Best LED Grow Lights of 2021 Comparison & Review Test Using Laboratory Data
Best LED Grow Lights Table of Contents
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What to Consider When Buying a LED Grow Light?
- How to Measure LED Efficiency?
- LED Spectra and Wavelengths
- LED Wattage and Calculating Coverage Area
- LED Warranty and Durability
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Best LED Grow Lights by Area
- LEDs for 2' x 2'
- LEDs for 2' x 4'
- LEDs for 3' x 3'
- LEDs for 4' x 4'
- LEDs for 5' x 5'
- LEDs for 4' x 8'
- LEDs for Commercial Indoor
- LEDs for Commercial Greenhouse
- Most Efficient LED Grow Lights Test
How to Measure LED Grow Light Efficiency
LED grow light efficiency in umol/Joule (400-700nm) is often stated as micromole per Joule -- or seen as umol/j or PPF/W--means for every joule of electrical energy (Joule = watt x second) a number of photon micromoles are produced. Most entry-level LEDs are between 1.0 and 1.7 umol/j. Higher-end LEDs are usually 2.0 umol/j. 400-700nm relates to the wavelengths of light in nanometers (nm). 400-700nm is the spectral range that plants use most efficiently to photosynthesize. This range is also often referred to as the range of Photosynthetically Active Radiation (PAR).
LED Grow Light Spectra and Wavelengths
LED grow lights can be designed with spectra (plural for spectrum) in many different recipes, as they're called. When thinking about buying a LED grow light it's important to think about what phase you're going to use the grow light for propagation, vegetative growth, flowering phase, or a generalist for all phases of growth, often referred to as 'full spectrum' or 'full cycle.'
Often you will see spectral charts showing what looks like a rainbow of colors on a graph with numbers below it. The numbers below are known as nanometers or thousandth of a meter long. Light waves have changing wave frequencies that cause us to see different colors. Plants have evolved to use mainly blue and yellow to red light spectra to photosynthesize, although they do use other colors including infrared, green, white, and ultraviolet. See the chart below to see an example of a LED spectral chart:
To get you more familiar with LED grow light spectral charts for different phases of growth, below we have the HLG 300L Rspec (flowering phase/full cycle) and Bspec (vegetative phase) so you can compare them. Notice how the HLG 300L Rspec has more relative intensity in the yellow, orange, red area and a little less in the blue.
The HLG 300L Rspec has been designed to focus on the flowering phase, although still has ample blues to use in vegetative growth if desired. See how the HLG 300L Bspec has relatively more intensity in the blues than the Rspec but still has a good intensity in the reds. HLG, like many other LED companies, makes one vegetative-focused light and one flowering/full-cycle light. You'll see other companies do the same when they have two models instead of just one generalist model.
LED Wattage and Calculating Coverage Area
Wattage is commonly used to reference LED fixture size, price, and coverage area. While wattage is a good guideline, it isn't the most accurate way to determine the coverage area of a LED grow light. The most accurate way to measure a light's output is in PPFD (photosynthetic photon flux density AKA umol/j/m2). PPFD can be more simply thought of as the number of light particles (photons) that fall on a given surface each second.
PPFD (umol/j/m2) and DLI is the correct metric for measuring useful light intensity over a given area. Coupled with the correct spectrum for your plant type and phase of growth, PPFD (and spectrum) are the keys to a successful grow. However, for the purpose of estimation, we will report wattage calculations in this article.
When we talk about wattage in this article, we are referring to the wattage drawn at the wall, not what the manufacturer states as "LED wattage" - which is typically the product of the maximum LED wattage and the number of LEDs. For example, 300 x 3-watt diodes would be a 900 watt LED grow light. However, the LED grow light might only draw 500 watts at the wall.
LED Warranties and Durability Considerations
When shopping for a LED grow light, it's important to take these considerations into your purchasing decision:
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What is the length of the warranty of the LED light?
- Most LED grow lights last around 50,000 hours. This usually equates to about 5 years of solid use. If you find an LED grow light that has a 1 or 2-year warranty, then assume it is made with the least expensive LED components available and doesn't expect it to last longer than the warranty period. Most reputable companies will have a 3-5 year warranty for the LED lights.
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If a diode goes out, what is the process to get the fixture repaired or replaced?
- This is an important consideration for your growing operation. Ask yourself, "If my LED light goes out, do I have a substitute light I can use if I need to send my LED light in for repair or replacement?" If the answer to that question is no, you may want to look for fixtures that have modular aspects to them were part of the fixture can be disassembled and repaired/replaced while you can continue to use the remainder of the LED grow fixture. Some examples of modular fixtures are:
- ThinkGrow Model-V 350W Horticulture LED Grow Light
- ThinkGrow Model-H 630W Horticulture LED Grow Light
- HLG 260W XL QB V2 LED Kit - R spec
- HLG 600W QB288 V2 LED Kit - R spec
- This is an important consideration for your growing operation. Ask yourself, "If my LED light goes out, do I have a substitute light I can use if I need to send my LED light in for repair or replacement?" If the answer to that question is no, you may want to look for fixtures that have modular aspects to them were part of the fixture can be disassembled and repaired/replaced while you can continue to use the remainder of the LED grow fixture. Some examples of modular fixtures are:
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Does the LED light have a good way to dissipate heat away from the LED diodes?
- One of the aspects that makes LEDs degrade and fail is heat. If LED diodes don't have a good way to 'exhaust' the heat they produce, then they operate less efficiently and become less reliable. This is a double whammy that you want to stay away from. When shopping for LED grow lights, look for ones that mention a thermal heat management design, spaced-out diodes, underdriving the wattage of the diodes, and heat sinks. We've shown some images below of good examples of LED lights with heat dissipation design and ones with bad heat dissipation design.
Best LED Grow Lights by Area
Best LED Grow Lights for 2' x 2' (61cm x 61cm)
Best LED Grow Lights for 2' x 4' (61cm x 122cm)
Best LED Grow Lights for 3' x 3' (92cm x 92cm)
Best LED Grow Lights for 4' x 4' (122cm x 122cm)
Best LED Grow Lights for 5' x 5' (152cm x 152cm)
Most Efficient LED Grow Lights Test
We're doing something no one has ever done before -- well, sort of. Each LED company that takes its craft seriously focuses on buying high-quality components that will last a long time (read: not fail within 2 years) and have high efficiency/output ratings. To test LED grow lights comprehensively, you really need to send them to a laboratory that will run the light through a battery of instrumentation. Each test form these companies is not cheap. For all the testing that we're requesting, the bill can run up to about $1,500 per light. This was no cheap endeavor, but we wanted to create the most unbiased, comprehensive, and informative comparison review test on the web. Therefore we needed to be using the best equipment available to do our testing.
Lights We're Including In This Test:
- California Light Works GH Pro 340 LED Grow Light
- California Light Works Solar Storm 550 LED Grow Light
- Fluence SPYDR 2i LED Grow Light
- Fluence SPYDR 2p LED Grow Light
- Gavita Pro 1700e LED Grow Light
- HLG 550 V2 R-Spec LED Grow Light
- HLG 650R LED Grow Light
- NextLight Mega LED Grow Light
- Growers Choice TSL ROI-E720 LED Grow Light
- Growers Choice TSL ROI-E420 LED Grow Light
This is not your normal 5' x 5' grid where you use a lumen meter. That can be somewhat helpful, but we're going to use testing done at UL and Light Laboratory Inc., which are independent 3rd party light laboratories that do not have an incentive to make one brand look better than another. These are the same laboratories that most LED manufacturers use to test when designing their lights.
Each test from these companies is not cheap. For all the testing that we're requesting, the bill can run up to about $1,500 per light. This was no cheap endeavor, but we wanted to create the most unbiased, comprehensive, and informative comparison review test on the web. Therefore we needed to be using the best equipment available to do our testing.
The other amazing thing about this test? It's never-ending. That's right, we're going to continually test lights and add the information to this page along with the PDF of results directly from the testing lab. We'll also include information in easy-to-digest tables and graphs below, along with definitions of the terms so you won't need to be an optical scientist to understand what's going on.
There is no one-size-fits-all when it comes to LEDs. We hope this testing helps you choose the best light for you. Also, if you're going to purchase a LED grow light soon, please consider buying from GrowersHouse.com. We put a lot of time and money into this testing to help our customers make informed purchasing decisions. Being a customer helps support our mission of educating fellow growers.
To make it easier on our customer's wallets, we're also offering a 5% coupon good for any of the lights featured in the testing below: GHLED5. Not combinable with other sales or discounts.
Definitions of headings are below the table.
| LED Fixture | Wattage | Efficiency (umol/Joule) [400-700nm] | Total PPF (400-700nm) | Luminous Efficacy (lm/W) | Brand of LED chips |
| California Light Works GH PRO 340 | 332 | 2.61 | 890 | 94.4 | Osram |
| HLG 550 V2 R-Spec | 484 | 2.60 | 1257 | 169.3 | Samsung LM301H |
| California Light Works Solar Storm 550 | 369 | 2.40 | 885 | 42.3 | Osram |
| Gavita Pro 1700e LED | 653 | 2.70 | 1764 | 176.3 | Samsung, Osram |
| Fluence SPYDR 2p LED | 643 | 2.39 | 1536 | 152.4 | Osram |
| Fluence SPYDR 2i LED | 626 | 2.67 | 1669 | 175.2 | Osram |
| HLG 650R LED | 630 | 2.75 | 1728 | 173.9 | Samsung LM301H |
LED Efficiency in umol/Joule (400-700nm): Often stated as micromole per Joule -- or seen as umol/j or PPF/W--means for every joule of electrical energy (Joule = watt x second) a number of photon micromoles are produced. Most entry level LEDs are between 1.0 and 1.7 umol/j. Higher end LEDs are usually 2.0 umol/j. 400-700nm relates to the wavelengths of light in nanometers (nm). 400-700nm is the spectral range that plants use most efficiently to photosynthesize. This range is also offtenly referred to as the range of Photosynthetically Active Radiation (PAR).
Total PPF (400m-700nm): PPF is the abbreviation for "photosynthetic photon flux". It gives the information on the number of photons, which are emitted by a light source. Only photons in the wavelength range from 400nm to 700nm are considered. This is the so-called PAR (photosynthetic active radiation) and photons within these wavelengths contribute to photosynthesis. The unit of the PPF value is µmol/s (quantity of light particles emitted per second). Knowing the PPF value from different light sources allows an easy and objective comparison on the total light output which can in theory contribute to photosynthesis. Please note that the PPF does not consider the direction in which the light is emitted.
Luminous Efficacy (lm/W): A measure of how well a light source produces visible light. It is the ratio of luminous flux to power, measured in lumens per watt. Wavelengths of light outside of the visible spectrum are not included in this measure. The majority of the light plants use to photosynthesize are visible, but there are non-visible spectra that plants also use including ultraviolet and infrared.
Fixture Dimensions: 42.8" L x 46.99" W x 4.3" H (108.7cm x 119.4cm x 10.9cm)
Coverage Area Veg: 6' x 6'
Coverage Area Flower: 4' x 4'
Better for Indoor or Greenhouse? Indoor
Fluence SPYDR 2i PPFD 24 Inches Above 5' x 5' Grid
Fixture Dimensions: 42.8" L x 46.99" W x 4.3" H (108.7cm x 119.4cm x 10.9cm)
Coverage Area Veg: 6' x 6'
Coverage Area Flower: 4' x 4'
Better for Indoor or Greenhouse? Indoor
Fluence SPYDR 2p PPFD 24 Inches Above 5' x 5' Grid
Fixture Dimensions: 44.1" x 43.7" x 2.3
Coverage Area Veg: 6' x 6'
Coverage Area Flower: 4' x 4'
Better for Indoor or Greenhouse? Indoor
Gavita Pro 1700e PPFD 24 Inches Above 5' x 5' Grid
HLG 550 V2 R-Spec LED(discontinued)
Fixture Dimensions: 26" x 20" x 3"
Coverage Area Veg: 6' x 5'
Coverage Area Flower: 4' x 4'
Better for Indoor or Greenhouse? Indoor
HLG 550 V2 R Spec PPFD 24 Inches Above 5' x 5' Grid
California Light Works Solar Storm 550 LED
Fixture Dimensions: 34" x 3.2" x 3.2"
Coverage Area Veg: 6' x 4'
Coverage Area Flower: 5' x 4'
Coverage Area Supplemental: 8' x 5'
Better for Indoor or Greenhouse? Greenhouse
California Light Works GH Pro 340 LED
Fixture Dimensions: 34" x 3.2" x 3.2"
Coverage Area Veg: 6' x 4'
Coverage Area Flower: 5' x 4'
Coverage Area Supplemental: 8' x 5'
Better for Indoor or Greenhouse? Greenhouse
Fixture Dimensions: 29" x 22" x 4"
Coverage Area Veg: 7' x 7' @ 48"
Coverage Area Flower: 5' x 5'@ 30"
Coverage Area Supplemental: 8' x 8'
Better for Indoor or Greenhouse? Indoor
Fixture Dimensions: 37" x 37" x 2.5"
Coverage Area Veg: 7' x 7'
Coverage Area Flower: 5' x 5'
Coverage Area Supplemental: 9' x 9'
Better for Indoor or Greenhouse? Indoor
Growers Choice TSL ROI-E720 LED
Fixture Dimensions: 46.9" x 46.8" x 3.2"
Coverage Area Veg: 7' x 7'
Coverage Area Flower: 5' x 5'
Coverage Area Supplemental: 9' x 9'
Better for Indoor or Greenhouse? Indoor/Greenhouse
Most Yield: California Light Works SolarXtreme 250 LED
The SolarXtreme 250 brings 50w per sq. ft. to a 2' x 2' grow area. This is about as much wattage as you'd want to have from a LED grow light. Its compact LED design makes it great for small spaces.
- Dimensions: 8.5" x 8.5" x 4"
- Wattage draw: 200w
- Watts/sq. ft. in 2' x 2': 50w
- Full-spectrum for all phases of growing
- COB (chip on board) LED types
- Efficiency umol/J: 2.25
- Warranty: 3 years
- Veg coverage area: up to 3.5' x 3.5'
- Flower coverage area: up to 3' x 3'
Best Value: Horticulture Lighting Group HLG 100 V2 LED
The HLG 100 V2 is seriously thin and seriously quiet. Great for those growers who have small ceilings and don't want a bunch of noise from their grow setup all for under $150.
- Dimensions: 13" x 11" x 3"
- Wattage draw: 95w
- Watts/sq. ft. in 2' x 2': 24w
- Comes in your choice of 3000k (full spectrum) or 4000k (veg spectrum)
- Samsung LM301B LEDs
- Efficiency umol/J: 2.43
- Warranty: 1 year
- Veg coverage area: 3' x 3'
- Flower coverage area: 2' x 2'
Most Yield: California Light Works SolarXtreme 500 LED
The SolarXtreme 500 would bring 50w per sq. ft. to a 2' x 4' grow area. Its rectangular design is ideal for 2' x 4' grow tents or spaces, giving an even dispersion of intense light.
- Dimensions: 18" x 8.5" x 4"
- Wattage draw: 400w
- Watts/sq. ft. in 2' x 4': 50w
- Full-spectrum for all phases of growing
- COB (chip on board) LED types
- Efficiency umol/J: 2.25
- Warranty: 3 years
- Veg coverage area: up to 4' x 5'
- Flower coverage area: up to 3' x 4'
Best Value: Prism Lighting Science Stealth 320w LED
The Prism Lighting Science 320w is designed to be an inexpensive option using high-end technology for long, issue-free use. Includes UV and IR spectrum to increase resin output.
- Dimensions: 16" x 9" x 3"
- Wattage draw: 320w
- Watts/sq. ft. in 2' x 4': 40w
- Full-spectrum for all phases of growing
- Double 5w EpiLEDs
- Efficiency umol/J: 1.9
- Warranty: 2 years
- Veg coverage area: up to 4' x 4.5'
- Flower coverage area: up to 3' x 4'
Most Yield: Growers Choice TSL ROI-E420 LED Grow Light
The ROI-E420 uses the most state-of-the-art technology in the LED industry. High efficiency, uniform intensity, and dimmable + controllable with the digital controller sold separately.
- Dimensions: 36" x 35" x 3"
- Wattage draw: 420w
- Watts/sq. ft. in 3' x 3': 47w
- Full-spectrum for all phases of growing
- Water-resistant, designed for uniformity
- Efficiency umol/J: 2.6
- Warranty: 3 years
- Veg coverage area: up to 5' x 5'
- Flower coverage area: up to 4' x 4'
Best Value:Prism Lighting Science Stealth 320w LED
The Prism Lighting Science 320w LED is designed to be an inexpensive option using high-end technology for long, issue-free use. Includes UV and IR spectrum to increase resin output.
- Dimensions: 16" x 9" x 3"
- Wattage draw: 320w
- Watts/sq. ft. in 3' x 3': 40w
- Full spectrum for all phases of growing
- Double 5w EpiLEDs
- Efficiency umol/J: 1.9
- Warranty: 2 years
- Veg coverage area: up to 4' x 4.5'
- Flower coverage area: up to 3' x 4'
Most Output: Gavita Pro 1700e LED Grow Light - 120-277v
The Gavita Pro 1700e has been the best-selling LED light of 2020 and maybe 2021. The Gavita Pro was designed for commercial facilities, but can just as easily work in home grow setups.
- Dimensions: 44.1" x 43.7" x 2.3"
- Wattage draw: 645w
- Watts/sq. ft. in 4' x 4': 40w
- Full-spectrum for all phases of growing
- Water-resistant, designed for uniformity
- Efficiency umol/J: 2.7
- Warranty: 5 years
- Veg coverage area: up to 6' x 6'
- Flower coverage area: up to 5' x 5'
Staff Pick: Growers Choice TSL ROI-E680 LED Grow Light
The ROI-E680 LED light is the first LED made by Growers Choice. The ROI-E680 disrupted the market by offering a highly efficient, controllable LED over 600w for around $900.
- Dimensions: 42.4" x 42" x 2.4"
- Wattage draw: 680w
- Watts/sq. ft. in 4' x 4': 43w
- Full-spectrum for all phases of growing
- Water-resistant, designed for uniformity
- Efficiency umol/J: 2.4
- Warranty: 3 years
- Veg coverage area: up to 6' x 6'
- Flower coverage area: up to 5' x 5'
Most Output: Growers Choice TSL ROI-E720 LED Grow Light
The ROI-E720 LED is the big brother to the ROI-E680. It has increased output along with slightly newer LED diode technology making it Growers Choice flagship LED grow light.
- Dimensions: 42.4" x 42" x 2.4"
- Wattage draw: 720w
- Watts/sq. ft. in 5' x 5': 29w
- Full-spectrum for all phases of growing
- Water-resistant, designed for uniformity
- Efficiency umol/J: 2.5
- Warranty: 3 years
- Veg coverage area: up to 6' x 6'
- Flower coverage area: up to 5' x 5'
Staff Pick Gavita Pro 1700e LED Grow Light - 120-277v
The Gavita Pro 1700e has been the best-selling LED light of 2020 and maybe 2021. The Gavita Pro was designed for commercial facilities, but can just as easily work in home grow setups.
- Dimensions: 44.1" x 43.7" x 2.3"
- Wattage draw: 645w
- Watts/sq. ft. in 5' x 5': 26w
- Full-spectrum for all phases of growing
- Water-resistant, designed for uniformity
- Efficiency umol/J: 2.7
- Warranty: 5 years
- Veg coverage area: up to 6' x 6'
- Flower coverage area: up to 5' x 5'