[Lysrgic]

Originally Posted by olekingkole

I use 4 Philips Greenpower 14 watt far red bulbs in a 12x12 room to trigger night cycles. This way I can flower with 13 hours of light/day. This shortens flowering time by roughly a week. I could probably push it to 13.5 hours/day. The only problem I've experienced is getting all timers sequenced properly. Digital timers make it easier. You have to be certain that the far red lights really come on for 10 minutes after lights out. If the plants don't go into flower quickly, you may have your timers mis-set. I also use 4 Agro-Max Pure UVB t5's for 1 1/2 hours/day in 6 15 minute intervals. These provide much more UVB than the reptile bulbs.

Sound pretty awesome man! When exactly are you turning USB? Middle of day?

I got myself 5 of the LZ1-10R300 740 nm. Do you think ghost will be enough or to maybe even to much for a 1.2X1.2 m??

I should turn them on for the entire 12 hours of light, and that another 10 before and after, right? Having a thought about using dimming (middle of the day is Max peak?)

[Lysrgic]

Originally Posted by Lysrgic

USB

UVB*

[olekingkole]

I don't know if 740 nm led's will work. Mine are 730 nm and that's the wavelength at which the plant responds. I set them to come on five minutes before lights out and run them for 10 minutes after lights out. That's all that's necessary to put the plants to sleep. I run the UVB tubes for 6 fifteen minute intervals during the middle of the daily light period. That seems to be enough. Too much UVB can damage the leaves and reduce yield. Some people run the reptile bulbs a full 12 hours a day. These bulbs are much weaker than the Agro-Max bulbs, so running them longer makes sense.

[Dion]

https://www.inda-gro.com/IG/sites/def...0Revisited.pdf

[olekingkole]

What is your point, Dion? How is the McCree Curve relevant to the phytochrome reaction?

[Dion]

Originally Posted by olekingkole

What is your point, Dion? How is the McCree Curve relevant to the phytochrome reaction?

that was not in responce to ur post mate more for general reference in regards to driving photosynthesis under leds

but seen as u ask




https://en.wikipedia.org/wiki/Phytochrome

this shows that 650-720 seems to be the nm resposible for the reaction dropping off right around where mmccrees curve does


so ur 730s would be better than 740 i reckon

where did u get 730/740nm from?

an interesting question(at least to me as someone would builds leds and can recreate almost any immaginale spectrum) is

how much IR and or UV should we be using (like a % of total light for each?)

[Lysrgic]

Originally Posted by Dion

how much IR and or UV should we be using (like a % of total light for each?)

Also very interested! Can you give us some numbers? Nm or wattage?

The leds that I got are: https://eu.mouser.com/Search/m_Produc...252bIvnKtds%3d

I think they peak at 735 nm. They have a nice spectrum (for a far red) according to their charts.

[Lysrgic]

Where I read about the 740 nm: https://www.420magazine.com/forums/g...rum-730nm.html

[jikko77]

check beta test team album.
there is a light absorption graph, its from the very begin to the very end of a full grow cycle.
it show how much % and what wave lenght are needed.

as i have understood the deal:
the max pick is on 735 nm, most led have a delta of +- 10nm (or at least i've read so), carefull when you pick a far red led.
in some of their post they have talked about how many watt are needed, can't remener the specific quote, but they were a low watt quantity. i guess is a kind of fixed % over the total light emitted.

on what led do you need: it depends on what led you use to cover the par section of the grow light. that's why i'd like to get a read with a spectrometer.

i.e.: according to cree d.s. a cxb 3070 90cri 3000°k has a 60% value on the 680 nm, according to this i'd pick a mono covering from 680 to 730 nm to get the red/far red covered. same deal on the other side, with blue and uv. even green and orange.

as far as i've noticed, and as far as cutter say, some cxb has a very little far red and uv output.

here some led sample from cutter:
xpe: https://www.cutter.com.au/proddetail.php?prod=cut2841
4x xpe: https://www.cutter.com.au/proddetail.php?prod=cut2202
2x xpe 660 and 730 nm: https://www.cutter.com.au/proddetail.php?prod=cut2857

[Dion]

Originally Posted by Lysrgic

Also very interested! Can you give us some numbers? Nm or wattage?

The leds that I got are: https://eu.mouser.com/Search/m_Produc...252bIvnKtds%3d

I think they peak at 735 nm. They have a nice spectrum (for a far red) according to their charts.

ouch! thats expensive, also the bin is not properly listed

BUT they look like solid leds