Reducing PPFD in late Flower

[pulpoinspace]

TLDR: I was wondering if any of you reduce PPFD late in flower?

Long version:
The reason I'm asking has a bit to do with DLI and intensity of sunlight plants receive outdoors, BUT much more to do with the fact that my lower buds are actually finishing before my tops. I have tried reducing nitrogen to no avail, my only assumption left is that excessive PPFD causes the plant to continue to throw white pistils and foxtail.

I've begun running 10/14 once the lowers look like they're starting to swell, and the tops have stopped throwing white pistils. I'm thinking also tapering down PPFD will help with all the buds finishing at the same time. But I don't want to reduce density, and therefore yield. Just wondering what's the best way to fix this. Obviouosly 10/14 and dimming both reduce DLI, not sure which more effectively solves my problem.

So, if anyone does this, or has experienced similar "problems" and solved it another way please let me know.

 

[SpawnOfVader]

What kind of lights? How big are the plants? LED lighting can't efficiently penetrate a deep canopy... so training would really come into play.

I'm planning on chopping just my top buds and letting the bottom ones finish out over an additional week this cycle. Selective defoliation has helped a ton with my lower buds not developing though.

 

[SpawnOfVader]

Edit: actually looked at your grow journal and you're doing everything I would have with those plants. I think you're just struggling against the nature of plants with apical dominance and the limitation of LED lighting (canopy depth).

 

[dubekoms]

On foxtail prone strains I like to raise the lights the last 2-3 weeks, it definitely helps prevent that. By the time they start foxtailing most of the bulking is done so I don't think it affects yield all that much.

 

[dubekoms]

Cutting the light hours probably has the same results, just gotta experiment and find the sweet spot.

 

[pulpoinspace]

Edit: actually looked at your grow journal and you're doing everything I would have with those plants. I think you're just struggling against the nature of plants with apical dominance and the limitation of LED lighting (canopy depth).

Thanks, yeah my bottom nugs are actually finishing up before my tops. Ive had this happen the past couple cycles. Pretty odd.

On foxtail prone strains I like to raise the lights the last 2-3 weeks, it definitely helps prevent that. By the time they start foxtailing most of the bulking is done so I don't think it affects yield all that much.

Thanks. Yeah this is kind of the response I'm suspecting. I'm not sure how much DLI matters in terms of yield the last week or so. On your page there. Assuming dimming, 10/14, and moving the lights futher away all would have a similar effect for now.

 

[HydroKid239]

What kind of lights? How big are the plants? LED lighting can't efficiently penetrate a deep canopy... so training would really come into play.

I'm planning on chopping just my top buds and letting the bottom ones finish out over an additional week this cycle. Selective defoliation has helped a ton with my lower buds not developing though.

They are having the opposite in ripeness. Bottom is finishing first. Maybe harvesting the bottom ripened buds and lower the intensity would prevent foxtailing.. I'm curious because My last crop foxtailed up top on me. I am sure it wasn't heat doing it, because my temps in late flower were down in the low 70's. I have picked up a few do's and don'ts to fine tune this go around to see what the issue may have been. (Experimenting my theories of course)

 

[pulpoinspace]

They are having the opposite in ripeness. Bottom is finishing first. Maybe harvesting the bottom ripened buds and lower the intensity would prevent foxtailing.. I'm curious because My last crop foxtailed up top on me. I am sure it wasn't heat doing it, because my temps in late flower were down in the low 70's. I have picked up a few do's and don'ts to fine tune this go around to see what the issue may have been. (Experimenting my theories of course)

Exactly. I don't have any heat issues either. And have ruled out nitrogren. Thats why i'm starting to think its just late flower DLI.

 

[lazaah]

There's no signs of bleaching or stress/curling? Excess light leads to oxidative stress, the photosynthetic organelles still recieve photons but the photosystems are unable to prevent or manage the formation of hydrogen peroxide within the cell.

I wonder if it is to do with the change in spectrum as its passed through the canopy? Far red travels further/deeper than blue. FR promotes flowering/ripening. See where I am going?

 

[lungbutter]

Yes that's something I've noticed that if the light is too intense then the tops will run and pistils still look white and unfinished whilst the mid and bottom nugs look done.

 

[SpawnOfVader]

They are having the opposite in ripeness. Bottom is finishing first. Maybe harvesting the bottom ripened buds and lower the intensity would prevent foxtailing.. I'm curious because My last crop foxtailed up top on me. I am sure it wasn't heat doing it, because my temps in late flower were down in the low 70's. I have picked up a few do's and don'ts to fine tune this go around to see what the issue may have been. (Experimenting my theories of course)

Lol yea when I read it high I was like "there's no way a bottom bud is ACTUALLY done before a top bud" and reversed it in my head.

I'd assume the trichs are actually ripening as usual and it's just aesthetic for the additional white hairs @pulpoinspace?