The pursuit of an adequate amount of sunlight during the cold, cloudy days has been the ultimate plight for growers. Sunlight has always been the sole source of light energy for plant cultivators for years until the technology introduced its fantastic alternative- “the grow light,” especially the ever-demanding LED lights.

However, many are confused about whether LED grow lights are better in performance and productivity than sunlight.

Well, it’s really a subject of interest for many growers.

If you're curious about “Can LED grow lights replace sunlight," we suggest you to read this guide. This will give you clarity about the tremendous benefits of LED over sunlight and how they’re a better alternative for plants.



The Concept of LED Grow Lights and The Importance of Sunlight for Plant Growth- The Comparison.

Since childhood, our science books have been telling us about sunlight being the primary requirement for plants to grow, but most of us are ignorant of the science behind it. The reason why sunlight is given this importance is that Sunlight contains a full spectrum of colors, including the red and blue wavelengths,  that are vital for plant photosynthesis and other physiological processes.


However, sunlight availability is vastly dictated by geographical and seasonal factors. In those areas with cold temperatures, their plants experienced a deadly state because of lack of light.


Even in the equatorial regions, where sunlight is abundant, the plants are exposed to this light source for only about 6-8 hours. And as you move up, the sunlight availability starts decreasing.


This marginal gap and inefficiency of sunlight gave birth to LED grow light, a relative newcomer to the grower's toolbox.


LEDs are known to provide favorable benefits to growers, including the flexibility to control the color spectrum for your plants around the clock. Also, cultivators are in charge of speeding up the illumination and turning it into the plant's best interest to optimize the plant growth cycle.


Not only are LEDs an effective choice for plants, but their ability to substantially reduce electricity costs and minimum heat generation has contributed to a broader adoption of LEDs.


However, the full-spectrum LED technology is a major hit these days. This technology contains a spectrum of light similar to that of Sunlight. These specialized lights are designed to offer a well-rounded spectrum that facilitates various stages of plant growth.  


All in all, Full spectrum LED grow lights offer extended periods of light and controlled climate conditions, giving Sunlight considerable competition.


The Science of Plant Growth

The healthier green leaves and the colorful flowers that you see blooming in your garden are a result of a plant's complex mechanism, highly regulated by various internal and external factors. The component that heavily contributes to plant growth and development is light.

Generally speaking, A plant’s life cycle is divided into four main stages—seeding, germination, growth, and harvest. Despite having a life cycle, plants also have light cycles, which are closely related to their growth stages.

During the entire growing journey, Sunlight lets the plant molecule chlorophyll turn this light into usable energy to fuel their leaves and facilitate cellular respiration- a process widely known as photosynthesis.

Plant photosynthesis only happens when there are special light conditions, such as a particular light intensity and color wavelength. If the process of photosynthesis ceased, there would soon be no growth for plants and, hence, no organic food for life.


Among the broad spectral distribution of sunlight, the colors in the PAR (photosynthetic active radiation) region of wavelengths (400nm-700nm)  trigger photosynthesis and continue to facilitate the plant growth journey. The blue light aids during the early vegetative phases, while the red light helps during the flowering and fruiting stage.


However, excessive plant exposure to  UV and IR radiation in sunlight sometimes becomes problematic and can lead to harmful consequences. Also, plants experience late growth when this sunlight becomes inadequate, disappears at night, or remains absent during winter.


To tackle all these concerns, artificial grow lights such as LEDs with precise wavelengths constitute a significant rescue. They're built to offer plants favorable light quality at each growth stage, along with higher energy efficiency and minimum heat emission. What a deal package for growers!


These light fixtures help growers fine-tune the light requirement as per the plant species and allow for a diverse range of crop cultivation in a controlled environment.


The Different Spectrum of Light Requirement for Plant Growth.

Before we begin elaborating on the light spectrum for plant growth, the first thing is to understand what the term “growth spectrum” really means. This refers to the specific band of electromagnetic wavelengths of light discharged by a light source that is capable of regulating and maintaining plant growth.


The light quality directly linked with plant growth parameters includes UV, blue, green, red, and far-red. These color ranges help to manage growth cycles and to produce specific substances that improve flavor and crop quality. By defining the differences between each light type and their contributions to plants, you'll be aware of which light spectrum works best for you.


UV Light:

UV, or Ultraviolet Light– the most heard term– is a part of the electromagnetic radiation found in natural sunlight. You get exposed to UV light every time you get out in the sun. Generally, UV is divided into three categories - UVA, UVB, and UVC but only UVA and UVB are plant lights. They help plants improve the overall potency and quality of their flower. UV grow light spectrum doesn’t aid plant growth directly but produces more secondary metabolites, say, flavonoids and terpenoids, which can improve plant flavor, aroma, and nutritional value. Meanwhile, it helps plants develop stronger stems and leaves.


The Blue Light:

Blue light, measuring a wavelength of 400-500nm, is a crucial player in the growth of plants. Although it's the least photosynthetically efficient in the PAR spectrum, it’s characterized by high energy, is essential for the structural formation of plants, and improves the quality of certain types of species. This light is mostly needed when plants are in the vegetative stage of development. This light facilitates the establishment of strong and healthy plant root systems, regulates stomata's opening and closing, and influences phototropism.


The Green Light:

The green light spectrum from 500-600nm doesn’t seem as helpful as the other wavelengths for plant growth, but it is valuable for photosynthesis, and research has found that green light can actually promote extension growth. It can relatively go deeper into the leaves, even the lower ones; thus, more leaves actively contribute to photosynthesis and aid productivity. The middle green part of the spectrum is known to regulate plant architecture, increase biomass accumulation, promote flowering in several plant species, as well as stimulate the production of secondary metabolites in plants, which are compounds that contribute to plant defense mechanisms.


The Red Light:

Red light, which falls in the range of approximately 600 to 700 nanometers, is another component that regulates plant growth. Red photons are the most photosynthetically efficient of all, and therefore, indoor cultivators prioritize red in the grow light spectrum. This light activates various genes to trigger flowering and stimulate the production of antioxidants and other protective compounds in plants, helping them to cope with environmental stresses such as high light and high temperature.


Far Red Light:

Rar-red radiation from 700-800nm helps promote extension growth and influences the size of the leaves, the length of stems, and ultimately the height of plants.

LED Grow Lights: An Overview

LED grow lights are energy-efficient lighting diodes purposely built for indoor greenhouse growers and cannabis cultivators. They use semiconductor materials to produce efficient lighting and serve as a sole light source for indoor plants or supplementary light fixtures in greenhouses.


The LED technology helps plants grow using full-spectrum lighting at a lower cost than traditional HPS lamps.


Due to their full light spectrum characteristics, low heat waste and maintenance, and extended lifespan, Many growers take advantage of LED grow lights to help scale crop production.


Given that a plant's physiology and morphology are strongly regulated by specific spectrums, LED grow light can significantly impact crop growth, yield, and quality at specific times in the growth cycle. With the ability to closely monitor productivity, energy output can be easily evaluated for scaling crop production.

Comparing The Light Spectrum Of LEDs With That Of Sunlight.

Sunlight and LED grow lights are realistically the most used light sources when growers are concerned about plant cultivation. When comparing the two, each constitutes their own set of benefits. However, their spectral distribution, known as the light spectrum, is the only thing that sets them apart.


Sunlight contains a diverse and broad spectrum of electromagnetic radiation, falling between Ultraviolent Radiation and Infrared wavelengths. This giant lighting star has been regulating most of the plant's physiological processes for years and is the only reason for providing organic food for survival.


However, Sunlight composition significantly varies according to atmospheric conditions, seasonal change, or geographical regions. The Earth's atmosphere scatters and filters the light, affecting the light intensity and distribution reaching the surface.


Artificial lights, such as LED lamps, fill this gap and attempt to mimic the essential characteristics of the sunlight spectrum. It takes mostly the PAR colors of the spectrum most favorable for plant growth; hence, it emits wavelengths tailored to different stages of plant growth.


 Advantages of Using LED Grow Lights Over Sunlight

Anywhere a conversation about indoor farming and planting pops up, there's no chance it would go without talking about the usefulness of LED grow lights.


That buzz is even evident from statistics revealing substantial growth with a recorded CAGR of 22.7% in the year 2023.


From a grower perspective, LEDs have indeed helped indoor farming to a greater extent and have cultivated to provide those fruits and vegetables all year round that were otherwise seasonal.


The most highlighted benefit of LEDs is their higher degree of customization. The presence of UV and IR rays in sunlight can sometimes be too hot for your plants, making them dry up easily and burn if left unattended. Obviously, with natural sunlight, you get what you get; there's no switch to increase or decrease the light intensity based on your plants' needs.


LED grow lights, however, offer control over light intensity; simply by using built-in reflectors or adjusting the height of the LED lights, you can fine-tune the light intensity to suit your plants' unique needs.


With the ability to provide plants with a targeted spectrum and enough supply of grow light 24/7, You become the one that tells the plants how to behave, resulting in multiple harvests in one season with auto-flowering plants.


Not only this, but LED can function at a very low temperature, meaning no harmful rays, unlike sunlight, where you get a lot of heat during extreme summer months, causing the plants to burn out faster. LEDs let you grow your plants for years without worrying about the replacement of the lights; hence, you ultimately save money in the end.  


With a lifespan of more than 50,000 hours, you can keep growing your herbs in a good amount of numbers with similar light chambers installed.

Limitations of LED Grow Lights

Despite being the technology of the future, LED grow light sources have their pitfalls, including the higher initial upfront cost and lack of certain wavelengths. However, these disadvantages are no longer viable as the brand Phlizon has manufactured the most efficient and affordable LED systems for cultivators.

The reason many new growers put LEDs on the downside is their high upfront costs. They're of the view that buying a similarly powered HID system is better than putting a good part of your money on LEDs. However, a little bit of calculation suggests that you actually save money in the long run when you go with highly efficient LEDs.


Another perceived downside of LEDs is their lack of particular wavelengths, unlike the broad and diverse spectrum provided by sunlight. Although LEDs deliver light in the PAR range, which is the most favorable thing for plants, the lack of UV and IR radiation can cause plants to have no secondary metabolites necessary for a plant's overall health and resilience to pests and diseases.


On the other hand, the absence of IR light fails to promote cell division and elongation, which is crucial for healthy plant growth.


This spectral limitation of some LED models is compensated by the Phlizon UV/IR series, which greatly replicates the natural cues that trigger plant physiological processes.


This simply means that by installing Phlizon grow lights, you’re at peace putting your plants under appropriate fixtures.


Practical Considerations

Plants respond differently to light exposures. Their light sensitivity is crucial for their survival, and any negligence would drastically reduce your gardening efforts. Hence, a few of the practical tips can be a game-changer for you. So consider this part very carefully.

Choosing the Right LED Grow Lights.

Employing the right LED grow lights in your indoor setup requires thorough learning and research. Just buying a good set of LEDs won't do all your job. In fact, growers who want to maximize their yield output with LEDs need to intelligently play with factors such as light intensity, duration, color spectrum, and coverage area.


Color spectrum is the most critical aspect of light optimization. Mostly, during the plant's seedlings and vegetative growth, choose LED lights rich in a higher blue spectrum for healthy leaf development.


However, transit to lights with a higher red spectrum during the flowering stage to enhance flower formation and fruiting.


Also, monitor lights to have appropriate wattage and light distribution to match the size of your growing space. If you've got a larger area, a good number of LEDs placed at each distance would be a favorable thing to do.


Maintaining a light schedule for plants and putting them at an optimal distance is essential for successful indoor gardening with LEDs. Position the light source at a distance so that light can adequately penetrate the lower foliage without causing heat stress.


As a general guideline, Put lights 12–24 inches above the canopy and adjust accordingly based on the plant’s response. Ideally, LEDs need to be put closer during the vegetative phase, while they should be set farther away during the blooming period.


Also, follow the rhythm of the day and closely adhere to the natural cycle of sunlight by providing 14–16 hours of light per day for vegetative growth and 10–12 hours for flowering. Maintaining a regular light cycle promotes healthy plant development and can help prevent issues like stretching or stunted growth.


Additionally, the color rendering parameter should also be looked at as it accurately defines how light can represent plants in their natural color. Choose LED lights with high CRI so that they can illuminate your canopy with more realistic colors, helping to detect problems in your growing plants.


Reputable brands like Phlizon provide the best PAR (Photosynthetically Active Radiation) output and light system for optimal plant development.

Tips For Optimizing Plant Growth With LED Lights

While choosing the right LED fixture with the above characteristics is essential, there are other advanced techniques to make the most of your cultivation endeavors. Implement these tips for varied, bountiful, and nutritious harvests.


  • Given that the lighting should be in the best interest of the plant, other environmental factors such as temperature, humidity, and ventilation shouldn’t be ignored. A grower must establish an optimal environment that is not too hot or cold to ensure plant health and vitality. High temperatures can cause heat stress, while low humidity can lead to dehydration and wilting, so be mindful of these parameters.


  • A good rule of thumb is to keep the LED fixture at a point where it won't light burn seedlings. You can place your hand on top of the plant leaves and beneath the light source to check for light intensity. If your hand feels hot after a while, it's best to lower the light intensity or increase the distance between light and plant.


  • A light intensity meter can be a significant piece of equipment to add to your growing toolbox. This device monitors the illumination in a given area, so ideally, the grower can work around the value and bring it to an optimal level suitable for plants.


  • Adding a light mover device can be a great working technique for grow lights to cover the entire canopy. This device keeps moving back and forth slowly in order for plants to have an equal spread of light throughout and prevent uneven growth. Studies showed that it enhances the yield by up to 30% and reduces the need to install multiple lights in a single setup.


  • Adopting a supplementing technique like reflective material to reflect light at the lower area of foliage is a great penetration practice that otherwise gets insufficient lighting.


  • Using light strips or LED bars in support of primary grow chambers is ideal for areas where direct light can’t reach, such as the corners of the grow tents and the bottom of the leaves.




Sunlight and grow lights both offer similar functionality to provide light energy to plants so that plants can synthesize essential nutrient compounds necessary for growth. However, today, grow lights become a better substitute for sunlight in terms of productivity, efficiency, and year-round light availability.


It’s genuinely true that sunlight has lighting content that is more efficient for biological growth, but its limited availability and less controllable aspect put many growers into adopting artificial lights.


When talking about the future of farming technology, Full spectrum LED grow lights take the lead because they prove to bring agricultural productivity to the next level and offer a lot of other planting benefits over conventional light sources.


Growers have learned to balance the optimacy of both light sources in order to provide the type of light your crops need to boost healthy development and yield incredible flowers.


1 comment

Feb 04, 2024
Edward Judith Mosshammer

I would be interested in this for a 26′ × 2′ North facing raised bed. I’m limited as to what I can plant because it does not receive full or at least six hours of sun. Would this provide a solution for me and how expensive would it be for the lights and the electricity to run it. Finally, how practical would this be exposed to the weather, I’m in South Florida, so the only weather I would need to be concerned with is rain and wind. Can a rain shield be put over this?

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