So by logic i would need more ppfd in less light hours.
Max PPF/PPFD with and without Co2
- Thread starter Smoke-A-Cola
- Start date
Icemud420
Well-Known Member
Yes, figure out your target DLI and then calculate the PPFD from that, based on how many daylight hours.
Actually by going 24/0 i will shorten my veg time. But dont plants need some night??
wietefras
Well-Known Member
They are fine without night. The thing is though, you will see diminishing returns. The plants can process the light more efficiently when they get some rest. So when you light them for 18 hours they will use the given light more efficiently then when you spread out the same DLI over 24 hours and keep them going all day.
It works fine though. Several people even do whole grows with auto flowers on 24/0.
There are my 4 bag seed plants on 18/6.
Beggining of the 9th day. Oh and i make sure to put them almost full dry before watering now. I use my lux meter and i have my conversion factor 0.0292. Seller sent me a light test and i simply: PPFD/LUX=FACTOR
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master420ofkush
Member
45 dli is max without co2. works for me. top of canopy receiving approx 1000-1050 ppfd. edges of canopy around 650-750.
you can achieve same results with different lights on times with autos. for example- i run autos in vegging tent at 18/6, i try to keep the max ppfd at top of canopy around 600-650 which roughly translates to 38-42 DLI.
personally i try to keep the dli a little bit lower if i am using higher hours of light as opposed to 12/12. so that means, im comfortable pushing the DLI limit on 12/12 as close to 45 as possible, but at 18/6 i try to max out at 40 instead.
have gotten excellent results with both methods, if you cant understand this, i dont know what else to say
you can achieve same results with different lights on times with autos. for example- i run autos in vegging tent at 18/6, i try to keep the max ppfd at top of canopy around 600-650 which roughly translates to 38-42 DLI.
personally i try to keep the dli a little bit lower if i am using higher hours of light as opposed to 12/12. so that means, im comfortable pushing the DLI limit on 12/12 as close to 45 as possible, but at 18/6 i try to max out at 40 instead.
have gotten excellent results with both methods, if you cant understand this, i dont know what else to say
It would have been nice to see them take the same measurements in flowering plants. In my opinion that is the biggest flaw of this paper, its a mistake to assume the numbers stay the same the whole grow.
plumsmooth
Well-Known Member
I was hoping to see (I haven't finished the thread yet!)
Someone talk about and take into account the issue with a plant -- even one trained LST -- has plat tops and colas and side branches at different height.
Therefore even if the plant can not use the full 1400 PPFD at 12 Inches I am getting with my 315 CMH at the top of the plant -- is it not better to have it as high as possible (as long as not bleaching) at the top so the lower branches meet the minimum requirement?
Someone talk about and take into account the issue with a plant -- even one trained LST -- has plat tops and colas and side branches at different height.
Therefore even if the plant can not use the full 1400 PPFD at 12 Inches I am getting with my 315 CMH at the top of the plant -- is it not better to have it as high as possible (as long as not bleaching) at the top so the lower branches meet the minimum requirement?
plumsmooth
Well-Known Member
When it says 510 Minimum, does that mean at the top, at the middle, bottom etc>??
This is the part I am confused by. I suppose the highest point of the plant (assuming not perfectly lst'd) should be no more than 1000 to avoid LED burn? Or could the highest point handle 1500, if it was only 2 or 3 colas that just happened to be 6 inches taller than the rest?
This is the part I am confused by. I suppose the highest point of the plant (assuming not perfectly lst'd) should be no more than 1000 to avoid LED burn? Or could the highest point handle 1500, if it was only 2 or 3 colas that just happened to be 6 inches taller than the rest?
plumsmooth
Well-Known Member
I am struggling to figure out the ideal hanging height of my Scorpion Diablo. Originally when I got it I was confused then I got Photone Par Light Meter for Iphone. At this time I decided since the measurement was identical to my 315 CMH at 15 inches, that that would be fine.
However I only just encountered the "cumulative" measurement which is based on light cycle and total hours illuminated! This further confuses me and makes me think just because one of my large plants could take 2 315's CMH at 15 inches doesn't mean it will take the 6 Diablo boards of the Scorpion -- each of which -- seems equivalent to a 315 CMH at only 100 WATTS!
So based on my PPFD measurements the Scorpion Diablo 650 Watt is equivalent to 6 315 CMH's! So if this is 3x the Light of 2 315 CMH's then maybe 15 inches is too close now wihtout CO2....
Furthermore, aside from accumulative Daytime Daylight hours, I am thinking there must be an overall canopy cumulative measurement as well? All I know is it seemed I got a better yield on my first run whereby I had the thing at almost 3 feet for the first half of flowering then came down to just above 2 feel (without CO2)...
However when I measure full intensity at 15 inches it seems at an acceptable 1100 PPFD or so right at the top? But maybe 800-900 is just fine. But I like the idea of the penetration getting down a full foot and still baing at 500-600!
However I only just encountered the "cumulative" measurement which is based on light cycle and total hours illuminated! This further confuses me and makes me think just because one of my large plants could take 2 315's CMH at 15 inches doesn't mean it will take the 6 Diablo boards of the Scorpion -- each of which -- seems equivalent to a 315 CMH at only 100 WATTS!
So based on my PPFD measurements the Scorpion Diablo 650 Watt is equivalent to 6 315 CMH's! So if this is 3x the Light of 2 315 CMH's then maybe 15 inches is too close now wihtout CO2....
Furthermore, aside from accumulative Daytime Daylight hours, I am thinking there must be an overall canopy cumulative measurement as well? All I know is it seemed I got a better yield on my first run whereby I had the thing at almost 3 feet for the first half of flowering then came down to just above 2 feel (without CO2)...
However when I measure full intensity at 15 inches it seems at an acceptable 1100 PPFD or so right at the top? But maybe 800-900 is just fine. But I like the idea of the penetration getting down a full foot and still baing at 500-600!
plumsmooth
Well-Known Member
I do not see signs of light stress there! 800-1200 I guess that means your highest tops are topping out at 1200 PPFD? That is helpfull
sh0wtime
Well-Known Member
I'm at about 700 umol/s in my corners, about 950 for the rest of the field and up to 1100 on top of one of the plants that grew a bit taller.
I tried to push them too early tho (week2) and they surely didn't like it! As soon as I saw them goin brighter I lowered the intensity for another week.
Had to adapt my feeding also, they needed some cal/mag desperately wich comes with more nitrogen.
Now almost all my stems got down to a red-violet color, since I defoliated heavily. But as I said everything is superhealthy.
The 1100 umol/s region also shows no signs of stress at all.
I could actually push the lights even further a bit, but that's really alot of water and nutes they would be going through. I also wanna keep my temps at 27-28°C. Since I'm in 6 liter pots I think I'm good with where I'm at rn.
Cheers.
edit: pushed it a little to 29°C / 750/950/1150.
still no issues, leaves are getting a bit dry and I have to upp the nutes again.
Imma run this for 6 hours 3 hours in the morning a little less intensity and in the evenings as well.
co2 who?
I tried to push them too early tho (week2) and they surely didn't like it! As soon as I saw them goin brighter I lowered the intensity for another week.
Had to adapt my feeding also, they needed some cal/mag desperately wich comes with more nitrogen.
Now almost all my stems got down to a red-violet color, since I defoliated heavily. But as I said everything is superhealthy.
The 1100 umol/s region also shows no signs of stress at all.
I could actually push the lights even further a bit, but that's really alot of water and nutes they would be going through. I also wanna keep my temps at 27-28°C. Since I'm in 6 liter pots I think I'm good with where I'm at rn.
Cheers.
edit: pushed it a little to 29°C / 750/950/1150.
still no issues, leaves are getting a bit dry and I have to upp the nutes again.
Imma run this for 6 hours 3 hours in the morning a little less intensity and in the evenings as well.
co2 who?
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hello, i have run 1500 umols at the tops with no co2 with no visible displays. it won't hurt the plant.
but, i have found that for high quality with yield, and considering electrical efficiency, your target ppfd should be computed for 40-50 moles per diurnal cycle.
1150 umols ppfd for 12 hours is 49.68 moles. i run this regularly without co2.
950 umols for 12 hrs is 41.04 moles.
i have recently done 3 grows with an eight-hour flowering photoperiod at 1500 umols for a total of 43.2 moles and had excellent results. again no co2.
the formula is; ppfd x number of hours x 3600 (number of seconds in an hour) divided by 1000000.
for practical purposes you can just forget the division and read the first 4 numbers.
here's a recent experimental grow still in progress. 20 days into flower at 1200 umols.
editing to say that this also applies to vegetative plants. they are perfectly capable of handling this level of light after you acclimate them after transplanting.
give them a week of slowly ramping light before full power.
this also depends on the photoperiod. 24/0 at 500 umols is 43.2 moles.
700 umols for 18 hours is 45.36 moles.
i have also, for electrical efficiency, vegged using a 6on/6off schedule. 6 on at 1000 umols is 21.6 moles. two periods per day is 43.2 again.
but, i have found that for high quality with yield, and considering electrical efficiency, your target ppfd should be computed for 40-50 moles per diurnal cycle.
1150 umols ppfd for 12 hours is 49.68 moles. i run this regularly without co2.
950 umols for 12 hrs is 41.04 moles.
i have recently done 3 grows with an eight-hour flowering photoperiod at 1500 umols for a total of 43.2 moles and had excellent results. again no co2.
the formula is; ppfd x number of hours x 3600 (number of seconds in an hour) divided by 1000000.
for practical purposes you can just forget the division and read the first 4 numbers.
here's a recent experimental grow still in progress. 20 days into flower at 1200 umols.
editing to say that this also applies to vegetative plants. they are perfectly capable of handling this level of light after you acclimate them after transplanting.
give them a week of slowly ramping light before full power.
this also depends on the photoperiod. 24/0 at 500 umols is 43.2 moles.
700 umols for 18 hours is 45.36 moles.
i have also, for electrical efficiency, vegged using a 6on/6off schedule. 6 on at 1000 umols is 21.6 moles. two periods per day is 43.2 again.
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Comparator
Well-Known Member
Yes & No. Yes dli is important, no that's not all. Ppfd is equally as important because if at any point the ppfd is to high for to long then you'll likely experience light stress.
Comparator
Well-Known Member
OK, that's based on that particular light & spectrum. If there's no mention of those two things then the study is very, vague and once again incomplete or biased to what they want you to believe. Kindve like Fhose getting unsuspecting growers to believe high ppfd growingvis the wayvto go in ordercto get them to buy 1000w , 3x3 dimension lights that mostvof us realized was a bad thing a long time ago. Things go full cirlce like bellbottons. Lol! Ive destroyed other lights in sbs's using a 36-40 dli over a 60 dli. There's such a thing as to much light. That doubles expedentially when the spd is lacking and overabundant in the wrong wavelengths. Which just about all of the so called HE lamps are.
sh0wtime
Well-Known Member
6 hours on 6 hours off twice be 12 hours of light per day.
Never heard of this before anyways, but you got me curious how's that working?
quite well! they won't flower under this regime. i use it by switching back and forth between two rooms.
i have also vegged using 8-4-8-4 for the 24-hour period. this has produced the fastest veg rate for me. the 8-hour intense period followed by 4 rest hours allows the plant to fully process the assimilate.
what veg time i use sometimes depends on circumstances like temps and air movement. right now i'm in an old 1940's farmhouse while i'm building a house down the road. it's cold outside and the insulation is poor. lots of air leaks.
so i'm running both rooms 24/7 to keep the heat up. of course, i drop the light flow down to about 500 umols for this long of a period.
sh0wtime
Well-Known Member
Intresting!
Plants goin to work, then taking a nap to recharge and then back to work again.
You can prolly stress the hell out of em this way, no?
