How LED Grow Lights Work - Everything You Need To Know

What is an LED Grow Light?

As suggested by their name, LED grow lights are luminaires utilizing LED chips in a modern and efficient way to produce light for growing plants. The first LED grow lights had relatively low light output and limited selections of colors while modern LED grow lights have high brightness and come in varieties of colors in visible, infrared and ultraviolet spectral ranges.

A full-spectrum LED grow light, which is currently the most popular grow light most indoor growers use, is a term that implies that your grow light closely resembles light from the sun. This term came from the concept of “full-spectrum light,” which has been used to refer to electromagnetic radiation from the UV to IR wavebands.

A full-spectrum lighting system, especially that which contains lights of all wavelengths, like (UV, and IR), are far more effective and practical. UV and IR diodes aid you're plants in the flowering process and can help increase yields. While also improving the smell and taste.

The History of LED Grow Lights

LED grow lights in the early stages were rather impractical and cost inefficient. With the newest advances in technology, LED grow lights have now become the best grow lights on the market.

Full Spectrum LED grow lights for example, are the newest technology designed to replicate the only real full-spectrum light source, the sun.

The commercial lighting industry began using the name “full-spectrum” to sell lights that produced a Color Rendering Index (CRI) over 90. Humans perceive colors more accurately under light sources with a CRI over 90, much like how we see colors in our natural world under daylight.

How LED Grow Lights Can Stimulate Plant Growth

Photosynthesis depends upon the absorption of light by photoreceptors and pigments in the leaves of plants. The most well-known of these pigments is chlorophyll-a, but there are many accessory pigments that also contribute to photosynthesis.

The relative light absorption of chlorophyll pigments is one of the reasons why red light has become popular among LED grow lights. Not all PAR light contributes to photosynthesis equally, though we now understand that other wavebands of light such as green, do play an important role in this process.

Since photoreceptors in plants also have their own ranges for light absorption, they co-regulate processes that create plants’ form and structure depending on the spectral mix they receive.

For instance, higher ratios of blue light can induce more robust root growth, more favorable plant biochemistry, and a hardier structure. But these effects may not be as pronounced when more red light is introduced.

The Best LED Grow Light Spectrum for Plant Growth

Plants only require PAR light for photosynthesis. So, if your grow light is optimized within the PAR spectrum, you’re going to get the most bang for your buck when it comes to minimizing electrical costs while maximizing plant health.

Beyond PAR, it’s important to choose a light spectrum that’s:

  • best for the environment you’re growing in (greenhouse or indoors)

  • tailored to your plant’s growth phase (propagation, vegetative, flowering, or finishing)

  • specific to the cultivar being grown

Although you cannot mimic sunlight, you can still use the LED light spectrum to you're advantage. Luckily, there are many grow lights available with designs intended to do just that. Lets take a look at some of the advantages of LED grow lights.

Advantages of LED Grow Lights

LED Grow Lights Are Highly Efficient

For grow lights, efficiency is measured in µmol/j or, more simply, the amount of photosynthetically active photons that are produced per watt consumed at the wall. This can also be interpreted as µmol per watt.

The energy saving that growers can expect from using a very efficient LED grow light, instead of an HID grow light, is around 48%. This percentage may drop to as low as 20% with less efficient LED grow lights.

LED Grow Lights Produce Less Heat

LED grow lights produce significantly less heat. This means you won’t spend as much energy on cooling with an air conditioner.

It also makes them better for growing in small spaces. This gives them the ability to be placed closer to plants due to the low heat output, sometimes as close as a few inches!

This is advantageous to growers growing in areas limited by height. This feature also allows growers to place the lights closer to plants to ensure optimal light penetration deep into the canopy.

LED grow lights can also be fully recycled, making them an eco-friendly alternative to HID lights. HID lights contain fairly high amounts of mercury, which can be very harsh on the environment and you're plants – especially when it’s burned.

LED Grow Lights Are Environmentally Friendly

LED grow lights can also be fully recycled, making them an eco-friendly alternative to HID lights. HID lights contain fairly high amounts of mercury, which can be very harsh on the environment and you're plants – especially when it’s burned.

Other Advantages of LED Grow Lights:

  • come in a variety of sizes

  • intense full spectrum light capabilities

  • variable sizes for customized growing spaces

  • highly efficient watt to lumen ratio

  • long lifespan

The Different Kinds Of LED Grow Lights

COB LED Grow Lights: A COB (short for Chip-on-Board), is an LED packaging technology that describes mounting multiple LED chips directly onto a substrate to form a single module. Multiple LEDs, minuscule in size, are wired and packaged together into a single ceramic or copper board so that they function as a sole light source.​

When a COB LED package is energized, it appears more like a lighting panel than multiple individual lights as usually the case with other LED packages, like when using several SMD LEDs mounted closely together.​

One of the main reasons that COB LED grow lights have made their way so quickly into many grow rooms is because of their HIGH Color Rendering Index (usually over 80) and broad spectrum.

CRI stands for Color Rendering Index, and describes how the color of a light source changes how an object appears to the human eyes and how well subtle variations in color shades are revealed. The higher the CRI, the more realistic things look.

Regardless of the COB manufacturer, whether CREE, Citizen, Bridgelux, etc. They all offer at least 70 CRI Broad Spectrum chips and which usually can go to up to 97 CRI.

This means no purple, or extreme orange, or red or yellow but high quality white light showing realistic colors.​

While COB LEDS do provide an excellent light intensity, they’re not exactly the best when it comes to spread, because COB LEDs are a single-point light source (meaning all light comes from a single point in space) The warmer ones are better for flowering, while the cooler ones are better for vegging. Many fixtures will include a mix of both.

Quantum Boards: Which deliver the same color spectrum, but do so using many small diodes spread out over a large area, instead of using a few extremely powerful diodes.

Quantum boards also have much more even coverage, due to their large size. This means plants throughout the grow area get large amounts of light, which also leads to bigger and better yields.

As good as the all-white spectrum is, there is an even better mix of colors. That is the all-white spectrum mixed with additional red and blue diodes, as well as UV and IR.

Let’s take a look at the best plant lights on the market that mix white quantum boards with additional diodes.

1. Spider Farmer

These grow lights are very powerful in all the best ways when it comes to LED grow lights in 2021.They are very efficient when it comes to energy, costing lower than most of today’s LEDs but still offer great performance.

They come in 3 sizes, One for a 2ft x 2ft area, another for a 2ft x 4ft area, and the biggest one which is rated for a 4ft x 4ft area.

There built with reliable components including a Meanwell driver and Samsung lm301b diodes. There also capable of daisy chaining and multi dimming which is a nice feature if you need multiple lights.

There's no built in fan so no need to worry about noise. Watch out though, cause they can get really hot to the touch.

Overall the Spider Farmer is one of the best bangs for you're buck, as it offers superior light output and gives off very low heat.

Which in my opinion makes it automatically better than using the purple spectrum or HPS. All in all a quality and reliable product.

2. Atreum Hydra 1000

This grow light is so far the only grow light I know that is built with a different diode pattern. The diodes have been stretched to the corners of the light. Which is designed to promote an equal light coverage and ensure an even canopy.

Doing this can help you increase you're yields by providing you're plants with the proper light intensity they need to fully flower.

The grow light only comes in 1 size, and that's a 2ft x 2ft area. Which means if you have a bigger grow tent, you are going to need to buy multiple lights.

It's built with reliable components including Samsung lm301b diodes and a Meanwell Driver. Which is what I like to see.

Another thing that is really different about this grow light is that it has a read-out number next to the dimmer that shows you exactly what percentage of power the light is using.

Overall this is a great grow light, it offers something other grow lights do not have, and that's what really makes it stand out.

3. Sonofarm

The Sonofarm is overall one of the best LED grow lights when it comes to value and price. The build quality looks and feels nice, offering solid performance at a relatively low price.

It has reliable components including a Meanwell driver and Samsung lm301b diodes.

It also includes a dimmable knob with an on/off button for easy control.

It Has a very thick heat sink for better heat dissipation. Price point is lower than other competitors and includes a 5 year warranty with a rated 100,000 hour lifespan.

This grow light comes in 3 sizes, a 2ft x 2ft, 2ftx 4ft, and a 4ft x 4ft. The Sonofarm makes an excellent choice for those who are looking for the best of the best at a relatively low price.

4. Mars Hydro SP3000

This Mars Hydro light is overall one of the strongest full spectrum lights you can buy. The light comes completelymbled and ready to go, no need to wire anything up.

This grow light has the best components, and is overall one of the best options if you are growing in a 2ft x 4ft area. I recommend using a grow tent to get the maximum harvest.


Its built with Samsung LM301B & Osram 660nm Diodes, UV & IR diodes, and a MeanWell Driver. It can also daisy chain (up to 15 lights connected) and IP65 Waterproof.

Mars Hydro has a pretty good selection of grow lights that are actually not bad for the price. They have really improved over these past few years, and their SP3000 Series proves that. Which offers great quality for price value.

5. Mars Hydro FC

These grow lights are some of the best LED grow lights out there and offers something not really seen before.

They have a bar styled design, which has improved light coverage compared to a quantum board. This can seriously help you when trying to have an even canopy and will help increase yields.

It has a removeable driver which is something new, and helps keep the driver from over heating. it also comes with a dimmable knob and on/off for easy control.

There are 3 sizes of these grow lights, A 3ft x 3ft, 4ft x 4ft. and a 5ft x 5ft. It's built with reliable components including an Inventronics driver and Samsung lm301b diodes.

These grow lights are overall some of the best LED grow lights available. There

well built, can daisy chain, and offer great light coverage. These are grow lights that will last many harvests and will surely help you in the short and long term.

So, Why Choose an LED Grow Light?

LED grow lights are the lighting of future agriculture. They are not only economic in their use but they produce better plants as well, in comparison to all traditional lighting options.

When set side-by-side with the traditional HPS (high-pressure-sodium) systems, LEDs win in terms of energy efficiency, the quality of plants cultivated as well as environmental friendliness.

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