Hey,
here are my two Black Mango. Growing in soil in a 60x60x160 cm tent and 125W LED
73 days after first pistils. They did go in some sort of reveg during a severe heat wave, when I was not at home and could not open the windows during the night. Now the additional grow has stopped. I can exclude problems with the light, timing or light leaks.
Of course, this is a wild outdoor landrace, so this
is all experimental.
BM#1 had to be discarded due to severe intersex traits,
here is #2
They are now under 10.5h of light, 13.5 h of darkness
Mmm.. interesting reaction. You say is because the hot but is the first time I see something like this because of the hot. Usually from my experience they reveg becuase of the light circle.
But I’m ready to learn why the hot can be claimed responsable for this? (I took the liberty to edit the title of the topic because I never heard about this phenomena so I hope others will join the discussion about this. I hope you agree.)
After this to happen I don’t think they can do good flowers anymore. Personally I will let to complete the reveg, take some cuts and use them to make flowers. But again, if you are trying another path is also interesting and you can document what happens and we can all enjoy to learn from real time experience.
Again from my prospective: if you want to send them to complete flower anyway at least you can clean some extra sprouds and all the one finger leaves.
In temperate cannabis strains, genes trigger a definitive hard stop to vegetative leaf production once flowering begins. In equatorial varieties, these genes are often inactive or under-expressed.
The Rare Case: Even under a perfect 12/12 indoor light schedule, a landrace sativa can spontaneously fire its vegetative growth hormones.
The Symptom: It will grow widely spaced internodes and continue to sprout single-leaflet fan leaves directly out of its airy floral clusters.
It looks identical to an accidental, light-leak-induced reveg, but it is entirely dictated by its native genetics.
Source: Sensi Seeds
(for the moment your is the first case that have been reported to me, so mine is pure investigation mode)
Landraces from places like the Oaxacan Highlands or the valleys of Southeast Asia are finely attuned to changes in the sun’s angle and spectral quality rather than total hours of darkness.
The Indoor Glitch: If you are running full-spectrum LED grow lights that feature advanced sunset/sunrise dimming functions, or if the bulb’s spectrum degrades over a few months, a subtropical landrace may interpret that tiny spectral shift as a seasonal change.
The Reaction: Even if your digital timer registers exactly 720 minutes of light and 720 minutes of dark, the plant may sense a shift in the red-to-far-red light ratio, causing it to stall flowering and attempt to reveg.
Source: Amsterdam Seeds
Yes. I also read suggestions (because I never tried indoor) about give a 11/13 or even 10/14 light/dark circle to make sure. Anyway you got a very tuff complicate individual there 
what I can say about Thai landraces that they surerly feel the increase of minutes , maybe even seconds, on the light circle. So even if you keep many hours of dark but the light time slightly increase everyday even few days they will reveg but to re-flower they will not be same fast.
Anyway to me it looks that also the other plant in the pictures is foxtailing. So I feel quite confident that something happened to the light wihtout you to be able to know what. If this are seeds from me I would like to send them to you again to try another run from “fresh”. You can even choose another type more easy to control like the Thai Gasolina I think better.
Hot temperatures does make them foxtails lot, the heatwave in uk made some of my strains to foxtail. maybe just landrace foxtail?
You right. Foxtailing and Reveg is not the same
Foxtailing refers to buds developing abnormal, tower-like or spike-shaped extensions. It is usually a stress response to excess heat, intense light (too close), or genetics, where the plant builds new calyxes on top of already formed ones.
Re-veg (Re-vegetation) happens when a flowering plant reverts back to its vegetative growth state. This is typically caused by light leaks in the dark period or a messed-up timer, and is visually identified by single pointed leaves growing out of your buds.
I just remember having read those successive reflowerings on AceSeeds Instagram when he talks about his Thai Chang Mai selection: “As an authentic pure tropical sativa, the flowering of this Thai variety from Chiang Mai is long, developing in successive reflowerings, and showing a very high resistance to humidity and botrytis type fungi.”
Dear,
thanks for all the feedback and participation.
Here some more info. Seeds sprouted April 1, switched to 11/13 on May 1, first pistils May 10. 10.5/13.5 on July 4 after the heatwave and when I saw the reveg/extra stretch.
3 people responded on the other forum to my pics with the reveg at that time, stating they had similar experiences. Here is a link (by permission of Prempavee):
This and the following posts. User PapaThai postet two links with pics of a Thai plant after a heat wave similar to mine.
Currently, I have 28°C and 50% humidity during the day and around 19-20°C during the night.
This particular plant I found very unusual and attractive during late veg and early flowering:
The lady with the ponounced foxtails is a Oaxaca 79 crossed with a Chiang Mai Thai male. I will harvest her this weekend, just under 11 weeks of flowering. Whatever caused the foxtailing, heat, genetics, the stress I imposed on her, it sure did not prolong flowering for very much.
I will keep you all updated about the Black Mangos
11 week the Oaxaca was looking almost ready 
but the black Mango still in early flower, she will need at least another 11 and after this is hard to know.
Keep updating I’ll follow same of a TV series
Yeah, I have had problems with a light timer in the past, so I know what can happen to light cycles. I now have been using a programmable power plug that is very accurate and reliable. There is no other light source in the tent (LEDs from plugs, power sockets etc.). I even checked inside the tent during dark phase and the grow tent is in a room with shades down.
I agree there has been revegging, but I can’t identify any problems with light cycle or pollution. And it’s like the 8th grow in that tent in the same spot.
11 more weeks for the Black Mango will be a challenge… LOL
I dont know what your timer is
But i once put an analog timer on opposite 13 hours of light and 11 hours off.
Some digital timers can have multiple settings and turn on just one min in the dark
Anything electronic or analog can misbehave
Some genetics are also so sensitive that a short visit in night can disturb them
I’m just making sugestions to help
I have never had anything but hermies come from high temp spikes
Hope you find out why
Thanks Nevlu, everything correct.
Your post made me double check the timer settings. It has 16 different switches. But all is ok, it turns the light on at 9:45 h and off at 20:00h. That is also easily observable.
Harvested the Oaxaca x Thai today, 75 days after first pistils
Checked once more for light leaks (lights off, dark room, moved a strong flashlight around the tent), but could not find anything. But one more thing.
I had posted this on the other forum, but part of the information was lost after Prempavee invited me here. 
Sorry about that.
It’s the fact that I did repot the Black Mangos from tiny 1 l pots to 6.5 l pots when they were altready 10 weeks old (30 days after first pistils). So these were serverely rootbound of course. I had managed to keep them fairly happy, though. The reason why this was so late was another plant in the tent that needed more veg time.
That was about 3 weeks before I noticed the strange growing behaviour (I was out of town and the heatwave happened during that time).
So I did some more research (Dutch Passion, Grow Weed Easy, Royal Queen Seeds) and let the Google AI sum it up. Here is what it came up with, sounds plausible to me:
Scenario: Re-potting a 10-week-old, heavily rootbound Black Mango (Thai landrace) from a small 1 L pot to a 6.5 L soil pot on day 30 after pistils appeared, under an 11/13 light cycle, amidst an ongoing heatwave.
Primary Concern: Whether this combination could trigger revegetation (revegging).
No True Revegging: Re-potting cannot trigger true photoperiodic revegging. As long as the strict 11h light / 13h uninterrupted darkness schedule is maintained without light leaks, the plant remains genetically in its flowering phase.
Fake Revegging Symptoms: However, the plant can display severe pseudo-revegging symptoms (single-finger leaves, stall in bud swelling, leafy growth) due to environmental stress and sudden nutrient availability.
Nitrogen Surge from Fresh Soil: The rootbound plant suddenly absorbed a large amount of Nitrogen (N) from the new 6.5 L soil. Equatorial Thai Sativas are notoriously sensitive to Nitrogen mid-bloom and react by growing leaves out of flower sites.
Heatwave Acceleration: High temperatures (>28–30 °C) disrupt floral hormones, causing foxtailing (towering bud structures), loose/airy flowers, and extra leaf growth directly from the buds as a panic response. Combined with fresh soil and high metabolism, heat acts as a major catalyst for these growth anomalies.
Nutrients: Hold off on adding any fertilizers. The fresh soil provides more than enough nutrients for the coming weeks.
Environment: Increase exhaust ventilation, shade/cool the black 6.5 L pot if it’s absorbing radiation, and slightly reduce light intensity or increase light distance to lower overall stress.
Watering: Water cautiously—the compact inner rootball will take time to expand into the new soil volume, so wait until the pot feels noticeaby lighter before watering.
Uppscaling the pot to 6 times it’s size while flowering i think explains the phenomena
Heatwave probably made it worse
An indica wouldn’t have done that but because sativa and especially landrace can grow a lot during flower
I messed up so mutch with growing these the last years that i found out that one
The plant is smart and sensed it had big enough room to put out some extra
I bet you still can get good flowers and probably better than you would have in a 1 liter pot
Good you got your answer 
Heat stress does not directly cause new growth (revegetation) in cannabis plants, but in some cases, stressed plants — especially flowering-stage plants — can produce new bud growth on top of existing colas. This is often called “foxtailing” and is a visible sign of heat/light stress Seeds Here Now+1.
When cannabis plants are exposed to prolonged high temperatures (often above 80–85°F / 27–29°C) or intense light, they may respond by pushing out new spires of bud tissue toward the top of the plant. This is a survival mechanism to get more buds into cooler air, but it’s not true vegetative regrowth — it’s a stress-induced flowering response Seeds Here Now+1.
True vegetative regrowth means new leaves or stems forming from healthy tissue, often after damage or pruning.
Foxtailing is a flowering-phase stress response, not a recovery of vegetative growth. It can look like new growth, but the plant is still in the flowering stage and may be sacrificing quality for quantity Seeds Here Now+1.
Vegetative plants can recover from heat stress if the stress is not severe, but it’s best to extend the vegetative phase slightly to allow recovery Tutto Su Giardinaggio E Progettazione Di Giardini.
Flowering plants under heat stress may continue flowering but often with reduced yield, lower trichome density, and more foxtailing novaseedbank.com.
Seaweed kelp extract and proper cooling can help plants recover, but the plant’s ability to regrow healthy vegetative tissue depends on the extent of damage Grow Weed Easy+1.
Heat stress can trigger foxtailing — new bud growth on top of colas — but it does not cause normal vegetative regrowth. If your goal is to recover healthy vegetative tissue, focus on preventing heat stress, maintaining optimal temperature and humidity, and allowing time for recovery. Foxtailing is a sign of stress, not a sign of healthy regrowth.
I have seen in another forum that they are recovering well! They even start to show some purple color a little bit! Share tham here too we really are interested to follow up with this
