Cannabis Lighting Myths and FAQs with Dr. Bruce Bugbee

[GMO]

Dr. Bruce Bugbee debunks myths and answers FAQs on grow lights for cannabis based on his research so far at Utah State University's Crop Physiology Lab (see time-stamps below to navigate topics). Bruce is a world-renowned crop physiology professor famous for his work in controlled environment agriculture for NASA and is president of Apogee Instruments, a developer of research-grade instruments used in precision agriculture. Bruce's lab at Utah State is one of the few with a license to study cannabis cultivation with several active research projects underway (see: https://www.usu.edu/today/?id=58336 ). The lab's license is to research hemp, but these principles apply to marijuana, including sativa and indica. Some of Bruce's answers in this video are based on what the research is showing so far, but further tests are underway. As this is a very hot topic right now, we will do our best to monitor questions posted in the comments below and ask Bruce to answer them in future videos.





Timestamps of topics covered:
0:00 Intro
2:24 Light as one of the nine cardinal parameters
4:04 Can too much light cause problems with my cannabis plants?
5:30 How far should my lights be above my cannabis plants?
9:30 What is the optimum light intensity for growing cannabis?
16:59 PAR and PPFD explained
19:30 The best DLI (Daily Light Integral) for Cannabis
24:25 The proper tools to measure light levels
26:40 DLI levels for seedlings/cuttings
27:20 Photo periods and light pollution thresholds during dark periods
30:20 New light pollution sensors
31:30 Light requirements of different cultivars
32:50 Light quality effect on the synthesis of cannabinoids and terpenes
34:17 UV and Far-red effects on cannabis
39:40 Optimal spectrum for veg and flowering
42:52 Design Light Consortium (DLC) and light efficiency listings

[Labs Dexter]

Great post I'm growing under cobs and allways had issues of bleaching and plants drying dead over night... could it mean I need more water into the feed to make things tick along well, so I'll aim for one day water one day feed once roots are established and into the flower room which is pretty bright :)
F buying one of those meters tho I'll go by how plants lives or die lmao

[GMO]

Great post I'm growing under cobs and allways had issues of bleaching and plants drying dead over night... could it mean I need more water into the feed to make things tick along well, so I'll aim for one day water one day feed once roots are established and into the flower room which is pretty bright :)
F buying one of those meters tho I'll go by how plants lives or die lmao

Coco should always be fed nutrients with every fertigation. No feed, water, feed routine in coco, thats more of a soil method tbh dude

Agreed about the meter. but the information given in the vid i think helps us workout the point where we need to start making adjustments to the environment

There is this thread that should help with how to approach adjusting your lights as appropriate to plant health getting-to-grips-with-par-ppfd-and-dli-4861

[Point 5]

Watched this last night. Really good info just need to process now

[GMO]

On this tonight.

Watched this last night. Really good info just need to process now

Hopefully this helps grasp the value of the info... getting-to-grips-with-par-ppfd-and-dli-4861

and im always happy to discuss further :D

[GMO]

i know you are! but then i don't get any work done in the day lol.

that said i now need to measure PPFD and work out my current DLI on both plants. I'd like to see how close i could get to 40, so now i need to buy a PPFD meter

in the thread i linked above there is a lux to ppfd calculator. maybe see if thats gonna work out cheaper for you?

also there are plant signs which will let you know when nearing light intensity which is too high