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Spectral Intensity Distribution For Common Grow Lights vs The Sun

The Physicist

Well-Known Member
Hi everyone,

I have not seen this anywhere so I figured I'd post my data. I measured the spectral intensity distribution of various grow light sources that many new growers use and compared it to sun light at noon in California. While I don't personally have a HPS/MH, that data has been around for over 40 years, google it. Note, spectrum measured with Ocean Optics HR2000+. By integrating the spectral intensity distribution with the measured Lux, one can calculate their exact PPFD/PAR. See the attached info below:


Sunlight:
1585353875249.png


T5 Tubes:
1585353439276.png


Full Spectrum Feit LED:
1585353494987.png


Cool CFL LED 100W Equivalent (Home Depot):
1585353559982.png

Optimized Side/Under Canopy Spectra:
1585353632770.png


Warm CFL LED equivalent 100W (Home Depot):
1585353700355.png


CMH 315W Phillips 3100k Spectra:
1585353802971.png
 

Pepperhead

Well-Known Member
Hi everyone,

I have not seen this anywhere so I figured I'd post my data. I measured the spectral intensity distribution of various grow light sources that many new growers use and compared it to sun light at noon in California. While I don't personally have a HPS/MH, that data has been around for over 40 years, google it. Note, spectrum measured with Ocean Optics HR2000+. By integrating the spectral intensity distribution with the measured Lux, one can calculate their exact PPFD/PAR. See the attached info below:


Sunlight:
1585353875249.png


T5 Tubes:
1585353439276.png


Full Spectrum Feit LED:
1585353494987.png


Cool CFL LED 100W Equivalent (Home Depot):
1585353559982.png

Optimized Side/Under Canopy Spectra:
1585353632770.png


Warm CFL LED equivalent 100W (Home Depot):
1585353700355.png


CMH 315W Phillips 3100k Spectra:
1585353802971.png
Thanks for the info
 

The Physicist

Well-Known Member
Thanks for the data - nicely done and appreciate the posts - you obviously have the equipment to collect this data - I'm envious :thanks:
No problem! Hope its helpful. To me its a nice to see what options there are for improving the grow. For example I didn’t actually think the warm LED CFL equivalents gave off so much NIR which helps the plants during flowering quite a bit. Learn something new everyday! :meatballs: :Namaste:
 

The Physicist

Well-Known Member
I’m going to be adding the very warm CFL LEDs and two UVA Bulbs in about a week to my flowering plants. Should boost both flower and thc and terpene density/growth so it will be interesting. Good luck! :Namaste: :blunt:
 

The Physicist

Well-Known Member
Another great paper from 2018:

The Effect of Light Spectrum on the Morphology and Cannabinoid Content of Cannabis sativa L.

 

The Physicist

Well-Known Member
I’m actually upgrading to the Hortilux CMH 315W. I’ll post the measured spectrum later tonight when the ladies wake up.

Turns out the Phillips Bulbs have a UV blocker, and the Hortilux does not. So the improved UVA from bulb switching is all I’ll need.
 

The Physicist

Well-Known Member
Hortilux 315W 4100k CMH Spectrum:

Note the energy in the UVA band is more than 3x the Phillips 3100k. The energy in the 700-850nm range is comparable. Overall the Hortilux is the clearly better option as it provides a broader more smooth natural sun light spectrum.
hortilux 315 cmh.JPG
 
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