Dr Bruce Bugbee on light spectrum, infrared and plant growth / morphology (March '19)

[SuperBadGrower]

You just gotta see this:

https://kaltura.uga.edu/media/t/1_0...-lbzgWq7CA81S7advXTqTkLKCTC8DkLSFlb2xhZ_dwAUI

The work of Dr Bruce Bugbee and his associates is so valuable for indoor growing. New experimental data about IR, spectrum, shade avoidance/tolerance. It's hard to summarize but if you are into nerding out about lights and spectrum you will certainly enjoy this.

 

[SuperBadGrower]

Not cannabis specific. Some timestamps:

0:00 introduction

8:44 lighting history until now
21:57 experiments under different types of lights (red/blue, white, IR)

26:16 green light
30:16 light efficacy

32:26 experiments cont.

36:35 re-examining the definition of photosynthetic photons, emerson enhancement effect
45:55 morphological effects of IR, shade avoidance/tolerance

50:35 spectral quality vs quantity, purple, secondary metabolites

55:20 end

 

[Douglas.Curtis]

Ty so much listening now, wish I'd skipped to 8:44 lol

Yeah, their research is for "plant matter," so they approached it from a food perspective. There are still juicy bits in there. Amazing to see the changes between 2014 and 2018 in LED tech. Veg efficiency is off the charts with the best high tech blurple setups. Even white LEDs for flowering are outpacing HPS now. Impressive efficacy.

 

[Douglas.Curtis]

Seriously glad I ordered my custom LED without far-red. I'll be adding a far red chip in one corner, so I can do my own research and see what I like personally. The Mars Hydro TS series I picked up seemed to do just fine, but I'm not sure it has far red.

I'd like to see the nutritional density of the max output plants. They looked 'stretched' and not nutrient dense. I can see why it would be a seller with many crop growers, the visual differences are mostly impressive.

 

[SuperBadGrower]

Glad you also enjoyed this video Douglas! Like you said there sure is a lot of things that would be so interesting to find out about. Thanks to weed becoming legal we might get a chance to learn many interesting things about it. It's a great idea to do your own test with the far red. I haven't really seen a good side-by-side of it anywhere

I don't really remember them exactly, but I have read some papers about light quality (spectrum) experiments where the plant may turn out bigger but doesn't weigh more- or maybe the leaves get bigger but net photosynthesis is still the same as the smaller leaf plant (usually the ones getting more blue light). Looks can certainly be deceiving

But nobody needs to read a paper for that haha. Just go to the supermarket. So much great-looking things with bad taste, like you said/implied

 

[f-e]

That doesn't make far red light look very useful for us. Except as a mechanism for speeding flowering along. Which like other mechanisms, I find likely to reduce yield. Our plant is simply being rushed to complete.

However, with the sun or hid's as our base line, LED's are lacking far red. So reduced stretching is expected, as far red linked shade response won't exist.

Viewed as simply a survival mechanism, it could be advantageous to not have the far red. Plants trained into position won't spend so much energy trying to undo your efforts.

Just over 10% of the leds in my main lights are epistar 660, but I have no idea how efficient they are beside the other 90% which are lm301's. The growth isn't that of the sun or hid's though. It's much closer to my citizen cobs. Which I imagine some spectral graphs would show us. My 10% 660 being a joke beside what the sun puts out, which is almost a flat line straight past 730. Making 10% 660 a token gesture.

 

[Douglas.Curtis]

I think it may be useful in growing "Shade Grown" type cannabis in full light. I like a dense flower, but not too dense. Eventually I'll find out what I like for flowering response, as far as ripening and flower formation are concerned.

As it turns out, both the Mars Hydro TSW-2000 I have, and the custom light I ordered from Origlite/OriGulm (origlite.com), are both without far-red chips. This means 2 test platforms with slightly different spectrums.