting, resulting in faster, more abundant blooms, higher and more consistent fruit yields, and improved fruit quality and uniformity.
Improved Light Efficiency
The FC-E series also uses high-efficiency Bridgelux diodes with a PPE of 2.8 μmol/J. Coupled with a high-density, scientifically arranged chip layout, this ensures uniform PPFD and even canopy coverage. This promotes faster growth, stronger stems, and a more uniform canopy structure.
Optimized Spectral Ratio
The full-spectrum design combines optimized blue, white, and enhanced red wavelengths, supporting plants at every stage, from vegetative growth to full bloom. The precisely tuned red-to-blue ratio promotes flowering without excessive vegetative growth, allowing growers to maximize yield and crop quality.
Higher Performance at Same Price
Overall, the new FC-E series delivers a comprehensive performance upgrade while maintaining the same price as the previous model. With an enhanced red light configuration, it provides stronger flowering performance and improved growing results. Users can now enjoy a higher-output grow light at the original price.
In addition, the upgraded structure features detachable light bars or a triple-folding design, making installation more convenient. Warranty coverage, after-sales support, and compatibility remain unchanged, allowing users to upgrade or replace their existing model with confidence.
Supplemental Red Light
If you want to supplement your plant's light intake with extra red light, the Mars Hydro ADlite Deep Red + Blue Supplemental LED Grow Light is an excellent choice. The kit includes two light strips (15W each), each emitting a specific spectrum containing 660nm red light and 440nm blue light.
Mars Hydro red supplemental lights promote larger, fuller flowers and fruits, leading to improved yield. The deep red spectrum also supports better flavor development and overall crop quality. By adding supplemental light, growers can fine-tune the spectrum to meet the specific needs of their plants.
Answered: Is Red Light Good for Plants
Yes, red light helps plant photosynthesis and flowering regulation, as long as you use it properly. By incorporating red light into your grow tents, grow rooms, greenhouses, etc., you stand a chance to enhance plant health, promote strong blooms, and boost fruit production.
For best indoor gardening results, combining full-spectrum lighting with supplemental lighting is recommended, such as the Mars Hydro FC-E series paired with Deep Red + Blue Supplemental Light. This setup provides a balanced spectrum while boosting key red and blue lights, supporting all growth stages, and promoting a thriving garden.
