Current and future grow journal


I’ve mentioned there before, is what it is. I did notice that ilgm advertises there.


I was thinking somewhere in the range of 30minutes .


Do you know why you would do 30 minutes?
From my research that’s way to long. You only need around 2000-4000umol to get the desired effect, which if using Cree diodes. Could be achieved fairly quick.
If you use it too long, it will cause unwanted stretching because of Shade avoidance Syndrome.

I will do the math for you for 10 of them and see how long u would need to run them, you’re in a tent or no?


So with 4x6 area that’s 24sqft which is 2.23 sqmeters.
The Cree XP-E are around 2.1 vf at 700mA according to spread sheet I am not entirely sure on their efficacy but lets do 45% ( im sure they are more)
So 2.1vf x .7A = 1.47w per x 10 = 14.7w x 45% = 6.615 Par watts.
QER of far red is typically ~5.5 - 6.0 so
6.615parW x 5.5 QER = 36.38 Umol/s which would be your PPF.
Your area is 2.23 sqmeters so 26.38 / 2.23 = 11.83 PPFD ( not factoring in wall loss)
You would need ~ 4000 Umols to trigger the phytochrome response ( maybe slightly less or more) so
4000 / 11.83 = 338 seconds or ~6 minutes.
Math might be off slightly due to certain variables. Such as QER and efficacy of the diode. But its around that area. Which sounds right cause im at 5.5 mins and my buddy Randomblame( in the thread) uses the Cree and has had good luck with them.

You can also choose to run them softer and increase time, but all you’re trying to do with far red is switch the phytochrome response, with using far red, you can then do 13.5 hr lighs on and 10.5 hr lights off and still continue to flower.


I’m interested in knowing the effect of the extra hour or so of light on time during flower? Does it make bigger buds or shorten flowering time? Or both maybe?


Usually faster finishing times are what is being reported, with the fastest times at 12.5 hours off, 11.5 on. The far red gives you around 1hr 45 mins to 2 hrs of extra time in your day really, so you can use that for more photosynthesis, or more time in the dark.
Personally I’m extremely new to it, so I must going off what I read.


Interesting stuff. I look forward to seeing more people try it here. I looked at that thread at the other place looks like a pretty long read so I’ll browse through it during quiet times here lol.


Its a very long read, and honestly I would start more towards the back 1/3 of the thread. It seems most of the stuff up front is trial and error, and a lot of it not even to do with Far Red (a lot of photo red and trying for the Emerson effect rather than End of Day treatment)


Thanks that’ll save me at least a week worth of reading lol


I was assuming 30. 15 before lights out 115 after. If 5.5 minutes is what math tells us 5.5it is. 6x6 room with 4x6 grow space. Mylar walls.
What driver would I want?
What happens if I leave it 12/12?


I have never done it so I don’t know. But I don’t know why you would want to. knowing what the effects of far red do. The only thing you are trying to do with the far red is switch the phytochrome response. Nothing else. So no reason to leave it on more than needed, especially when it can cause adverse effects that you don’t want. such as unwanted stretching.

If you want something to keep on during lights on that has all of that I would look into HLG QB 18 or the HLG 35. It has 6 630nm 8 660nm and 4 730nm diodes added.


As for the driver. If running them at 700mA I would go with the Mean Well LDD-700LS same as the RapidLED puck. It has a constant current voltage region of 2-28v so you would need 2 of them to power 10 stars (@ 2.1vf per star) I think they sell it as a step down driver, or for just regular hookup.
@dbrn32 might have a better suggestion to power them. I am not too familiar with Meanwells smaller drivers.


I meant eod at 5mjnutes. Leaving lights on at 12/12 not 13/11. What would that do. Sorry for not being clear.


Ldd series is dc to dc right? So you’d need a separate power supply like an lrs to power it.


Which power supply then?


That’s right the LRS and Yea sorry @Newgrwr2018 I see what youre saying now. Yes you can leave your lights 12/12 and it will do what you need it to.


@dbrn32 would he not be able to power it off one of the drivers he already has?


How’s would I time that?


The individual control would probably be bigger hassle than it’s worth to do that, and would be assuming there is enough headroom available on current driver too.

@Newgrwr2018 if you get me a count of which specific leds you want to use I can look for a driver.


10 of these