What causes foxtails

[Hdinkleman]

I use Bridgelux eb gen2 3500k. I have 9 24" the were running at 225w. About 85% 12 inches from the tops. Even the lower stuff was foxtailling.

what was the number of lights on hours?
need that to calculate DLI

 

[Mastrmasn]

12 on 12 off.

 

[Chris Scorpio]

All my Amnesia Haze foxtail, and not a light issue

I've had many genetics do it with plants right next to it, same light but different strain, same height, never foxtail

I'm on the Genetics side of the fence, but for sure can be induced by stress and lights

 

[Hdinkleman]

All my Amnesia Haze foxtail, and not a light issue

I've had many genetics do it with plants right next to it, same light but different strain, same height, never foxtail

I'm on the Genetics side of the fence, but for sure can be induced by stress and lights

actually youre the one who told me my quantum board only pulled 201 from the wall which may have been correct for you but using a dli/ppfd and now having an actual ppfd meter is not correct for my light.
i have a feeling youre probably light atressing your plants causing those foxtails, but what do i know.

anyways im going to keep on with this post.
if anyone else wants to comment please either present your ppfd/DLI or post your wattage, distance and lights off lights on so i can get an approx reading using the calculator.

thanks

 

[Hdinkleman]

12 on 12 off.

according to the calculator your ppfd is 900+ and your DLI is 39 which is almost close to the 40 threahhold for co2.
900 ppfd is too much in itself.

so looks like im on to something

 

[Chris Scorpio]

actually youre the one who told me my quantum board only pulled 201 from the wall

Do you have a wall meter that shows watts

Mine shows exactly what I based my my calcs on by bds...and the driver

Per my Quantum Par Meter
QB lights
11/13 schedule

970par at 8"
620par at 12"
Amnesia Haze

1200par at 5"
C99 X Blueberry

6 bds pulling 460w at the wall
Measured under 4 bd driver at 305w

 

[Hdinkleman]

Do you have a wall meter that shows watts

Mine shows exactly what I based my my calcs on by bds...and the driver

Per my Quantum Par Meter
QB lights
11/13 schedule

970par at 8"
620par at 12"
Amnesia Haze

1200par at 5"
C99 X Blueberry

6 bds pulling 460w at the wall
Measured under 4 bd driver at 305w

par isnt ppfd though
i dont have a kill o watt, but my ppfd readings are almost an exact match +- 20 ppfd when i used the wattage ppfd-dli calculator

970 par is not the same as 970 ppfd

also chris could be that different strains have different thresholds of DLI before foxtailing occurs.
depending on sativa(more light tolerant) or indica (less) genetics in the mess of hybridized cannabis we have all grown to know and love.

800ppfd is the relative max without co2 supplementation
40 is the relative max DLI without co2 supp

what i want to find out is what is the max DLI before foxtailing occurs in late flower when plants should be ripening not spending energy making more calyxes and pistils

 

[Hdinkleman]

could be that you have been reading PAR and not PPFD. two different things but similar.

PAR photosynthetic active radiation
PPFD photosynthetic photon flux density.

closely related but different. ppfd is how much PAR falls within a second.

could be you were mistaken this whole time with your readings.

also the manufacturer itself says
“ adjustable dimmer from 135-285 watts”

 

[Chris Scorpio]

I know what I'm reading...lol

Par is par..ppfd is ppfd

But I'm not trying to dive into worm hole...lol

And the watts are the watts

But I understand what your try, or hoping, to determine, but it's still a guestimate since every strain will react differently

 

[Chris Scorpio]

also the manufacturer itself says
“ adjustable dimmer from 135-285 watts”

My only statement originally was the driver limits or can limit the watts they describe

Get a watt meter for $20, why I got one

Also got the par meter to find the sweet spot on multiple QB bds, also works fantastic

 

[LiberalThinker]

I know what I'm reading...lol

Par is par..ppfd is ppfd

But I'm not trying to dive into worm hole...lol

And the watts are the watts

But I understand what your try, or hoping, to determine, but it's still a guestimate since every strain will react differently

Unless their LED watts.

 

[Chris Scorpio]

Unless their LED watts.

Ya mean fake LED watts

Lol

 

[NamTran]

what was your DLI, ppfd and when did the foxtails occur?

Somewhere around 18". I don't have a good mean to measure ppfd but it was from a 2xQB288 running at maximum. The foxtailing happened around week 7 of flowering

 

[No Pain]

what i want to find out is what is the max DLI before foxtailing occurs in late flower when plants should be ripening not spending energy making more calyxes and pistils

so you feel that foxtailing is the plant deciding it needs to flower more and delays the ripening due to that ?

in regards to new pistils/calyxes late in flower I have always had strains go through a burst of new calyx's / flowers later in flowering ...sometimes its even followed by or proceeds a banana or 2 ...its the plants last ditch effort to trying to get fertilized .

 

[Hdinkleman]

Somewhere around 18". I don't have a good mean to measure ppfd but it was from a 2xQB288 running at maximum. The foxtailing happened around week 7 of flowering

same here, coincedence?
i think not.

 

[Hdinkleman]

so you feel that foxtailing is the plant deciding it needs to flower more and delays the ripening due to that ?

in regards to new pistils/calyxes late in flower I have always had strains go through a burst of new calyx's / flowers later in flowering ...sometimes its even followed by or proceeds a banana or 2 ...its the plants last ditch effort to trying to get fertilized .

yes i do think that

 

[No Pain]

yes i do think that

okay I am all for people doing studies in search of an answer to a question that makes their heart go pitter pater . Now for your study and data collection I would like to make a request … That request is that when you have two plants of the same strain( photoperiod strain that is ) that start to foxtail ..take one and put it under 10 hours of light and 14 hours of darkness a 10/14 schedule and leave the other under a 12/12 cycle . I feel that you will find that the one under the 10/14 schedule ripens a lot faster than the one under the 12/12 regardless of the amount of foxtailing .

 

[Hdinkleman]

This isnt as much about ripening the flowers as it is about whether your light is too strong/close. i had dropped my hours to 11 on 13 off on last grow and it was still foxtailing.
i would assume because the the high dli regardless of hours on

the amount of light per second squared/hours of light period=DLI

the plant in my tent is an auto. it is now receiving 11.5 hours of light. i have now dropped DLI to 19 at the highest cola and will keep it there.
i didnt notice any foxtail growth yesterday at 23 DLI.
still waiting for amber trichomes. mostly cloudy with some clear. been this way since the buds started to foxtail

 

[Barney86]

Some are caused by genetics, some strains are predisposed to it.
Most are caused by to much heat though.

Yup, exactly what I was gonna say.