Minimum lighting requirements

[BackyardBonsai]

Wow... some deep thoughts and knowledge there. You guys must really love your trees!

 

[eb84327]

Thanks guys. This has been a very helpful. Very informative, exactly what I was after!!

Edit:. I love a good scientific discussion. B.N. is an awesome site and so are the members!

 

[Tbone5660]

Would (1) Single 2ft T5 6400k HO light with reflector be enough for (1) BRT 15" tall placed at a Western facing window or should I go for a (2) bulb setup?

https://www.amazon.com/gp/product/B00AKKUBDQ/ref=ox_sc_act_title_1?smid=ATVPDKIKX0DER&psc=1

 

[leatherback]

So I live close to the Washington borderline. All the dope growing outfits, commercial, are switching to LED. So they have found something that's working. Curious

Yeah, my alma mater, Wageningen UR, did a large project in starting 2014 assisting professional greenhouse growers in setting this up. As you know, the Netherlands is 2nd largest producer of plants / fruits / vegetables in the world. Mostly due to huge greenhouses in the west.

https://www.wur.nl/nl/nieuws/Met-ledverlichting-energieverbruik-glastuinbouw-halveren.htm
https://www.wur.nl/en/newsarticle/S...-reduce-energy-consumption-in-greenhouses.htm

https://www.nationalgeographic.com/magazine/2017/09/holland-agriculture-sustainable-farming/

More: https://www.wur.nl/web/show/search?...d=26098&searchid=94196&keyword=greenhouse+LED

 

[TrunkTickler]

Correction
Generally and In terms of PAR:
30 µE m−2s−1 minimum
30 - 60 µE m−2s−1 shade tolerant trees
60 - 90 µE m−2s−1 medium light
> 90 µE m−2s−1 high light requirement trees

I think you may be off by a factor of 10. uE = umol right? From what I've read 1000 PAR (ppfd, umol/m^2•s) is the upper limit.

If someone could tell me where this rationale comes from I would appreciate it, I've been looking into this quite a bit. From what I've read (which is mostly bassed on cannabis research) is that above 1000 PAR the plant becomes carb limited and not light limited so supplemental CO2 is required to further increase growth.

This doesn't make sense to me because high light plants would be used to full sunlight, especially tropicals around the equator, these light levels would far exceed 1000 PAR, while the CO2 levels would be relatively the same, maybe higher indoor actually.

Cheers,
Connor

 

[Gustavo Martins]

I think you may be off by a factor of 10. uE = umol right? From what I've read 1000 PAR (ppfd, umol/m^2•s) is the upper limit.

If someone could tell me where this rationale comes from I would appreciate it, I've been looking into this quite a bit. From what I've read (which is mostly bassed on cannabis research) is that above 1000 PAR the plant becomes carb limited and not light limited so supplemental CO2 is required to further increase growth.

This doesn't make sense to me because high light plants would be used to full sunlight, especially tropicals around the equator, these light levels would far exceed 1000 PAR, while the CO2 levels would be relatively the same, maybe higher indoor actually.

Cheers,
Connor

i don’t see any contradiction. I’m talking about minimum light requirements. You’re talking about maximum light requirements. I said that sun-loving plants need greater than 90.

Too much light causes photoimibition. Plants shut down and make no photosynthesis

 

[ysrgrathe]

i don’t see any contradiction. I’m talking about minimum light requirements. You’re talking about maximum light requirements. I said that sun-loving plants need greater than 90.

Too much light causes photoimibition. Plants shut down and make no photosynthesis

Yes, well, it is true that 1000 is more than 90 but I think many trees likely have a much higher minimum than 90. 100 par is what I use for seedlings and cuttings! ("Low" intensity)

The following are DLIs for a few plants. Any "full sun" tree (e.g. pines) likely requires similar light to tomatoes. 30 dli is closer to 600 umol for 16 hours.

DLI requirements for common crops
Lettuce, Pepper 12
Basil 30
tomato, seedling 5-6
Tomato, production 30

 

[eryk2kartman]

Here is a good video about indoor lights for bonsai.
He goes through everything.

 

[TrunkTickler]

i don’t see any contradiction. I’m talking about minimum light requirements. You’re talking about maximum light requirements. I said that sun-loving plants need greater than 90.

Too much light causes photoimibition. Plants shut down and make no photosynthesis

100 par is nothing lol that's what the max is for tissue culture, that's to low for low light plants.

 

[TrunkTickler]

Here is a good video about indoor lights for bonsai.
He goes through everything.

Lol that's me! Some mistakes in that presentation

 

[Gustavo Martins]

100 par is nothing lol that's what the max is for tissue culture, that's to low for low light plants.

Abstract: Information on the dynamics of sapling growth of Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco) and lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm), two dominant species in the interior of British Columbia, Canada, is incomplete and thus the objective of this study was to understand how light availability and sapling size interact to influence their growth and crown morphology. In an undisturbed forest, 360 saplings were randomly selected in three light classes 0–15, 15–30, and >30% PPFD (photosynthetic photon flux density). A number of morphological and growth parameters were measured, including height and lateral branch growth. Douglas-fir had a more plastic crown morphology than lodgepole pine with its leader to lateral branch growth ratio, live crown depth, and number of branches increasing with increasing light class. Sapling size had little effect on morphological characteristics, but larger saplings of both species had greater absolute height growth and lateral branch growth than did smaller saplings. Both Douglas-fir and lodgepole pine were able to survive up to 50 years and attain a height of 3 m at less than 5% PPFD. These results further suggest that shade tolerance is greater on drier sites, although the mechanisms for such increases in tolerance are unknown. The ecological implications of these findings are discussed in a forestry context.


I maintain stock cultures of macroalgae at around 3-5 par

 

[amcoffeegirl]

Here is my results growing ficus and Haworth is indoors for the last 2 years.
I used aquarium lights mounted under shelves. The shelves are approx 16 inches apart so the trees are about 8-10 inches from the lights. I use this as supplemental lighting because I am near a big double south facing window. I have the stingray lights by finnex.
But I have used the fudge ray and planted+ over aquariums.
If you got a light with the same power or measurements as the planted+ you would have great lighting for growing.
https://www.plantedtank.net/forums/145-finnex/189944-finnex-ray-ii-fugeray-par-data.html
These measurements are for underwater.
They may be higher outside of water. With LEDs and aquariums it is all about the par rating. These are great lights.

 

[TrunkTickler]

Abstract: Information on the dynamics of sapling growth of Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco) and lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm), two dominant species in the interior of British Columbia, Canada, is incomplete and thus the objective of this study was to understand how light availability and sapling size interact to influence their growth and crown morphology. In an undisturbed forest, 360 saplings were randomly selected in three light classes 0–15, 15–30, and >30% PPFD (photosynthetic photon flux density). A number of morphological and growth parameters were measured, including height and lateral branch growth. Douglas-fir had a more plastic crown morphology than lodgepole pine with its leader to lateral branch growth ratio, live crown depth, and number of branches increasing with increasing light class. Sapling size had little effect on morphological characteristics, but larger saplings of both species had greater absolute height growth and lateral branch growth than did smaller saplings. Both Douglas-fir and lodgepole pine were able to survive up to 50 years and attain a height of 3 m at less than 5% PPFD. These results further suggest that shade tolerance is greater on drier sites, although the mechanisms for such increases in tolerance are unknown. The ecological implications of these findings are discussed in a forestry context.


I maintain stock cultures of macroalgae at around 3-5 par

5% of what total? If you would give the source I would like to read this study. This doesn't prove your point at all, 3m in 50 years is abysmal growth rate for a Doug fir

Your original post said 'in general', 30 PPFD minimum for shade trees, only 6x the intensity of your algae (a far cry from a tree) that are mostly sustained by the sugar in the medium. Everything I've read says your off by 10X.

 

[Gustavo Martins]

5% of light reaching the apice.

http://www.nrcresearchpress.com/doi/abs/10.1139/x98-189

 

[Gustavo Martins]

Have you ever done PAR readings in a forest?

 

[ysrgrathe]

Gustavo I think we're talking past each other. Can some pines survive under low light? Yes. Is achieving 3m in 50 years healthy growth for bonsai? No.

 

[Gustavo Martins]

Gustavo I think we're talking past each other. Can some pines survive under low light? Yes. Is achieving 3m in 50 years healthy growth for bonsai? No.

True. But title of thread is ‘minimum light requirements’ and not optimum light. That’s what I’ve been trying to say.