Maximum safe PAR???

[Loc Dog]

I am running Vero 29 Gen 7's at 110 watts and getting foxtailing at 2 feet and around 750 PAR. I thought under 1000 was supposed to be safe. Any suggestions of safe PAR level at tops of buds to avoid problems? I did not get any light bleaching setup that way, while I did last time at one foot, and did not have PAR meter. Strain is GG4.

TIA

 

[f-e]

With everything else in place, 1500umol has been seen to work on the variety they had. That was co2 and everything.
My critical kush is the most resistant of the 5 I have. It will take over 1000 without co2 and shows no sign of hiding from it. No slowing I can see. It can hit the lights before it complains.
My cookies kush is a food hog that doesn't like a lot of light. Its hard to keep happy. 750umol will give it a flat top that foxtails sideways. Really quite odd.
600umol keeps everything I have happy. So there is quite a range to what mine like

 

[Loc Dog]

With everything else in place, 1500umol has been seen to work on the variety they had. That was co2 and everything.
My critical kush is the most resistant of the 5 I have. It will take over 1000 without co2 and shows no sign of hiding from it. No slowing I can see. It can hit the lights before it complains.
My cookies kush is a food hog that doesn't like a lot of light. Its hard to keep happy. 750umol will give it a flat top that foxtails sideways. Really quite odd.
600umol keeps everything I have happy. So there is quite a range to what mine like

Thank You!!! I will try 600 for rest of this grow, and all of next. Probably see a big drop in electric use too. The high light seems to cut down on heavy leaf on buds, but also not as pretty as they should be. Really wonder what it does to THC levels.

GG4 is a lite feeder. Only feed 600 - 650 PPM. No CO2. I am low budget grower.

 

[f-e]

I'm sat here, yet again, wondering it I should pot up my Cookies Kush or loose it.
Many of my plants are now fast versions, or selected for their speed. Perhaps this lowers the lighting requirement, as the fast genes are from low light areas of the globe.
I can only speak for what I have. 600umol can only feed so much of the genetic potential. Where pushed for answers, professionals have said it can provide 75% of the growth you might see with 1500umol and co2. Some charts indicate 800umol as the most you can apply without co2 limitations. With your 750 you are right up there, and would need suitable genetics and good air circulation. 400-800umol is the flowering window. In one book, at least.

 

[Sunshineinabag]

With everything else in place, 1500umol has been seen to work on the variety they had. That was co2 and everything.
My critical kush is the most resistant of the 5 I have. It will take over 1000 without co2 and shows no sign of hiding from it. No slowing I can see. It can hit the lights before it complains.
My cookies kush is a food hog that doesn't like a lot of light. Its hard to keep happy. 750umol will give it a flat top that foxtails sideways. Really quite odd.
600umol keeps everything I have happy. So there is quite a range to what mine like

Mg man

 

[Sunshineinabag]

Here check this out......


Great minds are always expanding

 

[Loc Dog]

Will try the 600 next run, then 600 one end and 700 the other. Just one small tent, so CO2 not practical. Trying to optimize cost to output. Just added 15 minutes, start and end of day IR light.

Wound up being coir runoff 2 to 3 times too high and PH one full number low. The PAR was 450 to 650 with tent open, so that was not the problem.

 

[Koondense]

Foxtailing can be related to high temps.
I have the same lights @95W and have no real issues, happens only to some varieties and some phenos, depending on the season and other factors.
Anyway 600 par seems a good level, probably offers the best gpw.

Cheers

 

[Mars Hydro Led]

With everything else in place, 1500umol has been seen to work on the variety they had. That was co2 and everything.
My critical kush is the most resistant of the 5 I have. It will take over 1000 without co2 and shows no sign of hiding from it. No slowing I can see. It can hit the lights before it complains.
My cookies kush is a food hog that doesn't like a lot of light. Its hard to keep happy. 750umol will give it a flat top that foxtails sideways. Really quite odd.
600umol keeps everything I have happy. So there is quite a range to what mine like

Will 1500 umol be too high for cannabis? Just curious.

 

[f-e]

Will 1500 umol be too high for cannabis? Just curious.

There is no return from adding more. 1500 is plateauing. With the plant employing protection methods to ensure it's not compromised by higher growth rates. This is almost theoretical though, seen by extrapolating from the data gained from lower light tests. Tests in the real world, where there is commercial use (funding)

 

[flylowgethigh]

Foxtailing can be related to high temps.
I have the same lights @95W and have no real issues, happens only to some varieties and some phenos, depending on the season and other factors.
Anyway 600 par seems a good level, probably offers the best gpw.

Cheers

Agree. Under MY lights (E680), 560-725 umoles at the tops seem to keep them happiest. That is 70-75% power at 14-24" above the peaks. My ambient CO2 is 600-700.

Any "hotter" and I think the light screws up the trics, but maybe also direct air from the fans.

 

[f-e]

I just went from 600 to about 850 and they they are. The explosive growths. Not so present if I run 850 from the start. Still there though, on the strains that do it the most. While others have not done it, and like the higher light.

I think diet is the key to controlling this. I suspect they take on more food, but as co2 intake becomes the limit, Some elements of the food become unbalanced. I'm musing over the idea Coco growers seem to hit the wall sooner. Which points to the K/Ca/Mg area. I'm looking at Mg in particular. I always have Mg issues and think coco's K excesses and LED's Ca needs might be leaving it out in the cold. An Mg foliar recently saw a burst of growth, much like the extra light bought. Both could be bringing extra P to the table. Mg through it's liking of P and the light causing a greater feed uptake that might not get used without the co2 and Mg. I have seen Mg from almost every angle, but struggle to get enough in there with the K and Ca of coco and led. As the 3 as a group can only reach a certain EC.
I'm in tiny pots. In bigger ones I barely see Mg as an issue. Bigger to me, is still small. About 8L of coco, 4 per meter. So 32L of coco per meter. Tiny is 8 1L pots per meter. So I do see problems pretty quick

 

[Mars Hydro Led]

There is no return from adding more. 1500 is plateauing. With the plant employing protection methods to ensure it's not compromised by higher growth rates. This is almost theoretical though, seen by extrapolating from the data gained from lower light tests. Tests in the real world, where there is commercial use (funding)

So cannabis cannot take more than 1500 umol even though using some CO2...

 

[Switcher56]

So cannabis cannot take more than 1500 umol even though using some CO2...

Ummm, for a "lighting company" one would think you (the company) would/should know the/that data?

 

[f-e]

I think of Mars as a well read manufacturing company.

I'm pretty sure 1500 is from a Bugbee youtube. As a professor he gets funding to look at the stuff we are interested in. Growing under lights just became legitimate business. So a lot of in depth projects are looking at cannabis. I think it was with optimum co2, which sticks in my mind around 800ppm. Not extremely high. But inline with the lighting increase.

Being so new, the papers are mostly on University websites.

I'm actually excited at the moment. I know it's the blooming season in Northern regions. Soon we will have this years results coming in for farming amendments. With greenhouse hydro results just weeks later. More proper decent sized studies to assimilate. These are exciting times. It rained today.

 

[Mars Hydro Led]

I think of Mars as a well read manufacturing company.

I'm pretty sure 1500 is from a Bugbee youtube. As a professor he gets funding to look at the stuff we are interested in. Growing under lights just became legitimate business. So a lot of in depth projects are looking at cannabis. I think it was with optimum co2, which sticks in my mind around 800ppm. Not extremely high. But inline with the lighting increase.

Being so new, the papers are mostly on University websites.

I'm actually excited at the moment. I know it's the blooming season in Northern regions. Soon we will have this years results coming in for farming amendments. With greenhouse hydro results just weeks later. More proper decent sized studies to assimilate. These are exciting times. It rained today.

Yes, we learnt a lot from professor bruce bugbee.

 

[Sunshineinabag]

Petrichor......inhale it when ya can

 

[Frosty Nuggets]

Remember, if you Bugbee you get stung.

 

[flylowgethigh]

Is the PAR we want dependent on the growth cycle? I have a problem with my tric heads disappearing, as if they were deflated balloons. The brown heads are not in yet, and then as I wait for that to happen the very tops just deflate. I am thinking that turning down the lights the last week or two may help reduce the loss of the goodies. Can the LED light burn up the juices? Is this a red / white /blue spectrum deal?

I also make sure the fans are not hitting right the tops too.

 

[Loc Dog]

Is the PAR we want dependent on the growth cycle? I have a problem with my tric heads disappearing, as if they were deflated balloons. The brown heads are not in yet, and then as I wait for that to happen the very tops just deflate. I am thinking that turning down the lights the last week or two may help reduce the loss of the goodies. Can the LED light burn up the juices? Is this a red / white /blue spectrum deal?

I also make sure the fans are not hitting right the tops too.

I am also interested and was going to post similar question. I was going to run an additional week, but it is so pitiful, does not seem worth it. Starting flushing for 3 days now, and was wondering if I should turn the lights way down. Feel like this grow was complete waste of electric.

Was also wondering about removing any big top leaves, to give light to shaded buds for last few days. Planning on removing the rest of large fan leaves when i turn off lights and let sit for 3 days before chopping up and hanging.