Tacoing Leaves During Late Flower

[tronN00dles]

Hey folks,

I'm currently running my first photo grow: https://www.autoflower.org/threads/...ack-and-bubba-kush.84913/reader/#post-2490512

I'm approaching the finish line, currently in Week 7 of flower, over the past week or so, my upper most fan leaves have started tacoing. I understand this is primary a light or heat issue, but my environment seems pretty well spot on. See the infirmary form, below:

Problem: Tacoing, dry, crispy fan leaves in late flower.

Medium/grow method: Coco/perlite, high-frequency fertigation (3x a day)

Feed: and supplements used: General Hydroponics 10-part "light" chart. Currently following Week 7 (Micro, Bloom, Grow, Ripening). Note, fed cal-mag up until Week 6 as per feed chart. Nute mixes currently around 500ppm, run-off normally held no more than 150ppm above intake, however this week, run-off is currently less than intake. I just fed at 500ppm, run-off around 420ppm. pH usually around 5.8. Last feed at 6.1.

water source: Tap water, 40ppm out of tap.

Strain/age: Green Crack by Canuck Seeds, day 47 of flower.

light used: Two HLG 135W LEDs, currently drawing 270W from wall. PPFD from 600-900 across canopy, averaging around 700 PPFD.

Climate: Strict adherence to VPD charts. Current leaf temps around 22C, ambient temp 24C, RH around 42%.

Additional info: A few fungus gnats stuck to yellow sticky tape. Also see comment above re: cal-mag. Also, only the upper fan leaves are affected. Ventilation fans in place but nothing too direct on many leaves, more so above and below canopy. Also had some high EC issues many weeks ago so there's some burnt tips, but EC issues were straightened out early in flower.

Any ideas?

I'm kinda thrown for a loop here as everything seems to point towards light or heat stress, but as per the info above, my lights and environment seem to be in check. The fact only the upper leaves are affected indicates light, but I'm reading an average 700 PPFD here. The plant is healthy otherwise and I'm expecting 7-10 more days to finish as per the trichromes. Could this just be end of life stuff? I half expected so see some fall-fade by now, but the plant remains super green. Maybe that's why they call it Green Crack lol. Anyway, has anyone seen tacoing during the final stages of flowering before? Or is there something else going on here?

A few pics:

Thanks in advance!

-tron

 

[Del boy]

Hey folks,

I'm currently running my first photo grow: https://www.autoflower.org/threads/...ack-and-bubba-kush.84913/reader/#post-2490512

I'm approaching the finish line, currently in Week 7 of flower, over the past week or so, my upper most fan leaves have started tacoing. I understand this is primary a light or heat issue, but my environment seems pretty well spot on. See the infirmary form, below:

Problem: Tacoing, dry, crispy fan leaves in late flower.

Medium/grow method: Coco/perlite, high-frequency fertigation (3x a day)

Feed: and supplements used: General Hydroponics 10-part "light" chart. Currently following Week 7 (Micro, Bloom, Grow, Ripening). Note, fed cal-mag up until Week 6 as per feed chart. Nute mixes currently around 500ppm, run-off normally held no more than 150ppm above intake, however this week, run-off is currently less than intake. I just fed at 500ppm, run-off around 420ppm. pH usually around 5.8. Last feed at 6.1.

water source: Tap water, 40ppm out of tap.

Strain/age: Green Crack by Canuck Seeds, day 47 of flower.

light used: Two HLG 135W LEDs, currently drawing 270W from wall. PPFD from 600-900 across canopy, averaging around 700 PPFD.

Climate: Strict adherence to VPD charts. Current leaf temps around 22C, ambient temp 24C, RH around 42%.

Additional info: A few fungus gnats stuck to yellow sticky tape. Also see comment above re: cal-mag. Also, only the upper fan leaves are affected. Ventilation fans in place but nothing too direct on many leaves, more so above and below canopy. Also had some high EC issues many weeks ago so there's some burnt tips, but EC issues were straightened out early in flower.

Any ideas?

I'm kinda thrown for a loop here as everything seems to point towards light or heat stress, but as per the info above, my lights and environment seem to be in check. The fact only the upper leaves are affected indicates light, but I'm reading an average 700 PPFD here. The plant is healthy otherwise and I'm expecting 7-10 more days to finish as per the trichromes. Could this just be end of life stuff? I half expected so see some fall-fade by now, but the plant remains super green. Maybe that's why they call it Green Crack lol. Anyway, has anyone seen tacoing during the final stages of flowering before? Or is there something else going on here?

A few pics:

View attachment 1409603

View attachment 1409604 View attachment 1409605

View attachment 1409606 View attachment 1409607

View attachment 1409608


Thanks in advance!

-tron

Hello i had the same problem with a blue ammo i thought it was light so turned it down stayed the same all through flower then on the next grow same problem even with light turned down then on the next grow turned light up droped temps down to 24C no taco leaves grow it again same temp perfect
hope this helps

 

[FarmerJake]

That’s a plant to be proud of, no advice as it’s nicer than any I’ve grown!

 

[elcoloan]

While the experts come, let me chip in.
If you are sure it's not due to russet or broad mites, and heat isn't an issue as it seems you are not even over 24C... it might be your medium has too low pH. If you can, measure the medium's pH or just keep watering at 6.1-6.3... remember root zone pH usually lowers during flowering. Not sure you'll see any improvement this far in the run if you do find it's low root zone pH or if you start watering with higher pH, but it has worked for me and my growpals when every other normal tacoing cause has been ruled out.

 

[tronN00dles]

While the experts come, let me chip in.
If you are sure it's not due to russet or broad mites, and heat isn't an issue as it seems you are not even over 24C... it might be your medium has too low pH. If you can, measure the medium's pH or just keep watering at 6.1-6.3... remember root zone pH usually lowers during flowering. Not sure you'll see any improvement this far in the run if you do find it's low root zone pH or if you start watering with higher pH, but it has worked for me and my growpals when every other normal tacoing cause has been ruled out.

I don’t have a way of measuring the medium directly. I typically fertigate at 5.7-6.2 and have never checked run-off pH, only ppm. So I just checked my run-off pH for the hell of it, and it was 4.6. My understanding is that run-off pH in coco isn’t particularly useful, but even still, that seems low. Is a flush up closer to 6.3 in order?

 

[Old Sage Seeds]

I think you may have cut the cal-mag a bit early. Usually in coco during late flower I reduce cal-mag to half until the week before flush. Could also be pH. hard to say.

 

[Mañ'O'Green]

The plants look overfed to me with too much N. More likely though the RH is too low for these strains and causing the tacoing. You are right on the edge at 42%RH

 

[tronN00dles]

The plants look overfed to me with too much N. More likely though the RH is too low for these strains and causing the tacoing. You are right on the edge at 42%RH

View attachment 1409697

Thanks pal! Yeah she's been super sensitive to nutes. I pretty well have been feeding auto-strength nutes for this photo from late veg to mid flower, 500-600ppm. Had a bit of an EC spike a few weeks ago and the tips have been burnt ever since.

I will increase the humidity a bit. The tent is in a closet that has a dehumidifier of it's own, so the closet itself can get pretty dry, around 35%. The leaves are dry to the touch though so maybe I'll up the closet humidity a few points and aim for a tent RH closer to 45%.

Cheers,

tron