The team at GrowersHouse tested 300-400 Watt alternative lighting using our new spectroradiometer, a spectrometer with optics. This $3,000 light meter measures not only light intensity but also the intensity of every color wavelength or the entire spectrum from a tested light. It is much better than a lumen meter and even better than a PAR meter at telling you a whole story about a light’s spectrum and the intensity of a grow light. The data it provides is then equated into a spectral graph. You may be familiar with these types of graphs even if you haven't heard of a spectroradiometer because on the side of some HID bulb boxes, such as a high pressure sodium (HPS) or a metal halide (MH), you'll see a graph that has different colors and is actually a spectroradiometer reading the manufacturer has done and published on the box.
This test measures performance of six different lights from 300 to 400 watts, most of them are what we would call alternative lighting. These are comprised of LED's, ceramic metal halides and, for reference, a 400 Watt HPS. The lights tested were The LumiGrow Pro 325 LED, Black Dog 360-U LED Universal series, Fero LED 10 Spot from Spain, SunSystem LEC 315 Ceramic Metal Halide, Kind LED K3 L600, and again for reference the 400 Watt HID setup with a Hortilux 400W HPS and a Quantum 400W ballast and a YieldMaster 6 inch air cooled reflector from Sunlight Supply.
In addition to taking the spectroradiometer readings which give us that graph of the light spectrum, we also took a 4 x 4-foot footprint and put the lights 24 inches above that footprint. Each light is also measured in 3 x 3, 2 x 2, and a 1 x 1 footprint within it, and a center reading. We measured within 33 points inside that 4 x 4 to get a really good understanding what the intensity of the light is over that space. Results are posted for each light. We hung the lights at 24 inches, although some are recommended for a smaller space, such as 3 x 3. We wanted to include the 4 x 4 because some people are doing that and we just wanted to see what the intensity would be. For example Black Dog LED recommended hanging its light at 18 inches rather than 24, so you might get different readings by moving the light. We needed to hang the lights at identical heights for a valid comparison.
We also hooked up each light to a Kill-A-Watt Meter to read the wattage, amperage, voltage and hertz. Readings reflect power use at the wall, rather than what companies overtly state. We also with this information made our own ratio, which we call the PAR/Watt Ratio. The PAR/Watt ratio is the sum of what the PAR was with that 4 x 4 footprint, divided by the watts the light is pulling from the wall. With that ratio you can see relatively how efficient a light can be. Again, that doesn't tell the whole story; it’s presented as another way to digest all this information.
A quick analysis of this information indicates that these lights are really good for different things. The Black Dog LED had not so much intensity in the center, but it had really high PAR for the outer edges. It was a little more consistent than some of the other lights.
The Kind LED, a newer LED to the market, was very intense over the center. It performed very well with the wattage it was putting out but didn't have quite the consistency over the entire coverage area. And the 400W HPS, with the way its reflector is made, has good and consistent coverage. The Ceramic Metal Halide light also performs well, showing the highest intensity with a fairly consistent coverage area. The CMH light comes with a 3100k Ceramic MH bulb for flowering growth, but a 4200k Ceramic MH bulb is also available for vegetative growth. By taking the average of all the PAR over the 4 x 4 footprint, we try to give you a basis for really just how much intensity each light is putting out over that 4 x 4 area.
Read the information to help you purchase the best light for your needs. If you’re lighting a 2 x 2 space versus a 4 x 4, you might purchase a different light after studying our results. We hope this helps you reach a better, more informed decision for getting a new light for your setup. There is much more that can be done with this information; we tried to put it in a few different ways that make it easy to interpolate what’s going on under each light, but we included the raw data in a spreadsheet that you can download and use in any which way you choose, including posting it online, making graphs for other people you think could benefit, or just show the story of the graphs and the spectrum in a different way.
Have an idea for GrowersHouse test topic? Please write to us at staff @growershouse.com or call. We could even include other lights in this test as an addendum.
300-400W Alternative Lighting Test Results PDF
Alternative Lighting Test: PAR Data Excel File
Alternative Lighting Test: Spectral Data Excel File
Shop these Categories on our site now:
Shop for LEDs
Shop for Ceramic Metal Halide Lights