How can I compare different grow lights?
Many people look for a single measurement or statistic that can be used to compare different types of grow lights. Many companies try to impress by giving single, impressive PAR / PPFD, lumen / lux, μmol/J efficiency, or other measurements, but this certainly does not tell the entire story.
Any of these light statistics can be manipulated to look more impressive, but alone they don't indicate how well the light will grow plants.
The best way to compare any grow lights is to perform a side-by-side test actually growing plants: only in this way can you see through marketing hype to the actual performance of the light. Black Dog LED offers a 90-day money back guarantee on any one of our lights to encourage everyone to try their own grow tests with our lights. There is nothing like seeing for yourself just how well they grow plants compared to other lights, but we appreciate that this is not always possible.
When comparing grow lights, there are many important things to consider:
- Ultraviolet (UV) light yields larger, higher-quality, healthier plants. It stimulates production of secondary metabolites such as pigmentation, flavonoids, THC and CBD.
- Far red / near-infrared light (NIR) maximizes photosynthetic efficiency due to the Emerson Effect.
- The total spectrum is important. Many LED grow lights claim to be "full spectrum" but use only a few discreet colors or white LEDs perfect for human eyes but inefficient for plants.
- Individual light colors must be present in the correct ratios. For example, too much far red / near-infrared light compared to red light, or too little blue light compared to red will cause plants to "stretch" and get leggy. This hormonal trigger is based purely on spectrum and not intensity- this is why plants under HPS lights grow long, leggy stems even with incredible light intensity.
- Using different spectrums for vegetative and flowering growth stresses plants and decreases quality. Lights that work for both vegetative and flowering also allow for greater flexibility.
- The intensity of the light- not just at a single point, but PFD over the entire growing footprint at the recommended hanging height.
- The efficiency of the grow light, measured using the entire fixture in terms of light actually delivered to your plants: those HID reflectors aren't as reflective as you might think.
- Some lights have supplemental side-lights for changing the spectrum that are supposed to be turned on daily for a period of time. Is it possible to do this with a timer, or will you have to remember to turn it on and off again every day?
- For LEDs in particular, the design of the light is critical as well:
- Passively cooled LED grow lights are less efficient than actively-cooled LED fixtures. While fans are a moving part that could break, we utilize a patent-pending redundant system of fans to ensure our LEDs are kept cool.
- Primary lenses increase efficiency by harvesting more light from the LED.
- Glass protective lenses steal 10% of light and reduce efficiency.
- Secondary lenses are usually used to focus the light only to give it impressive PAR / PPFD statistics over a small portion of the footprint. Focusing the light in this way doesn't grow plants well in the entire lighting footprint!
- When reflectors are used in LED grow lights it usually indicates the beam angle of the primary lens is not correct, or that the efficiency-enhancing primary lens is missing entirely.
Even considering all of these things, it isn't easy to compare grow lights based on statistics other than actual yield. Try one of our lights with our money-back guarantee and see how well they work!