Most likely it’s the many myths, some started by the light manufacturers themselves, which have given LED grow lights such a bad reputation with indoor gardeners. It seems as if many LED lighting manufacturers don’t actually grow with their lights: their leadership team usually consists of a lighting engineer, plus an entrepreneur with an interest in gardening. Neither of them has much indoor gardening experience, if any. They’re chasing the next trend with the hope of turning a dollar, and with little practical gardening experience backing up their claims, they have inadvertently poisoned their market with misinformation.
To be fair, it’s not all of the LED guys, and it’s not just them. The indoor gardening industry itself has perpetuated these myths out of ignorance. It’s easy to believe “facts” about LED grow lights when the same message comes from multiple trustworthy sources, including the distributors and magazines that serve the hydroponics industry.
A common question about LED grow lights is “Are they ready for prime time?” That’s an easy question to answer: YES, because they have been for a while and they are just getting better and better. Many developments and trends make LED grow lights the right choice for indoor gardeners, now. These include improved emitters, secondary optics, increasing electric rates, reduced waste,and ease of use.
• Better Emitters
One of the biggest factors limiting the market potential for LED grow lights until recently was the availability of LED emitters that produce the correct spectra of light needed for needed for photosynthesis, particularly 660-nanometer (nm) emitters. “Nanometers” measure the energy in light and describe how big (how small, actually) the wavelength of light is at various points along the light spectrum. The 660nm emitter emits light in the far end of the red spectrum and is particularly important for photosynthesis. It’s amusing to see how many LED grow light manufacturers claim to be the first or only manufacturer to use “true 660nm emitters.” Before 660nm emitters were manufactured, LED grow lights definitely lacked the power and punch needed for good harvests. Now, a few years later, more powerful emitters in a wider range of colors have spawned a new generation of LED grow lights. These newer LED lights offer significantly improved spectrum and output strength compared to earlier generations.
• Secondary Optics
A second, huge area of improvement is the “secondary optics” being paired with LED emitters. These small plastic focusing lenses are positioned atop LED emitters to intensify the light and direct it downward and outward. Secondary optic lenses significantly improve the evenness of the light over the plants’ canopy and penetration deep into the plants. There is lots of research going into secondary optics, so expect to see more innovation here in the future.
• Increasing Electrical Rates
Higher electrical rates provide significant incentives to switch to LED grow lights now. In Southern California, our electrical provider SoCal Edison (SCE) has announced that electrical rates will rise every year for the next few years. A 1000-watt high-intensity discharge (HID) light running a 12-hour bloom cycle every day uses 4.3 megawatts of electricity in a year. At SCE’s current peak rate of $0.36 per kilowatt-hour, it costs more than $1,500 per year to run one 1000-watt grow light, and that
does not include the electricity to maintain the environment, such as air conditioning and ventilation fans. LED grow lights can cut that expenditure in half or more.
Ease of Use
Yet another reason for why “now” for LEDs is their consumer-friendly form factor. They are so easy to use: just hang them up and plug them into a timer. There’s no separate ballast to hook up or air ducting to connect, adjust, or worse fall off. There are no lamps to change when switching from vegetative to bloom stages, ever. Also gone are potentially hazardous situations that can arise when handling HID lamps: no burns from hot lamps, no chance to drop the lamp into your garden and damage either your plants or the lamp, and no worries about the lamp potentially exploding from contaminates not removed after handling or nutrient solution splashed up during watering or spraying.
•Hobbyist: LED grow lights as primary
•Small Commercial: HID primary, LEDs supplemental
•Commercial: LEDs as supplemental light in greenhouse
Wavelengths, in nm
•440-460 Dark Blue
•660 “Red 660”
•Beam Angle: Narrow or Wide
•Surface area size in square inches
•Exposed to the air?
•Type: Constant Current or Resistor
•What do they control?
•Emitter type: Single or Multiple emitters/single lens
•If multiple, wattage & how many?
Grow Light Wattage
•How are grow light watts computed? Wall watts or total of emitters?
•Individual light heads with multiple emitters
•Clusters or “rosettes” of emitters
•Yes or No
_____ Square footage of garden space being illuminated
_____ Micromoles of light your garden needs (daily light integral)
_____ Micromoles of light produced at recommended hanging height
_____ Manufacturer recommended coverage area
•Large company, large-scale importer or manufacturer
•Small company, small-scale importer or manufacturer
•Direct drop ship from foreign suppliers
•Homebuilt, hobby, or DIY