Day 25 flowering dark/black new growth at bud sites

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tomat

tomat

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Hi everyone,



First time grower and up until now (despite various self inflicted screwups) everything's gone reasonably smoothly.

The plant's a photoperiod critical strain, day 25 of flower, flora trio nutrients and calmag with plain water every second feed in canna terra professional plus soil. The water I feed it is ph'd at a consistent 6.1 and I occasionally adjust it up or down a minor couple of points (I read that different nutrients are absorbed across a PH range). It's under a 240w led qb board.



Just in the last week I've seen new growth at bud sites begin to darken to an almost black colour (the slight nute burn at the tips was an earlier bungle of mine that seems to have stopped progressing). The leaves don't seem to be wilting or yet look obviously unhealthy beyond the weird coloration, but I've got absolutely no idea what this is/what's causing it. I've seen people mention mould etc but that doesn't seem to fit this only happening at new growth areas and nowhere else on the plant.



If anyone has seen this before or has any tips as a complete novice I'd appreciate it!
 
lvstealth

lvstealth

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what are your day/night temps?

xanthophyll and chlorophyll, the way i understand it, the chlorophyll is what makes plants green, but the xanthophyll makes purple. all the plants have it, just some show it easier (like the purple kush or GDP) often a large differential between day and night can bring out the purple. these are the energy production facets, the xanthophyll makes about 30% of your plants energy. so they are not just there to make things purple. the green is more efficient than the purple.

critical is not normally purple, but there are phenotype that display the purple. that being said, the plant should be more potent without the purple. the green is a much better energy system

what i am trying to say is... it could be totally normal for that phenotype. check your temps day and night. it wont be detrimental, but it is not the best either.

btw, i know nothing, i was just thinking i wanted purple, i think it is pretty. so i read and read and found this info useful.
 
tomat

tomat

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Thanks for the info, you may know nothing but that's a good bit more than I seem to !

I did indeed have a look around for other peoples critical grows to see if this is a regular change (as you say, it's not), in phenotypes that do tend toward purple
is it normal for that to occur halfway through flowering or would you expect it to show that colour from the start?

I'll keep a closer eye on day/night temperatures, I haven't kept track of them precisely since I was satisfied they weren't getting worryingly extreme in either direction,
the tent is roughly 23-25c°C during the day and about 18-20°C at night.
 
lvstealth

lvstealth

Supporter
just about any stress can bring on some purple, often the stems. the way i understand it, the purple ones, i mean the ones they bred to show purple, they selectively bred the chlorophyll to fade near the end so it will turn purple not long before harvest. but any plant can turn any part purple. the stiples, the leaves, the stems, the flowers... any of it. they do not show from the start. it is almost always (except stems) in flower (there are exceptions... basically if you are killing it it might turn purple in veg), and almost always in late flower, maybe mid to late, if it is a short flowering strain.

it pretty much has to have the green to get to the point where it flowers. in even the most secure solid strains, a 30 degree change day to night will purple things. a 10 degree change day to night can cause it though, and often does in strains that have that characteristic.

can i ask where you got the seed? i was reading about a pheno of critical from one company that does turn purple about 1 in 50 seeds.

in the end, i wouldnt worry about it. do watch the temps though. seems to be the most predictable factor in the color change.

just curious, does it smell differently from the others?

can you post updates when you harvest and cure? id like to know if it effected the yield, flavor or potency.
 
tomat

tomat

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Thanks again for all the info, it's very useful, the colour change was so different to anything I'd seen before that I thought it had caught the plant equivalent of the black death or something!

The seeds are from RQS (https://www.royalqueenseeds.com/feminized-cannabis-seeds/133-critical.html), I have two others which are further along, just about week 7 now, so in theory close to harvest but no amber trichomes yet and no purple growth on either. I'll be sure to post some updates when they're all harvested and cured to see if there's any obvious difference.
 
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