How LED Grow Lights work: Everything You Need To Know

Everything you Need to Know About How LEDs Generate Useable Grow Light

LED Grow lights have come a long way in a very short amount of time. The technology required to produce enough usable light wasn’t obtainable until just recently. Unfortunately for consumers, many LED companies toted their LED grow lights as more powerful than HID (High-Intensity Discharge) lights when they were not. These early misleading statements lead to a negative consumer sentiment that lasts to this day. Our LED Grow Light Reviews will help you pick a grow light that will grow cannabis extremely well.

How LED Grow Lights Work

I’ve been growing with and testing LED grow lights for 4 years, I’ve tested many of the early LED grow lights that were more than disappointing and often catastrophic to the test plants being grown under them. In the past year or so there has been a significant change in the LED grow light technology available and this has opened the floodgates to high quality, high powered LED grow lights on the market.

You Can Replace Your Old-Fashioned HPS System

At this point LED grow light technology though more expensive than traditional HID (High-Intensity Discharge) lights, is now capable of replacing your current HID setup. There will be some skepticism to that statement, but I’ve had over 8 grows with current LED technology and have found that I have had no loss in crop yields, in fact, I’ve seen small increases in cannabis yields.

You don’t have to take my word that LED is as good as HID lighting, I’m going to explain the confusion over LED power output and you’ll see for yourself.

Are LED grow lights worth the investment?

Led grow light technology has come very far in a relatively short amount of time. While it’s true that LED grow lights got a bad rap because of early manufacturers claims that didn’t hold up, but that has all changed with the newest LED releases. The technology that supports fantastic plant growth is finally available to you.

LED’s do cost more than traditional HID lighting systems up front but the large energy savings you experience will bring the initial investment down in a hurry and make it well worth your investment. Light Emitting Diodes or LED’s are more than just lower energy grow lights, they or super-efficient at producing light and this leads to a large reduction in the amount of heat generated by the light unit. That means not only saving from the grow light but from needing fewer cooling fans to control the temperature of your grow area as well.

I’m a convert to LED grow lights, I saw the potential early on but dealt with poor quality LEDs which were terrible for growing cannabis. I stuck it out though and I’m glad I did. I was right about the potential of this technology that we are just starting to experience in the last 2 years.

I guess the best place to start if you want to know more about LED grow lights is to look at the technical aspects of an LED and how they work. I like to think of an LED grow light as a structure that holds tiny semiconductors or diodes which restrict the flow of electrons when power is provided. The process of restricting the flow of electrons causes the diodes to emit light, an incredible amount of light. Cannabis plants absorb this light and convert water and carbon dioxide into simple sugars which the plant then feeds on.

While its true other types of grow lights convert electron energy into usable light for plants but no other option is more efficient than LED. Much of the energy used by HID lights (high-intensity discharge) is converted to heat instead of light. Heat can be useful to your plants but too much heat means you need to have more fans and ventilation to prevent your plants from getting too hot. Cannabis should really be grown in temperatures between 75 and 85 Degrees for best effect.

More Light Spectrums = Better Cannabis Plants

Another important development in LED grow lights has been the ability of the manufacturer to be able to tune the light their LED’s provide. Plants and in this case cannabis plants need more than one or two colors of light to thrive. Early LED grow light contained only blue and red LED’s which was the cause for their poor performance. These two band LEDs are known for their characteristic purple hue which makes it very hard to view your plants while the grow light is on.

full spectrum LED wavelengths

Since the early day’s engineers have been able to add at first 12 bands of light and now wideband technology has extended that to 24 bands of visible and invisible light which plants are able to use for growth. New LED options such as the ES300 Electric Sky provide wide-band light which includes all the light spectrums that a plant can absorb and convert to growth energy. These new wide-band lights are a game changer, look out for them in the near future.

What should you do?

The future for LED is so bright you just got to wear shades. LEDs are the right choice for you because they are extremely energy-efficient, long-lasting and provide tuned light spectrums to meet your plants light needs completely. While it’s true that other light options such as T5 fluorescents are almost as energy efficient as LED technology they do not provide the same levels or quality of light. A T5 light is the most common options people will use to grow cannabis. While these lights are fantastic for seedlings and young vegetative plants they do not provide enough light bands or energy for quality flowering. Spiral fluorescents provide about the same amount and type of light energy as the T5 option.

Remember though that light is actually the food for your plant, without it there is no plant, the more of the correct light spectrums you provide the better your plants will grow. Nutrients are great to support your plant’s growth but in the end without light nutrients aren’t even needed.

People often use T5s and spiral fluorescents because of their low cost and easy access.

I’ve got a little sidetracked here, let’s get back to the big question “what should you do”? Let’s get down to brass tax, are LED grow lights worth the higher upfront cost investment? The answer is a big “yes” as far as I’m concerned. I’ve been growing with LED’s for several years and the light units I’ve been testing in the past year are light years better than grow lights from even two years ago.

So why are LED Grow Lights Better Then HID Lights?

Back to the million-dollar question is it worth paying a premium to use LED grow lights over conventional grow lights? There are several factors we need to examine to determine if LED’s are the way to go. You might be content growing with your fluorescents or high-intensity discharge units so why the heck should you upgrade?

LED technology uses about 30% less electricity while producing the same amount or more light energy than your fluorescents or high-intensity discharge units. The savings add up very fast when you are running high wattage grow lights for 18 hours a day.

LED grow lights have a life expectancy of over 50,000 hours of usable grow light. You’ll start saving money on replacement bulbs after only 2 or 3 grows when its time to change your bulbs as they start to lose growing power.

LED grow lights are so efficient at converting energy into light that they produce much less heat then traditional incandescent and fluorescent grow lights. Having your light producing less heat means you need less air exchange within your grow area to maintain a comfortable temperature for your cannabis plants.

New wide-band LED technology provides your plants with more bands of light that are used by your plants for energy.  Older LED lights provided a very narrow spectrum of light that was heavily focused in the red and blue spectrums. You’ll likely recognize the purple hue older LED units created. Wide-band spectrum LED grow lights look white to warm in color to the eye. To the plants, these lights are providing light from the 300nm to 780nm spectrums.

How Much Light Power do I Need?

To grow cannabis vigorously with LEDs you are going to need 20 or more watts of power per square foot of grow area. So, for example, a 4×4 foot grow area is 16 square feet and would require 320 watts of power at the wall.

LED manufacturers at large label they’re led grow lights capacity based on the total wattage of the diodes installed on the light. Those diodes are never actually powered to their full capacity, so the more accurate power measurement is watts at the wall when it comes to LEDs.

How is LED Light Measured?

The confusion generally starts here for people trying to learn about LED grow lights. Manufacturers of LED grow lights inflate the growing power of their products by adding up the total maximum output of each diode their grow light contains. The issue becomes that the diodes are never run at maximum power and are usually run at 80% of their maximum output. Think of it like a car engine, you can’t just hold the gas peddle down without blowing up the car, it’s the same issue, running diodes or overdriving them seriously affects the life expectancy of the grow light unit.

Lumens Aren’t an Accurate Measurement of Light Produced

You might think that lumens would measure grow light but in actual fact lumens only measure light brightness or how much light is emitted by a light source. There is so much more going on though then just brightness.

An Introduction to PAR: An Accurate Measurement of Grow Light

Lumens is just not an accurate measurement of useable light for growing, therefore, we have the measurement PAR. PAR refers to only the light spectrums that power photosynthesis and not necessarily are seen by the human eye. Par is measured in micromoles or light per square meter per second.

PAR is the amount of light available to be used for photosynthesis which creates energy for your plants to convert light, water, and nutrients into food.

Vegetating plants respond best to the color spectrums blue and red which are found on the light spectrum between 340nm and 740nm. As the plants mature and start to flower they require more red light and less blue; on an LED unit this is usually as simple as flipping a switch.

Photosynthetic Photon Flux (PPF)

PAR value is the photosynthetic photon flux, measured in micromoles (μmoles) per meter squared per second. I know, that’s a mouth full and I don’t blame you if you feel like bailing on this. You don’t need to know this to grow but if you are a geek like me you might want to know how this all fits together.

PPF is a metric which is used to describe the number of photons that strike your plant’s photosensitive surfaces per second. Sunlight has a PAR value of 1200-1400 micromoles (μmoles). A grow light that promotes vigorous healthy plant growth would have a par value of between 800 – 12800μmoles Using artificial grow light above 1280μmoles will cause damage to the plants and result in poor growth or even death of the plant.

Light Intensity Isn’t Everything, Color Counts Too

The color of light or the wavelength of the light spectrum produced by a grow light unit is as important as the intensity of light produced. Cannabis plants use light from many light spectrums from 340nm to 740nm to power photosynthesis.

Most modern LED grow lights produce light between 400 and 700nm with some of the higher end wide-band lights producing 360 to 740nm of color. Cheaper units will produce a smaller spectrum of grow light compared to multi-spectrum lights that contain between 9 and 12 grow spectrums. Generating light beyond these spectrums is a waste of power consumption because your plants can’t convert it to energy.

LED’s can also produce UV and IV light which traditional HPS or MH lights can’t produce. These invisible spectrums of light have advantages in small amounts. These spectrums can stimulate resin formation as well as provide protection from pests and fungus.

Don’t Cheap Out on Your LED

LED grow lights do cost more than their older incandescent replacements up front. You must invest about 25% more money up front with LED over traditional bulb setups but the energy savings, as well as the usable lifetime of 50,000 hours, makes it a very wise decision. You’ll more than make your money back in savings with an LED.

Get the best product that you can afford the first time, the better the unit you buy the longer you’ll be able to use it to grow cannabis. You can always add more LED units to your setup in the future.

Now that you have a foundation on LED grow lights check out this review of the best LED grow lights on the market.