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Why are top leaves yellowing? 4th week of flower

Embarrassed_Corgi_64
Embarrassed_Corgi_64started grow question 11d ago
Why are the top leaves yellowing but not the bottom leaves? Overwatering, pH lockout, deficiency, light stress?
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Leaves. Color - Yellow
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Organoman
Organomananswered grow question 9d ago
Deficiency of trace elements/tace minerals is most likely the cause. Excessive calcium.........i.e. giving cal/mag every time you water, can cause problems. Cal/mag every 10 days or so is more "normal"..........unless you are growing in coco.
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Still_Smoq
Still_Smoqanswered grow question 10d ago
Check your watering habits, make sure your PH is correct and don’t let the light source get too close to your plants.
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John_Kramer
John_Krameranswered grow question 10d ago
I assume that this idjit with mulder chart is blind xD And also stupid or both... U,d study in scool more properly 🤣
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Ultraviolet
Ultravioletanswered grow question 10d ago
Iron is critical for the processing of chloryphyll. top leaves yellowing but not the bottom leaves? Leaves that do more photosynthesis need to replenish chlorophyll at a higher rate. When a medium becomes oversaturated, especially soil, iron can become unavailable to plants due to chemical changes that lock it into forms that are difficult for roots to absorb. Iron uptake is significantly affected at a pH above 7 because high pH causes ferrous iron (Fe²⁺) to oxidize into ferric iron (Fe³⁺), which then forms insoluble ferric hydroxide, making it unavailable for absorption. Oxygen, oxygen, oxygen, nothing good can happen in a soil that doesn't have oxygen, a pot that big will require strong negative pressure to ensure moisture is being moved within an adequate timeframe, very easy with a pot that big to have dead spots, in nature oxygen is diffused via high and low pressure fronts, in tents indoors we don't have those, so we create them through negative pressure, vital for big pots. Look like you are feeding lots cal mag every week, far too high RH%, she isn't able to move water or respire as well as she wants, causing a backlog and potential pH skew, tips starting to burn meaning salt capacity reaching limit, fairly sure you used organics so hard to measure how much nitrogen you still have breaking down in there, that could also potentially skew ph over 7. Feed her some carbon sugars, P and K after you get her pH sorted, Iron lockout, but there is probably lots of iron available, you need to get your RH under control and get water moving in that tent, especially with such a big canopy. Gluck.
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Ratle
Ratleanswered grow question 11d ago
from your diary it's way to humid for flowering. With that high humidity and temp, transpiration is affected. I would get that under control first before throwing things at her and check light distance and I assume you have fans running. I only water when pot is light weight when lifted, usually every 3-4 days during flower when she is drinking much more. I have a 5 gallon fabric pot and water with just over half a gallon each time. I see nothing to freak out about. There's some slight curling of tips, no cupping going on and leaf tips look fine, minor burn so that leads me to heat stress. Good luck
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00110001001001111O
00110001001001111Oanswered grow question 11d ago
yeah, that 2nd picture it looks even more apparent... you can see the yellowing is mostly in the central areas and the sides are a more normal lushness.
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00110001001001111O
00110001001001111Oanswered grow question 11d ago
There's more than one possible cause... -Too much light -- hard to rule out from pictures. -too much P and/or K (both cause chlorosis in new grwoth and skinny leaves in new growth -- I don't think that is the case here, but.... The progression isn't quite right for S-def, so that can be ruled out. There are a couple trace elements that might cause paling at the top, but that'd be really rare. You want to do your due diligence and ensure these other possibilities are not the cause, but i'd guess it's a tad too much light. 1" higher might be enough as it looks like a less severe issue going on and only needs a small adjustment whatever it is.
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White_Rabbit420
White_Rabbit420answered grow question 11d ago
N … Mg … S .. die Reihenfolge zum checken
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AsNoriu
AsNoriuanswered grow question 11d ago
Open Mulder chart and you will see how loonatic Kramer is. There is no relationship between elements he states. In my mind, ph issue together with overfeeding, that caused plant to be unhealthy, then even light intensity can cause troubles. You had troubles long time before, now just aftermath shows up.
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Growtendo64
Growtendo64answered grow question 11d ago
Yellowing at the top in week 4 of flower usually points more to light stress or a lack of nutrients like iron or magnesium, since deficiencies that start at the bottom (like nitrogen) don’t fit here. Check how close your light is to the canopy and back it off a bit if it’s too intense. Also make sure your pH is in the right range so the plant can take up micros
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John_Kramer
John_Krameranswered grow question 11d ago
CalMag issue the front one has Mg excess and Ca lock the one at back contrariwise due to this u have also P,K problem
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ibbzy
ibbzyanswered grow question 11d ago
Raise your lights or dim them, looks like like light stress
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