GG4 Auto in late flowering: tip of leaves thinning up, looking burnt, turning light green to yellow

Troubleshooting
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1

Hello beautiful community. 1st grow here, she’s been really good so far, but in the past few days the leaves started to curl up a bit, today some brown spots, and the alarming bit is they are almost all turning light green to yellow.

I’ll try to summarise my journey so far:

She is a GG4 auto strain, started with a light-mix organic soil, a bit of veg organic fertiliser after week 4. As soon as I spotted some flowers, I switched to organic fertiliser for flowering.

Using ¼ strength every 2 days, give or take, with 1L of water. The fertiliser spec is NPK 3.2-3.5-4.2

All within the recommended specs and usage guide in the bottle.

PH water around 6.3, same for the run-off water. I’m diligent to check this. Also, EC, the sensor is only good when watering: EC been increasing over time, 1.8 couple days back, today 2.1 which tells me I might be over fertilising it?

Back to the problem:

Can’t say under-over watering as I only water when soil begins to dry out, that seems to be within the spec.

Heat stress? Could be, I don’t have an AC in my tent (tent size 2x4 or 60x60x140 in old money) but a good exhaust fan (100 ACH is the kind of setpoint I normally leave at) and no intake fan, average 50% RH but temp varies 18 to sometimes 30 (the higher bit only for a few hours during a sunny afternoon, again, no AC and the room the tent is in gets that warm sometimes). And of course, the RH as well, peaking at 65% colder and 45% warmer.

Stress due to pruning? Could also be but I been doing it ever so little, giving a few days in between, and checking her reaction. She’s been enjoying this as I can tell, a human helping her out getting rid of leaves shading her buds, or those bottom ones that were dying anyway. I guess no more pruning is required right now.

Over-fertilising? That is my bet, and I shall stop with the fertiliser unless told otherwise.

Since I’m beyond amateur I decided to post the question here to get some expert advice.

Thanks in advance for reading my question, cheers guys.

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@bytearray

Hello growmie and happy growing. I don’t see a total number of days it’s been growing and or in flower.
Could just be nearing end of life colors but hard to tell in the pictures for sure or not.
And I’m no expert either lol.
Hope someone else can chime in

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Cheers matey. Happy growing to us all. She is 8.7 weeks old, flowering for 3 weeks now. I guess a few more weeks of flowering? I’m just worried about the increase change in leaf colour, and the tips becoming yellow or brown. I had quite intense light before so I pushed the 150W LED back to 90% and 27cm away from the top of the main bud. Gonna observe what happens the next few days. And will stop fertilising it for the next few days as well, just give it plain 6.3 PH water.

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@bytearray

Here’s my sour diesel at about 11-12 weeks she went over 100 days total. She got a little crispy there at the end. You are doing good keep up the good work

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Over fertlized. No biggie but do a soil slurry test for ec an ph. Flush if needed.

If you are using a dry fertilizer you are definitely over doing it. Stop. Switch to liquid hydroponic fertilizer.

Do the slurry test asap.

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Thanks mate. That’s where my money was. Thing is I been using an organic fert ([COMPO GROW ORGANIC STARTERKIT] 1/4 strength, should I continue using it and just leave 4-5 days off, with lots of water in between, instead of the usual 2 days? Do you think she is in fact 5 weeks from harvest, or 2 weeks as a mate of mine said? If the latter then I should stop applying the fert as the manufacturer said.

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Just done a slurry test, it has shown a ph of 6.7 unfortunately I can’t do EC because the sensor is in the pot, but that sensor seems accurate as per my research, and it shows a sensible value every time I water as it gets in touch with the whole thing. Last time (yesterday morning) it showed an EC of 2.1 which is what I been aiming for during flowering. During veg I kept at 1.3 to 1.5

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Welcome to the forum. Yes. At least 5 weeks more… I typically got best results with gg around 10 weeks of flower. Slight amber since was for pain and sleep. You look hot. And gg is super ph finicky.i personally would add something like recharge. Fire up the life since organic nutes. Helps stabilize uptake and regulate ph. Most dry ammendments take a little time to break down. The liquid stuff is super available right away. Easy to overdo it. Your light at 150w is not going to cook that plant unless you are inches away. Temps are ok. I have hit 30 summer time with them. If worried just turn on at night and off during day. I cloned a gg bean 2 years straight. About 7 or so generations. Finicky bitches but solid hammer weed. Just my thoughts. Gonna need stakes. They get very top heavy.

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Your light still sounds like it’s too close at 90% and 27cm, so that’s like 10 inches away. I’d be more like 12-16 inches away from tops. Do you have the photone app to check ppfd?

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Many thanks mate, its great read your experience with this strain. Wow, 7 generations of clones…congrats. Mine is flowering FAST, fattening up the buds, this is from a few hours ago. She is 63 days old today. I could not find the Recharge you talked about but perhaps this is a local supplier’s equivalent? https://lucky-plant.de/products/pflanzenstarkung-tablette-2x-je-20-tabs

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Thanks brother. I have indeed moved up the light to be 30cm away (12inch). Great app, thanks for sharing. With the new height its reading 1400 PPFD. It’s a Viparspectra XS1500 light, the chaps at Viparspectra said that it should be 1200 at that height:

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Anyway the app is close enough, probably has a 10-15% accuracy. I forgot how powerful this light is and I think I have been stressing her being so close, after a few hours of changing height I can see some improvement in happiness.

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Nice bro, you’re on the right track. 1400ppfd is pretty high still unless your running co2. I never go above 1200 ppfd and a lot of people will say that’s too high even. 900-1000 is where I like to be unless I got a lot of lower bud sites struggling for light, then the very tops get blasted.

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For comparison, GG ILGM auto that I grew last year. They looked rough at the end. I think they went near 13 or 14 weeks. Your plants look great.

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for those that were very kind to reply to my topic and provide great advice, I created another one related to time to harvest, in case is of interest:

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I think that I am creating a bond with this plant not easy to let her go…

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She is now 94 days old…13.4 weeks of which 10.4 are flowering. Reckon the axe is coming down within the next few days.

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