What Are The Best LED Grow Lights? Well ... that Depends.
How To Choose the Perfect LED Light For Growing Marijuana, Vegetables, and More!
Image: Cirrus LED Sytems Titan 5 LED Grow Light - WiFi controllable spectrum, intensities, and dimming via smartphone app.
So, you want to know what the best LED grow lights are? Well, that depends on many factors. This guide will help you understand the world of LED grow lights and increase your knowledge before you buy that special light(s) for your precious grow. Also, don't forget to checkout our list of the best LED grow lights in 2016 (link below). Happy growing!
Related: The best LED grow lights for 2016
Plant Type and Phase
Low light vs High light conditions
Do the plants need full sun or low-light conditions? Dimmable LED lights may be the way to go for adjusting PAR intensity. Dimmable LEDs (such as Lifted LED, Illumitex, Kind LED K5 series, Simulight, Eonstar) also allow you to vary the light output without adjusting the height of the light and allow you to mimic seasonal light changes that some plants require.
Image: Kind LED XL1000 - Dimmable/customizable spectrum
Vegging vs Flowering
Are you vegging, flowering, or both? There are LED lights for growing that are designed specifically for vegging your plants (blue spectrum lights) and LEDs for flowering your plants (red spectrum lights). Light fixtures with these specific spectrums may also be used in addition to full spectrum LED grow lights or other types of grow lighting to provide an extra boost during veg and bloom phases of your grow. G8LED offers a red booster for that extra flowering boost.
Image: City 14 LED Grow Light by Lifted LED - Customizable spectrum and intensity, dimming, WiFi-controlled via smartphone.
Red and blue light are crucial
If you would like to grow from seedling to flower, then a full-cycle LED grow light is recommended. A full-cycle grow light will provide your plants with the blue and red wavelengths that are needed for optimal growth. Blue light mimics the long day, summer sun and encourages vegetative leaf growth (MH, or Metal Halide, lamps also provide this function). When choosing an LED grow light ensure the unit includes blue lights in the range of 440-470nm. Red light is also important in plant growth. Red light takes the place of the short day, autumn sun. (HPS, or High Pressure Sodium, lamps provide a red-leaning spectrum). When combined with blue light, a hormone cascade is created and the red wavelengths begin to encourage flowering. Look for lights that have red light in the 640-660 range.
Image: Lighting Science VividGro™ V2 - red and blue diodes (red heavy)
UV is a supercharger
In addition to red and blue diodes, you may consider a light that contains UV wavelengths. UV light activates the plants defense mechanisms, affects plant development, growth, and metabolism. UV wavelengths can also increase THC in marijuana plants. Choose LED grow lights that have diodes in the 315-400nm range (380nm is common.)
Some LED grow lights are designed with white LED dioes such as the Diamond Series (Philips Luxeon diodes) by Lil’ Tomato Concepts (LTC), NextLight's Mega LED Grow Light (below), and Pro MAX Grow lights. Quality white LEDs, adjusted for the correct wavelengths and color temperature, provide full-spectrum white light. Make sure that the color of the LEDs (in Kelvins) are in a mid-temperature range. 5500K is a nicely balanced cool/warm color that will provide the blues need for growth and the reds required for flowering. NextLight, LTC’s, and Pro MAX Grow's LED fixtures have been shown to grow from seed to flower with excellent flowering results.
As an aside, the specific wavelengths do not only target the wavelength they are tuned to. LEDs have about a 20nm ‘bleed-over’ on each side of the wavelength (varies with color.) For example, a 380nm diode will fall in the ranges of 360nm-400nm, with 380nm as the peak.
Image: NextLight Mega LED grow light - 650W - white diodes, full spectrum
The best LED spectrums for plant growth
In summary, the best lights for growing cannabis and any other crop will include red and blue LEDs or a full-spectrum white light. UV diodes may be included to enhance a plant's physiological functions, but these are not required. A 6:1 or 5:1 ratio of red to blue is ideal. Most, if not all LED lights on the market today already contain the correct ratio and spectrum, so you do not have to worry about this as you might have when LED grow lights first hit the market pre-2010.
Image: Kind LED Bar Light 4' Flower B - The 'B' (Micro) Versions contain UV and IR
The grow light that you choose should depend on how much area you want to cover. A small 100 watt light may cover 4 sq ft, while a large 400 watt light can cover up to 20 sq ft. Some growers recommend purchasing a larger light, because it is cheaper (watt for watt) and they can always back the light off from the plants if the light radiation is too intense. However, this will also reduce the PAR that reaches your plant so may not be ideal depending on the types of plants you are growing.
A larger light will cover a larger area with more even and intense coverage than a smaller light that spreads the light over a greater distance. For example, the BML Spyder 1200 (pictured above) evenly covers a large area with no hot spots due to its large design.
In addition to the size of the LED grow light, the beam (or lens) angle matters too. A small angle (30 degrees) decreases coverage area, but delivers more PAR to your plants. A large angle (65 degrees) expands the overall light footprint, but reduces the light density delivered to the plants. Apache Tech offers customizable angles on their LEDs --- either 14 or 50 degrees or a blend of both. You might consider larger angle lenses if the light is hung close to the plants. The coverage area will also vary between brands, by the size and shape of the grow light, and the LED wattage.
Advertised LED Chip Wattage
1 to 3 watt chips
Most growth studies suggests that the best wattage for an LED chip is 3 watts. 1 watt chips give off the least amount of heat, and are the most stable and long lasting. However, most 1 watt chip lights may not pack the power required to penetrate deep into the plant canopy. 3 watt LED chips possess the perfect balance between cost, size, and heat generation (or lack-there-of). The light energy that the 3 watt chips expel are able to penetrate up to 5 feet into the plant canopy, which is desired by most commercial growers.
Image: G8LED G8-600 - Award-winning 3-watt chip technology
5 watt chips
5 watt chips are more expensive than 1 or 3 watt chips. They also give off more heat, require larger heat sinks, and must be spaced further apart due their size. Therefore, they can make for an all-around bulky and heavy LED grow light. Yet, you should not necessarily avoid 5 watt chips without some consideration. As the technology advances and prices drop, more and more LED manufacturers are incorporating them into their lights. For example, California Lightworks and Black Dog LED use 5 watt chips and their customers have had great success with their lights. Illumitex offers patented 5.4 watt LED chips in their NeoSol Series LED grow lights. 5 watt chips are becoming more popular as technology drives the cost of these chips down.
Shop LED Grow Lights for Cannabis ›
6 watt chips and beyond
In addition to 1 watt, 3 watt, and 5 watt chips; 6, 8, 10, 50, and 100 watt chips are available. Though these are high wattage LEDs, we do not avoid grow lights that incorporate these powerful LEDs. The LED grow light industry is still young by comparison and many companies are dancing around the edges of current and accepted technology. Many more LED grow light companies will begin to incorporate these high-powered chips into their lights in the form of COB - chip on board - LED design (pictured below). As LED technology advances, COBs are being added to more LED grow lights.
Image: Twilight Group Spider 200w MCOB LED Grow Light - Multiple chip-on-board (MCOB) technology
The truth about chip wattages
But does chip wattage even matter that much if the design is right? The very best LED grow light manufacturers will have patents on their diode or reflector and lens technology. For example, Apache Tech uses 1 watt diodes in their AT120 panels that draw 156 watts total. But, these panels put out high-intensity PAR for the small amount of wattage that they use. Similarly, LED Grow Master Global distributed an LED light bar that contained 190 LEDs and ran off of 9.6 watts, however, it delivered great growth results. Illumitex’s F3 spectrum LED arrays draw 5.4 watts, but their LED grow lights are some of the best on the market (see the video below for an Illumitex testimonial). On the opposite side of the spectrum (no pun intended), Hydro Grow uses 50 and 100 watt integrated chips in their SOL series lights. Their lights have been shown to deliver intense flowering.
LED Grow Light Comparison at DOE Certified Lighting Test Lab
Actual LED Output Wattage
You don't always get what you see
The ‘actual LED output wattage’ differs from the ‘advertised LED output wattage’ by up to 50-75% Companies may advertise that they use 3 watt chips in their LED grow lights, however, the diodes are not powered to full capacity. A 3 watt LED is usually driven between 500mA and 700mA, with most LEDs running at 550mA in order to increase the lifespan of the diode.
Comparing LED grow light power
When comparing LED lights to HID lighting (HPS/MH), use the actual LED output wattage. To get an equal amount of photosynthetic active radiation from LEDs as you would HID lighting, use about 50-75% less wattage than a HID setup. For example, to get 1000 watts of actual LED power you could use 2 LED panels that draw 500 watts of power in place of a 1500-2000 watt HID system. These numbers represent a wide range, and the actual power will differ depending on the brand, diodes, lenses, etc. Most importantly, do not use the advertised wattage of, say, a panel that has 350 x 3 watt chips. This does not equal 1050 watts of actual power. It is closer to 500-600 watts of actual LED power. LED lights will last you 50,000-100,000 hours before the light intensity reaches 70% (L70) and will save you a lot on energy costs compared to HID lighting.
LED base and heatsink
Choose an LED light that contain a metal core printed circuit board (MCPCB). These LEDs incorporate a base metal as a heat spreader and keeps the chips running at a lower temperature. This is important in extending the life of the LED. The LEDs should be mounted to a thick, finned, aluminum or copper heatsink. Most, if not all common LED grow lights on the market have this quality, so it should not be an issue when deciding on and LED grow light.
LED grow lights sometimes contain internal cooling fans to rid any excess heat that may shorten the life of the diodes. However, only about 15-25% of the energy that LEDs output is turned into heat! This is extremely efficient compared to HPS and MH bulbs that expel 80% of their energy as heat. Some greenhouse and research LED grow lights do not have cooling fans due to the low-heat emitting LEDs and/or design. This is convenient because the lights require less power since they are not running internal cooling equipment. Some of the grow light brands that do not have internal cooling fans include GE Lighting, Lighting Science, Philips GreenPower, Illumitex, Pro Max Grow, and LTC. Many growers prefer no cooling fans, because it is one less part that could potentially break on the unit.
High-quality LED grow lights are made with a metal (typically aluminum) housing. If the unit is plastic do not purchase it. Aluminum is an excellent heat conductor and helps transfer excess heat that is produced by the LEDs.
Look for grow lights that contain a ‘constant-current’ driver, as opposed to a ‘constant-voltage’ driver. An LED's voltage tends to drop as they get warm. A constant current driver will keep the current steady as the LED voltage changes with the increasing temperature. This will extend the life of the diodes.
Return policy and Warranty
Return policies on LED lights will vary and range from no returns to 90 days (most common). A 3 year warranty on your grow light is ideal. Some companies even offer 5 year warranty, such as Illumitex, NextLight, and Lighting Science.
You get what you pay for
When buying and LED grow light, you get what you pay for. Good companies make good lights. If you buy ‘no-name’ lights from eBay, Amazon, or Alibaba you will get a unit that burns out fast. The brands that we sell at LED Grow Lights Depot have made many growers happy --- just check out the reviews of some of these lights online. Some are smaller companies, some larger, other from China, and some are U.S. made. Many well-constructed LED grow lights are designed in the U.S. and manufactured in China. Some of these brands include Black Dog LED, Kind LED, Illumitex, and Lighting Science. There is nothing wrong with this, because often they are made to an American company’s specifications and whether they are or not, these lights have proven their worth. Other brands, such as Mars Hydro are designed and manufactured in China and are great lights - especially considering their inexpensive cost compared to other LED grow lights.
Image: Black Dog LED PhytoMAX 800
Lumens and PAR
Lumens are for Humans
You may have seen LED grow light information listed in Lumens and PAR. Lumens do not matter --- at least not to a plant. Lumens are a measure of the amount of visible light emitted from a source. Chlorophyll mostly absorbs light in the blue range, red range, and far ranges of the visible spectrum. Chlorophyll does not absorb green or yellow wavelengths (although evidence suggests that green light helps drive photosynthesis). In sum, lumens do not tell us how well plants will respond to visible light.
Par sets the Bar
PAR, or photosynthetically active radiation, is a measure of photosynthetic light energy (400nm-700nm range) that falls on the plant each second. PAR does matter. It is important for plant growth, yet, many cheap PAR meters read the entire PAR range and not just the wavelengths required for photosynthesis.
A spectroradiometer is the best tool used to measure PAR, especially for when comparing LED grow lights to fluorescent, HPS, or MH systems. A spectroradiometer measures the energy at each specific wavelength.
It is best to ask the manufacturer how they obtained their PAR readings. When you know the umol readings (PAR/PPFD) for a grow light you are able to place it at the correct heights for optimal PAR coverage.
For a further discussion on PAR, PPF, PPFD, and DLI see this page.
Do LEDs Work for Growing Plants and Flowering Cannabis?
Yes. They certainly do! Keeping the above points in mind when purchasing an LED grow light will ensure that you buy a light that will grow your plants well. Remember that LED grow lights can be designed for different uses (veg / flowering / full cycle), so make sure that you are purchasing the correct LED spectrum for your growing needs. It is always best to go with a full cycle light (all brands offer a full cycle light) if you are unsure of what you need.
Image: Advanced LED Lights XML 650
LEDs past and present
You may have seen many claims on the internet stating that LED grow lights do not work that well for flowering marijuana. This is not true anymore. In the past, LEDs were not adjusted for proper growth and flowering when they first arrived on the market not too long ago. Small-operation growers lost money and valuable harvests, and shunned away from LED lights. They stated that these lights were a waste of money. Hearing their claims, more testing was done at LED manufacturers and the correct spectrums for plant growth and flowering were developed. Now there are many LED grow lights that successfully grow and flower marijuana plants. If you decide to purchase lights for growing marijuana, please double-check that they have some backing --- that other growers have had success with these lights. Do not believe the marketing hype that many companies shout. Reviews, testamonials, forums, and word of mouth will be your best references!
We, at LED Grow Lights Depot, can not say that all of the lights we sell are used or have been used for growing marijuana. That is to say, that some are used in greenhouses and hydroponic systems for growing vegetables. If you want more information on the best LED grow lights for growing cannabis or for other horticultural purposes, please contact us or see this informative page on the best LED grow lights of 2015 or the best LED grow lights of 2016.
LEDs are the future
The LED grow light market is taking off! At first, many insufficient LED grow lights were sold to consumers. These days, we have many great LEDs that grow better than HPS and MH systems. As time goes on, the market will drive the ‘bad’ LED grow lights out and favor the LEDs that perform well. Also, LED technology will continue to improve and costs will drop, passing the savings on to the consumer. Right now, start-up costs for growing using LEDs can be high, but the investment of a quality light should last you at least 10 years! You can’t say this about traditional grow lighting. The cost savings of an LED light will usually come after about three years, but sometimes less than one! However, this number will depend on many other factors, for example: the size of your grow and HVAC system. Given some time, LED grow lights will replace traditional HPS and MH bulbs in nearly every grow room and greenhouse.
With all of the above points in mind, you are on your way to choosing the very best LED grow light for your money and crop.
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Are you a beginner grower? You might also be interested in the following books:
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Read Next: The best LED grow lights for 2016
Note: Please be aware that the cultivation of certain plants may or may not be legal within your own specific region or country. LED Grow Lights Depot does not encourage or condone any illegal activity and advises each individual / user to inform themselves of the relevant laws within their own region/country.