Can Any LED Light Be Used As An Indoor Grow Light?


The invention of LED lighting has revolutionized the lighting industry, making lights more energy-efficient and cheaper. In the hydroponics and indoor growing industry, grow lights are typically very expensive, and some generate a lot of undesirable heat. Has the LED revolution impacted the grow light industry, and can any LED light be used as a grow light?

Not all LED lights can be used as grow lights. Plants need a full spectrum of light from 400nm to 700nm to flourish. LED lights that cover this spectrum are good for use as grow lights and provide the necessary light wavelengths promoting good overall growth, flowering, and fruiting of plants.

LED lights are certainly cheaper and more energy-efficient than many other lighting types, but the requirements that the plants have from the lighting spectrum remain the same. An Led light used as a grow light must offer the plants the best spectrum of light for growth, and not all LEDs offer this benefit.

LED Types
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What LED Grow Lights Work Best?

While you can use domestic LED lights for grow lights, you would do better to get purpose-built LED grow lights that come in a bank for better distribution of the light and the correct intensity.

Indoor hydroponics is growing in popularity, which means that grow light manufacturers are building lights that cater to all sectors of the market. Many manufactures make lights that are switchable from blue light to red light and to full-spectrum white light.

An example of this is the Phlizon 1200W Double Switch Series Plant LED Grow Light which has this switching capability. This gives you the flexibility of only growing under full-spectrum light while you learn the ropes of indoor growing. Once you feel comfortable experimenting with different lighting, there is no need to buy additional lighting, as this unit allows switching between modes. 

Phlizon 1200W Double Switch Series Plant LED Grow Light for Indoor Plants...
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The Growstar 2000w Led Grow Light with Full Spectrum Wavelength is another example of a full spectrum grow light, but this model is not switchable. The advantage, though, is that it covers the full PAR spectrum and includes infrared wavelengths as well.

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  • High Efficiency Energy Saving Plant Light: Our 2000w led grow light consuming only 220 watts...
  • Higher Ppfd Value: 2000w grow light’s Diodes offering a high efficacy rating of ppf per Joule...

Can LED Lights Be Used As Indoor Grow Lights?

Light-emitting diodes or LEDs are a great option for use as a grow light. Many of the traditional grow light solutions are expensive, and some generate a lot of heat, which is not only problematic for the plants but also a possible fire hazard.

In the early days of indoor plant growing, incandescent lights were used because they were the only lighting technology available at the time. These light sources produced heat, and the spectrum of light offered was less controllable. This was considered the first generation of grow lights.

Second generation lighting came in the form of fluorescent lights. This lighting method is still popular today, but the light produced is normally only suitable for herbs and vegetables. The advantage of fluorescent lighting is the very little heat is produced, and a wider choice of light spectra is available.

The third generation grow lights are the HID or high-intensity discharge lights, which were mostly developed specifically for indoor plant growing applications. These lights include metal halide (MH), ceramic metal halide (CMH), and high-pressure sodium (HPS) lights, among others. These lights are expensive, and some produce huge amounts of heat, which can be problematic for indoor growers.

The fourth generation of grow lights is LED lights. LED technology is cheaper, has less associated heat than any of the older generation grow light technologies, and has more flexibility in the spectrum of light provided.

LED lights have quickly become the most popular form of grow lights, although some growers, especially commercial growers, often use a mix of LED and third-generation grow lights.

As a home grower, LED lights are the perfect light source to use for growing plants indoors. They are cost-effective from a purchase price point of view as well as an energy use point of view, and they generate little to no heat.

We have established that Led lighting is suitable to be used for grow lights, but will any LED light do the job to provide the light your plants need to flourish?

Are LED Grow Lights as Good as Sunlight?

Although natural sunlight is the best lighting for plants, this is not an option for indoor plant growing. Sunlight contains the full spectrum of natural light, but plants do not make use of the entire spectrum.

Many plants make greater use of certain spectra of light during certain growth phases of the plants. This knowledge gives us flexibility in our lighting choice for growing plants indoors.

We can choose to provide the plants with an abundance of the spectra that they need during certain growing stages to maximize their growth, or we can simply provide them with a light that offers all the spectra of light, and the plant only uses what it needs.

Considering that plants need a certain range of the light spectrum for optimal growth, not just any LED light will do as a grow light.

Choosing the correct spectrum LED light or a range of LED lights will give you the best expectation for success in growing your plants indoors.

To understand which LED lights will be best for your plants, you first need to understand what range of light plants need to thrive so that you can get the correct lighting and achieve predictable growth results with your lighting choice.

What Spectrum Of Light Do Plants Need?

Plants utilize a wide range of the visible spectrum of light, and as scientists study this aspect with more advanced testing equipment, they are discovering that plants use more of the white light spectrum than we first thought.

Early studies seemed to indicate the plants did not make use of the green spectrum of light at all, but this has since been shown to be untrue. Granted, plants do not use much green light, but they do use some of it as part of the trigger for their photosynthetic processes.

Studies have also indicated that plants actually benefit from the invisible spectrum of light, such as UV and the far-red spectrum. Studies have indicated that the UV and far-red, or infrared spectrum of light help to increase the plant’s resistance to disease and to pests.

Fortunately, when growing plants indoors, much of the risk of disease and pest infestation is eliminated because of the controlled growing environment. This is not to say that pests and disease cannot be a problem for growing indoors, but the risk is greatly reduced. This means that the ultraviolet and far-red spectrum is less important for plants growing indoors.

The spectrum of light that has come to be considered the most important to indoor plants flourishing is the range of light called Photosynthetically Active Radiation or PAR. This range of light covers most of the range of visible light and includes from the low end of the spectrum from 400nm all the way up to the higher end of the spectrum at 700nm.

The PAR range includes blue light, a high energy radiation, to red light, which is a low energy radiation. The wavelengths within this range are considered to be the best range to support photosynthesis processes in plants. Read more about Red and Blue LED Grow Light Spectrum in our full article

Photosynthesis is the process in plants whereby the nutrients that are absorbed by the roots are converted into forms that are useful for food for the plant. The energy needed for these processes is derived from the light that the plant, leaves, or the chlorophyll in the leaves absorb. 

As a result, a reduction in photosynthesis processes will result in stunted growth of the plants, unhealthy plants, and plants that are not capable of flowering or fruiting.

The right spectrum of light is not the only factor in creating a healthy light environment for your indoor plants. The quality of light is one factor, but the intensity of the light also plays a major role in the success of your indoor lighting for plants.

Low-intensity light or uneven distribution of the light will negatively impact the growth of the plants. This is why many indoor grow lights come as a bank of lights rather than a single light source.

Why Do Indoor Growers Use Different Color Lights?

As we have seen, plants need the full spectrum of the PAR range from 400nm to 700nm to flourish. However, in various stages of a plant’s growth, it uses more of one part of the spectrum than others.

For example, red light is used extensively during its flowering and fruiting phases of growth, while blue light results in strong root development, sturdy stem growth, and larger, healthier leaves.

For this reason, indoor growers may use different color grow lights at different stages of the plant’s growth to maximize the required light available to the plant during the various stages. 

Thus, a grow light with a bluer spectrum will be used for seedlings to enhance root, stem, and leaf development, and a light that is heavy on the red spectrum will be used when the plant starts to flower or produce fruit

Full-spectrum lights will still be used during interim growth periods to provide a spread of the light spectrum for the plant.

In food plants, blue light has shown an increase in the number of antioxidants and certain vitamins in leafy plants, such as lettuce. Exposing the plants prior to harvest to lights that have more of the blue spectrum light can enhance the nutritive value of these plants.

Does this mean that you have to invest in a range of colored lights and swap them out during different growth periods of your plants? No, this is not necessary, particularly if you are growing food crops indoors for your own consumption.

It is usually commercial growers that use these different lighting arrangements in different growth stages to maximize their growth, yield, and, therefore, profit

However, as you get into the indoor hydroponic growing niche, you will be tempted to experiment with your crops to see how you can get the most out of your plants. Hydroponics quickly becomes a hobby rather than just a way to grow your own food!

What Is The Best Spectrum For LED Grow Lights?

As we have seen, LED lights can definitely be used as grow lights for your indoor hydroponics, but some LED lights are better for this function than others.

The best LED lights for average indoor home growing operations will be a broad spectrum light that covers the full PAR range of 400nm to 700nm. This light will give you the most flexibility, and the plants will absorb the spectrum that they need from the light without you monitoring growth and changing lights at different stages.

It is also more cost-effective to buy a single light set in the broad spectrum range rather than several light sets, which would have to include red, blue, or purple grow lights and a full spectrum light.

LED lights that are intended for domestic use for lighting in the home generally only offer limited ranges of the PAR spectrum. When you examine domestic LED lights, you will often see a number expressed on the box in Kelvin, something like 6500K, for example.

What Are Kelvin Units For Grow Lights?

The Kelvin unit is used to describe the “temperature” of the LED light, so when you see a grow light described as “cool white,” it is an indication of the color temperature or ambiance that the light offers.

The Kelvin ratings are as follows.

  • 2700K to 3000K. This is a soft, warm white color that incorporates more of the yellow to red spectrum of light.
  • 3500K to 4100K. This is a neutral white light which is more convenient for workspaces. This light carries a broader spectrum of light.
  • 5000K to 6500K. This is a cool white light that is high in the blue spectrum, giving the light a slightly blue tinge. This light is good for reading and high contrast.

Most grow lights do not use the Kelvin rating, but many people starting out will try this as a cheaper option before investing in proper grow lights.

If you are going to go this route, you will need three lights, one in the range up to 3000K, one in the range up to 4100K and one in the range up to 6500K. This will give you the correct mixture of light wavelengths to cover the PAR spectrum.

Conclusion

LED lights have been a major advancement in the lighting industry as well as the indoor growing industry. LED lights can be manufactured more cheaply than other lights, provide greater coverage of the light spectrum and generate significantly less heat!

These characteristics make LED lights perfect for indoor growing operations. However, not all LED lights are suitable for use as grow lights. Some domestic LEDs do not cover enough of the PAR light spectrum to be useful to the plants.

If you use a range of domestic LED lights, you can get the necessary spectrum coverage, but it would be more productive to purchase a set of purpose-built LED grow lights that give more flexibility and better light intensity for growing plants indoors.

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