Always going yellow and dropping leaves mid flower!

Hi Everyone,

My plants are always in perfect health until about week 4 of flower when I start to notice some leaves dropping and yellowing. The last grow I did I had to take one down early because even the sugar leaves around the buds were brown and crunchy.

This grow I am starting to see the same thing with my chocolope really bad and my Girl Scout cookies seems to just be effected on the lower fan leaves.

I am growing in fabric pots in coco under a 315CMH and a 140 actual watts LED.

I am watering when the top layer of coco is dry and allowing about 30% run off. I PH my nutes at about 6-6.3 and use nutes every water at half strength.

Temps are running at 75F which I know is a bit hot and humidity is around 60-65.

I am giving them just flowering nutes (local company makes them and all the commercial growers here use them) and silicate (mostly to balance PH). I usually give half flower nutes and half veg nutes for the first 1.5 weeks of flower but maybe this is too short?

thanks for any help! It is frustrating because I always feel like I have to chop before they are truly done!

Nutes I am using in flower.

YouTube - Jorge Cervantes Yellowing Leaves
It can use nitrogen but it's your choice.

xtraLRG420 said:

YouTube - Jorge Cervantes Yellowing Leaves
It can use nitrogen but it's your choice.

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do you think I should be giving veg nutes longer into flower?

would I just give veg nutes for a feeding now to help?

thanks!!

Looks like you are starving them

Herb & Suds said:

Looks like you are starving them

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any suggestions?

BCBudNerd said:

do you think I should be giving veg nutes longer into flower?

would I just give veg nutes for a feeding now to help?

thanks!!

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I'm only 1 week into my first flowering cycle so I can't tell you from experience. I can only tell you what I plan to do based on research, which is to keep it green until the last two weeks when I'm gonna flush the soil and have the buds purposely feed from the leaves. If I were you I would give a light feeding of nitrogen. The Tiger Bloom I'm using has a little bit of nitrogen with an NPK of 2-8-4 so I'm guessing that's gonna be enough.

BCBudNerd said:

any suggestions?

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Are you giving them cal/mag yet?

or does your water contain some already?

Nutty sKunK said:

Are you giving them cal/mag yet?

or does your water contain some already?

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I soak the coco in cal mag at full strength before starting my grow and give cal mag at 1/2 strength until second week of flower. My water does contain a small amount of both minerals.

BCBudNerd said:

I soak the coco in cal mag at full strength before starting my grow and give cal mag at 1/2 strength until second week of flower. My water does contain a small amount of both minerals.

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Reason being is that cal/mag contains nitrogen. So you can supplement some this way.

I’ve heard too much P too early can cause premature yellowing.

And yeah they use a ton of nitrogen during stretch and even first couple of weeks.

so veg nutes until 3rd week then go 50:50 veg and bloom depending on genetics. If a long flower keep the veg nutes longer...

Nutty sKunK said:

Reason being is that cal/mag contains nitrogen. So you can supplement some this way.

I’ve heard too much P too early can cause premature yellowing.

And yeah they use a ton of nitrogen during stretch and even first couple of weeks.

so veg nutes until 3rd week then go 50:50 veg and bloom depending on genetics. If a long flower keep the veg nutes longer...

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thanks for the advice! Would it be bad to give it 50:50 veg/flower for a feeding to try to supplement some nitrogen or just give cal mag?

BCBudNerd said:

thanks for the advice! Would it be bad to give it 50:50 veg/flower for a feeding to try to supplement some nitrogen or just give cal mag?

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Actually what I’m seeing is yellowing from the top down?

N goes bottom to top.

you say this has happened before?

How is your humidity/light distance?

BCBudNerd said:

The last grow I did I had to take one down early because even the sugar leaves around the buds were brown and crunchy.

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Classic sign of toxic salts buildup. Feeding too heavy for too long. Starts around the middle of flower and can begin in top leaves first if the lights are hot but generally starts in lower fan leaves first. Thick, crunchy leaves that go yellow/brown all over in blotches.

I get that easy here because of low RH causing the plants to pull up more nutes than they can process with all the extra water they drink so it gets stored in the leaves until it becomes toxic. Flushing some water thru will slow the process but not cure it.

What's your water like as minerals in tap water will make it worse.

OldMedUser said:

Classic sign of toxic salts buildup. Feeding too heavy for too long. Starts around the middle of flower and can begin in top leaves first if the lights are hot but generally starts in lower fan leaves first. Thick, crunchy leaves that go yellow/brown all over in blotches.

I get that easy here because of low RH causing the plants to pull up more nutes than they can process with all the extra water they drink so it gets stored in the leaves until it becomes toxic. Flushing some water thru will slow the process but not cure it.

What's your water like as minerals in tap water will make it worse.

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he may be right. a quick way to check would be to check your runoff ph and/or ec. since you're in coco, that would be where I would start. if you dont have an ec, ppm, tds meter, you should at least get yourself a cheap one.

Usually if its overfertilized the leaves will claw down.. Yours aren't doing that.


Its also a MYTH/FAKE NEWS to cut NITROGEN during flowering. Marijuana needs an increasing amount of ALL NUTRIENTS UNTIL WEEK 6 IN AN 8 WEEKS FLOWEIRING STRAIN. NITROGEN INCLUDED.

Nitrogen to a Plant is THE SAME EXAACTLY as Protein is for a human being. We eat Protein, and our bodies turn it into Nitrogen.
Magnesium is the #1 container grown plant deficiency, and add in weed is a huge consumer of Mg. One of the biggest consumers of mg there is.

IMHO it looks Mg starved.

Also 75f is NOT to hot. I myself like temps from 78f-82f, as long as there is good airflow. If temps get to low this will cause the plant to use less food, and water, and if fed full strength is a recipe for nutrient burn. I also don't like temps under 72f at night. also need strong airflow when lights are out.
Plants use , and give off CO2 when lights out/Respire, and Transpire when Lights Out. Take in CO2, and give off Oxygen.

IN an 8 weeks flowering strain, plants need an ever increasing need for ALL NUTRIENTS.

At 2.5 weeks- week 4 they need a 0-52-34-Monopotassium Phosphate BOOST.

In weeks 5-6 they need a Magnesium/Sulfur boost. Mg/sulfur are crucial for terpene production.

Weeks 7-8 need less of everything, but never starved.

They're drying out too much, and pulling nutrients from leaves..

Why aren't you feeding full strength?
I use cal-mag and feed full strength every watering in coco.

Don't you love all the consistent answers . I honestly wouldn't worry too much about it for this crop unless it's being agressive. But it would be good to know for future grows. I would check your runoff ph and ec (if you have an ec meter). It could quickly point you to what's wrong. Most coco growers with issues dont allow for enough runoff each watering and end up getting locked out from build up of salts.