Foxtailing at the end of flower

is foxtailing normal at the end of flower? is it it's last push to produce bud? I'm talking dense buds but with little tiny foxtails on the tips of the buds that have randomly showed up week 8 into flower. or is it related to my temps being 28-29c?

What ppfd you think youre giving them? How close is light and how many watts? What kind of light? Some strains can do it easily but its not a great thing. People like it as it means extra bud but facts are facts, its a stressed response. Yes to make seeds rodelization from what I understand.

Its not really a indica thing though. I think my clone foxtailed a little bit or its just the light and how it grows but this bud or two this run had it really bad. I once had it rediculously bad and made me think I had a auto that needed 20 weeks to flower. They can keep going so if the rest is done you can just chop.

If developed enough you really cant tell the white hairs were there most the time.

84F isnt bad but coupled with leds too bright and close can do it. I havent seen foxtails in a while, this bud here is the closest I seen and its not really foxtailing since it finished without dimming the light or anything and doesnt go too far.

medidedicated said:

What ppfd you think youre giving them? How close is light and how many watts? What kind of light? Some strains can do it easily but its not a great thing. People like it as it means extra bud but facts are facts, its a stressed response. Yes to make seeds rodelization from what I understand.

Its not really a indica thing though. I think my clone foxtailed a little bit or its just the light and how it grows but this bud or two this run had it really bad. I once had it rediculously bad and made me think I had a auto that needed 20 weeks to flower. They can keep going so if the rest is done you can just chop.

If developed enough you really cant tell the white hairs were there most the time.

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I'm not sure what ppfd I am giving them bro, the light I am using is a Lumatek LED light on 100% and they have been fine on 100% for the last 6 weeks with no signs of foxtailing. They have been the same distance from the plants for the last 6 weeks with no signs of foxtailing. the light is 465watts. The light is about 15 - 20 inches away or something like that. I'm thinking it's because it's 29c in the tent maybe? it's defo not the distance of the light because the light distance has been the same distance for the last 6 weeks and I haven't changed anything. But I am slightly struggling with the temps tho. it's getting up to 29c sometimes.

Check out these foxtails I once had. Look like fingers.

medidedicated said:

Check out these foxtails I once had. Look like fingers.

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Oh shit yeah, that's wild lol. Mine aren't that bad. Mine are just tiny little foxtails on the tips of the buds that are about 1cm in length

Fish scale said:

I'm not sure what ppfd I am giving them bro, the light I am using a LED light on 100% and they have been fine on 100% for the last 6 weeks with no signs of foxtailing. They have been the same distance for the last 6 weeks with no signs of foxtailing. the light is 465watts. The light is about 15 - 20 inches away or something like that. I'm thinking it's because it's 29c in the tent maybe? it's defo not the distance of the light because they have been fine for the last 6 weeks and I haven't changed anything. But I am slightly struggling with the temps tho. it's getting up to 29c sometimes.

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Yea it can be fine then and them crap out later from the excess ppfd. Like I said 84F isnt bad unless the light is excessive. I had 84F average this run, 87F highs and was fine. Only time I got foxtails was with a 230w board light meant for a 3x3 in a 2x2 10” high on max. So it was like over 1200ppfd.

When you pass a manufacure recommendation in heignt, the ppfd goes to quite literally 2000. Idk what the ppfd map of your light looks like but a quick glance at that could help determine if thisnis the issue. Is it like 1000ppfd around the center and less on the sides like most lights at 12”? Not literally all lights but a ppfd map could give an idea.

If it was 1000ppfd at 18” which is possibly for some lights roughly speaking, that could explain. Going above manufacure limits like that the ppfd sky rockets. It starts to show later in flower.

Fish scale said:

Oh shit yeah, that's wild lol. Mine aren't that bad. Mine are just tiny little foxtails on the tips of the buds that are about 1cm in length

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You got any pics? It might not be foxtailing. Or fisting which is one Ive never seen someone have but learned about it long ago lol.

medidedicated said:

Yea it can be fine then and them crap out later from the excess ppfd. Like I said 84F isnt bad unless the light is excessive. I had 84F average this run, 87F highs and was fine. Only time I got foxtails was with a 230w board light meant for a 3x3 in a 2x2 10” high on max. So it was like over 1200ppfd.

When you pass a manufacure recommendation in heignt, the ppfd goes to quite literally 2000. Idk what the ppfd map of your light looks like but a quick glance at that could help determine if thisnis the issue. Is it like 1000ppfd around the center and less on the sides like most lights at 12”? Not literally all lights but a ppfd map could give an idea.

If it was 1000ppfd at 18” which is possibly for some lights roughly speaking, that could explain. Going above manufacure limits like that the ppfd sky rockets. It starts to show later in flower.

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Yeah I think it's about 1,100 - 1,200 ppfd or something like that. The only problem I have got is I can't raise the light up anymore because the carbon filter is in the way and I can't raise it past the carbon filter because the light is too big lol.

medidedicated said:

You got any pics? It might not be foxtailing. Or fisting which is one Ive never seen someone have but learned about it long ago lol.

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I will get some pics tomorrow bro, I'm not at the grow spot now but I will be tomorrow. It's like a fat dense rock hard bud sticking it's middle finger at me lol the foxtail is about 1cm in length on some of them and the ones that are showing the foxtailing trait are the more sativa phenotype's

Fish scale said:

Yeah I think it's about 1,100 - 1,200 ppfd or something like that. The only problem I have got is I can't raise the light up anymore because the carbon filter is in the way and I can't raise it past the carbon filter because the light is too big lol.

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Can you dim it to 75%? You could also setup filter outside of tent on top to push air out of filter instead. I did that to my whole setup to make way for boxfans, well worth it.

Are you sure it isnt just a sativa structure like this? This one looks like it is too but Ive been wondering with some other peoples opinion if its just the light and the bud structure produced. Same light that made my well known pheno grow foxtail like but not in definition foxtailing.

medidedicated said:

Can you dim it to 75%? You could also setup filter outside of tent on top to push air out of filter instead. I did that to my whole setup to make way for boxfans, well worth it.

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Yeah bro I have got it dimmed to 75% at the moment anyway because the temps are sitting around 28c - 29c and if I turn it up to 100% it goes above 30c so I gotta have it dimmed.

medidedicated said:

Are you sure it isnt just a sativa structure like this? This one looks like it is too but Ive been wondering with some other peoples opinion if its just the light and the bud structure produced. Same light that made my well known pheno grow foxtail like but not in definition foxtailing.

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yeah it's pretty much like that. but maybe slightly worse. But only a tiny bit worse

At high PPFD's, cannabis will foxtail. I had a grow in 2022 that fox tailed because I tried to light two plants with one light.





It wasn't until the damage had been done that I bought my little Vipar XS 1500.


This is that the larger plant looked like, long, wispy flowers instead of colas.




I grow my plants at high light levels, getting to 1000µmol by about day 35. The plants are very tall and yields are significant (usually exceed the seedseller's estimate by 50%) but I agree with the observation that the PhD at Fluence has talked about when he says that they saw fox tailing when PPFD exceeded 1100µmol (ambient CO2).

My most recent grow was a photo grow and some of the colas were at 1100±. I can't say I'd call that "fox tailing" because the colas were well formed.



This grow was run at 900-1000 (yeh "low light" !) and I'm seeing the same types of protuberances.



My experience has been that large colas are, frankly, ugly.






On the other hand, the sheer quantity of a crop grown at 1kµmol does make up for it.

Delps8 said:

At high PPFD's, cannabis will foxtail. I had a grow in 2022 that fox tailed because I tried to light two plants with one light.


View attachment 5467241


It wasn't until the damage had been done that I bought my little Vipar XS 1500.
View attachment 5467243

This is that the larger plant looked like, long, wispy flowers instead of colas.

View attachment 5467242


I grow my plants at high light levels, getting to 1000µmol by about day 35. The plants are very tall and yields are significant (usually exceed the seedseller's estimate by 50%) but I agree with the observation that the PhD at Fluence has talked about when he says that they saw fox tailing when PPFD exceeded 1100µmol (ambient CO2).

My most recent grow was a photo grow and some of the colas were at 1100±. I can't say I'd call that "fox tailing" because the colas were well formed.

View attachment 5467244

This grow was run at 900-1000 (yeh "low light" !) and I'm seeing the same types of protuberances.

View attachment 5467246

My experience has been that large colas are, frankly, ugly.

View attachment 5467247


View attachment 5467248

On the other hand, the sheer quantity of a crop grown at 1kµmol does make up for it.

View attachment 5467250

View attachment 5467251

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My buds are already well formed. The small 1cm foxtails on the tips of the buds that I have got only showed up around week 7 - 8 of flower so I'm guessing I'm good? I guess it only becomes a problem when the buds are foxtailing from the get go? from say week 3 of flower? I guess in my case it's down to the genetics and at the end of flower she tries to push out very tiny foxtails as a last ditch attempt to get pollinated? My light has been on 100% from week 2 of flower and she only displayed small foxtails @ week 7/8 of flower. I am struggling with the temperature at the minute so I have dimmed my light down to 75%. I'm going to be harvesting in the next week or two anyway so it's not like it's a massive problem for me. Cheers

Re. temperature— high heat destroys cannabanoids.

Back in 2021, Mitch Westmoreland did a study of the impact of temperature on cannabis and my opening sentence is from my notes from that video.

Fast forward to 18 months ago and student Mitch released a video in which he shared some of the research he did for his PhD thesis.

The video is here:



and this is one of the screenshots I took while watching the video.


If you head over to YouTube and search on "mitch westmoreland cannabis", you'll see a handful of vids. The one above is the full version, the version with Shane is a shortened version, and then there are a bunch of shorts. His 2020, video is there, as well. All good info but the "Future Cannabis Project" is the most comprehensive.

The net net for temps is in the graphic above. Westmoreland advises to keep temps warm temps, up to the mid 80's, through about the second week of flower and then drop temps so that the tops of the colas are <=78°. That's the max and we should be shooting for significantly lower.

I've read through his thesis, which he defended and is Dr. Mitch as of 8/24, and have attached a copy. One thing that you'll see in various parts of the document is that when he discusses how the plants reacted to changes in the grow environment, one cultivar may have had a negative impact but the other one that was tested didn't. Despite the fact that there were small differences in how they reacted, the "Discussion" sessions tend to recommend a given course of action because his belief is that, overall, it's better to do X even though the different cultivars reacted slightly differently.

Didnt you get a portable ac recently? What happened with that? I just turned my temps up to see if it spikes the rh less often if at all. It kinda helped. Kinda also preparing for summer where Il only have home ac but still will be in the 80’s in my room so Im trying to adjust now. Its working, I used to not be able to withstand it.

Fish scale said:

My buds are already well formed. The small 1cm foxtails on the tips of the buds that I have got only showed up around week 7 - 8 of flower so I'm guessing I'm good? I guess it only becomes a problem when the buds are foxtailing from the get go? from say week 3 of flower? I guess in my case it's down to the genetics and at the end of flower she tries to push out very tiny foxtails as a last ditch attempt to get pollinated? My light has been on 100% from week 2 of flower and she only displayed small foxtails @ week 7/8 of flower. I am struggling with the temperature at the minute so I have dimmed my light down to 75%. I'm going to be harvesting in the next week or two anyway so it's not like it's a massive problem for me. Cheers

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"foxtails on the tips" is good way to put it (doesn't need 700 words and a picture book!)

Those are my "protuberances". They did pop up in late in flower and I just figure it goes with the territory.

If you've got to dim the light to get temp down, agree 100% to dim the light.

medidedicated said:

Didnt you get a portable ac recently? What happened with that? I just turned my temps up to see if it spikes the rh less often if at all. It kinda helped. Kinda also preparing for summer where Il only have home ac but still will be in the 80’s in my room se trying to adjust now. Its working, I used to not be able to withstand it.

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Even with my portable ac unit the temps reach a max of 28c with the light dimmed to 75% and 29c @ 100%. Without the portable AC my whole crop would probably be ruined now because the temps would be about 32c lol. I also have to run my portable AC in a different room because there's no space for it in the grow room. If I had it in the grow room I could probably reach 26c @ 100%