Help! yellow coloring of leaves 27 days into flower

Thank you for that.
I guess I just assumed everyone knew what they were talking about when they were saying get my pH to 6.8.

I don’t know anything about who told you what but if you want to fill out a support ticket we can get you back in balance my friend

will @garrigan62 can help you out he’s got a good eye, also @Donaldj is back, so please fill out a support ticket so we have your info

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( This post is large i sorry but he needs to know this )


Here are two pic’s that show why i beleive that’s it’s

Potassium (K) Mobile Element and Macro Element
Potassium plays a big role as well. Having good amounts of potassium in your
plants helps in having sturdy and thick stems, disease-resistance, water respiration,
as well aids in photosynthesis. Potassium is also found in the whole plant. It is
necessary for all activities having to do with water transportation. Potassium is
necessary for all stages of growth, especially important in the development of Buds.
Having to little of Potassium in your plants causes the plants leaves to show
retarded growth and show a scorched tip and edges around the leaves. Plants may
stretch and your branches can be easily broken or weak. Don’t get this deficiency
confused with iron, because it almost acts like iron but to tell the difference in the
two is:for potassium the tips of the leaves curl and the edges burn and die. Older
leaves may show a red color and leaves could curl upwards. Dead patches
(Necrosis) can happen on the margins of larger fan leaves thus, the leaves will
eventually die off and turn brown. The Older leaves willshow different patches of
color (mottle) and turn yellow between the veins, following by whole leaves that
turn dark yellow and die. The plants overall growth slows down, mostly when they
are in vegetative stage. To little amount of potassium also slows the growth of buds
during flowering stages. Dark edges will appear around the edges of the leaf when
the deficiency is starting to happen. When your Relative humidity is low, you can
almost bet your going to soon get a potassium deficiency from your plants
Potassium can get poorly absorbed when having too much Calcium or ammonium
nitrogen, and maybe cold weather. Having to much sodium (Na) causes potassium
to be displaced. SO keep those in mind… Parts affected by a Potassium
Deficiency are: older leaves and leaf margins.
When you have too much Potassium in your soil, it can lead to big troubles, like salt
damage and acid fixation of the root system, as well as too much potassium can
cause a calcium deficiency. Your fan leaves will show like a light to a dark yellow to
whitish color in between the veins. Due to a molecular imbalance, potassium toxicity
can cause a reduced uptake and lead to the deficiencies of Mg, and in some cases,
Ca. Also leads to the other nutrients to not be absorbed properly leading to lots of
other deficiency such as: magnesium, manganese, zinc and iron and can cause
problems with calcium as well.
Problems with Potassium being locked out by PH troubles
Soils with excessive Leeching and High ph soils and or water.Soils that are
potassium fixated. An excess of kitchen salts (sodium) in the root
Potassium gets locked out of soil growing at ph levels of 4.0-5.5
Potassium is absorbed best in soil at a ph level of 6.0-9.5. (Wouldn’t recommend
having a ph of over 7.0 in soil) anything out of the ranges listed will contribute to a
Potassium deficiency.
Hydro and Soil less Mediums
Potassium gets locked out of Hydro and Soil less Mediums at ph levels of 4.0-4.5,
Potassium is absorbed best in Hydro and Soil less Mediums at ph levels of 4.7-5.3,
6.7-8.5. (Wouldn’t recommend having a ph over 6.5 in hydro and soil less
mediums.) Best range for hydro and soil less mediums is 5.0 to 6.0. Anything out of
the ranges listed will contribute to a potassium deficiency.
Solution to fixing a Potassium deficiency
Any Chemical/Organic nutrients that have potassium in them will fix a potassium
deficiency. Again Peters All Purpose plant food 20-20-20, will cure the potassium
deficiency , Miracle grow Tomato plant food, Miracle grow All purpose plant food.
( Only mixing at ½ strength when using chemical nutrients, or it will cause nutrient
burn!) Some other supplements of potassium are: Wood ashes, which are fast
absorption, Kelp Meal, which is medium absorption, Greensand, which is slow
absorption, granite dust, which is slow absorption. Sulfate of Potash, Sulfate of
Potash Magnesia, Muriate of Potash, which are medium absorption. FOXFARM
GROW BIG HYDROPONIC CONCENTRATE, which is fast absorption.
(FFGB can bring your ph down as well) Earth Juice Meta-K, which is fast acting.
(Can bring down your ph as well) Leaves will never recover, but the plant willshow
recovery after about 4 to 5 days when using a fast acting nutrient.
Note: Wood Ashes, can make your ph go up a bit, so please monitor your ph when
using it.
Now if you added to much chemical nutrients and or organics, (which is hard to
burn your plants when using organics) you need to flush the soil with plain water.
You need to use 2 times as much water as the size of the pot, for example:If you
have a 5 gallon pot and need to flush it, you need to use 10 gallons of water to rinse
out the soil good enough to get rid of excessive nutrient’s

Copy/Paste: This “Support Ticket” Into Your Forum Post.
Answer These Simple Questions The Best You Can.
If You Do Not Know, Or Do Not Use Something; Just Say So = Na

Strain; Type, Bag Seed, Or Na

Soil In Pots, Hydroponic, Or Coco?

System Type?

Ph Of Runoff Or Solution In Reservoir?

What Is Strength Of Nutrient Mix? Ec, Or Tds

Indoor Or Outdoor

Light System, Size?

Temps; Day, Night

Humidity; Day, Night

Ventilation System; Yes, No, Size

Ac, Humidifier, De-humidifier,

Co2; Yes, No

Add Anything Else You Feel Would Help Us Give You A Most Informed Answer. Feel Free To Elaborate, But Short,

Questions And Facts Will Help Us Help You 


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I just posted a support ticket in beginner forum with title ‘discoloration of leaves’ with all known facts…

You guys are awesome by the way, for helping me out. I can’t smoke anymore due to employment drug testing but this is for my wife who has medical issues. I am becoming very passionate about this whole process. We really appreciate it!

[quote=“garrigan62, post:23, topic:7919”]
Strain; unknown Type, Bag Seed

Using ILGM nutes. Just flower booster at this time. 1-1/2 teaspoon per 1 gallon feeding every 3 or 4 days

Soil In Pots, Fox farm ocean forest

System Type? Na

Ph Of Runoff Or Solution In Reservoir? Has been 5.8-6.0 in flower went up to 6.3 yesterday 34 days into flower

What Is Strength Of Nutrient Mix? Na

Indoor Or Outdoor: indoor

Light System, Size? (Was using 3, turned 1 off) 2 CFL 2700k

Temps; Day, 78 Night: 75

Humidity; Day, Night: Na

Ventilation System; Yes, small fans & charcoal filter in Gorilla tent Size 6" charcoal filter

Ac, Humidifier, De-humidifier, na

Co2; Yes, No: no

Everything was fine until 21 days into flower. Problem began with yellowing of tips of a couple top leaves. Problem has only progressed. Yesterday 34 days into flower I had one CFL a little low to top of flower which is where discoloration was predominate as seen in pic above

Yes I think we understand it’s a deficiency of some sort but the underlying reason is because of his pH fluctuations

pH aside for now, It’s not getting enough food, will catch up later, I’m on the road right now


All of here are here to help each other out the best we can.
and we will get to the bottom of it !



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why isn’t this applicable? a low humidity and high night temps would certainly have me concerned unless lights are on she doesn’t pull water up in temps of 78-75 she’s got to be drinking like crazy I would be really wondering if she isn’t?
Are you able to bring down your night time temps and tell us humidity? it is a huge factor because your plants look wilted but dry and crisp at tops which is where it should be hottest also where are your circulation fans are pointed at your ladies or the light a constant breeze would further draw moisture from your leaves

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Light burn is often mistaken for a Nitrogen deficiency which makes wilting yellow leaves. Nitrogen deficient leaves fall off on their own, while light burned leaves are hard to pluck off. A nitrogen deficiency starts from the bottom of the plant and moves up, while light burn often is worse at the top of the plant.
Cannabis light burn usually affects the top leaves closest to the grow light

A Nitrogen deficiency creates yellow leaves at the bottom of the plant as the Nitrogen is sucked out of the oldest leaves to feed the top of the plant. On the other hand, light burn produces yellow leaves at the top of the plant under the grow lights because the leaves have worked too hard and/or too long from the light being too close. The leaves aren’t able to keep up with regular plant processes.
Imagine sitting outside all day under a scorching sun, possibly for days on end. Even if you could handle it for a day or two, it might wear you down over days or weeks.
How can there be too much light if there’s no heat? Read the full guide
It’s probably light burn if mostly just the leaves closest to the lights are turning yellow

With cannabis plants that have light burn, your leaves can become yellow or red/purple, possibly with brown spotting, often with burnt tips/edges and margins that stay green. Other problems, like nutrient problems, can trigger or make the symptoms of light burn a lot worse. Leaves may also appear generally burnt in places when there’s too much light, especially when combined with heat or nutrient problems.
If you see light bleaching and unhealthy discoloration only on the parts of the plant directly under your grow light, or only on older leaves that are exposed to the light, it often means it’s too bright for your plants and you should move your grow lights further away! If your plant is also having other problems, it is much more likely to be affected by light burn. A healthy plant can withstand higher light levels than a sick plant.
With light burn, often the inside veins stay green. Yellow leaves won’t fall off or be plucked off easily, unlike a nitrogen deficiency where leaves fall off on their own.



This post is why I think he’s having issues I don’t know what he’s trying to do with this pH, but I suspect it’s causing some type of a lock out and that’s what we are seeing in the pics

I’m trying to get his pH issues squared away I use ffof I’m out now but I would recommend he flush with a 6-5 heavy and leave it alone for a while and then a balanced program of newts

I’ll check back later but that’s what I’m understanding he saying will


Ok then…he should do a complete flush and move his lights up.
cut the bad leaves off because they won’t recover anyway and will help the plant to recover faster.
if that fails which it shouldn’t we’ll have to go to plan 3


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That’s what I’m seeing too, also @Jpositive needs to read Roberts grow Bible on pH

After a good flush with 6.5 leave it alone and then start feeding it at 6.5 and use a balanced three-part formula like gh, Fox Farms or whatever but you gotta feed more than you’re using, and it is not balanced, which I feel is probably part of problem too

…and next time you want to check your run off ask yourself why first, because you don’t have to check it all the time, on healthy plants I very likely never check it during their whole cycle

I use Farm ocean Forest so hit me up if you need some more info hope this helps

What? is this a hydro or soil grow? I see no clarification. You certainly do not want to raise PH that high for hydro…

You should be able to place CFL lamps inches away from canopy without issue. However; CFL users seem to have issues because the bulbs only cover so much area.

It means he does not check or control RH.

Now…I agree with Oak. PH was way too acidic. You should be running 6.5-7.0 PH. Never below 6.5 in soil. So; a nutrient issue could be the problem. How many ppm is the flower power after you mix a gallon? That is the question.

You should not need to shutoff one tiny little CFL. These 3 lamps are not your issue. You may have caused light burn from having a lamp too close but, you should not turn it off! You barely have enough light to survive a full grow.

I think all you need to do is make sure your solution/water is PH above 6.5 and watch new growth to monitor health for the next few days.

How is your drainage? I was having similar problems. Mines was ph issue. I never checked my ph and my plant miraculously did well or ok for the first 4 to 5 weeks then she just stopped growing and was turning yellow and no matter what I did nothing was helping then I did what @yoshi told me to do. A few drain holes for better drainage and ph water 6.3 and and the next day I bought a ph meter
and a up and down ph solution and let me tell you my ph was out of wack by a long shot but thanks to @yoshi my baby is doing a lot better. Just feed her ph water at around 6.3 with atleast 30% run off and test your run off ph . should be in the 5.8 range. Do not feed her anything till her ph is in a good rrang. Water her only when the soil is a little moist but not wet hard to explain. this way you get more oxygen in to the roots
I hope this helps

I meant unknown. I don’t know what the humidity is.

Only the very top leaves are having any discoloration. Everything below is nice and green. No yellow.
Here again is a close-up of the left side of the plant where I left one cfl about an inch and a half from top of flower.

Soil. Fox farm ocean forest.