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What causes yellow, curling leaves? Some are dying. Started after 12/12

4

420peace

New member
Frustrated a bit. I'm using General Hydroponics nutrients using half strength what's on the bottle. I'm watering plants and giving nutrients every watering. They're in coco so I'm trying to give them 6 ph. But it's so hard knowing what the pH is using the kit with the drops. I feel like I can never tell what color the water is compared to the chart.

The plants were healthy in the vegetative stage. I thought I had the hang of everything. Oh overconfident me.

The problem seems to have started since I switched to 12/12. The buds started forming but the leaves started dying at the same time.

I see lots of symptoms. Some leaves are turning brown and dying. Especially the lower ones. I'm also seeing what looks like nutrient burn, which makes me think it's not that they need more nutrients overall. Some of the leaves are curling, which makes me think it might be over watering, but in general the plant doesn't seem particularly droopy. I also noticed the edges of the leaves look stressed on some of the leaves.

The temperature is a little warm but not hot, around 80F in the day and 73F at night. 50% humidity.

What could be causing this?

Yellowing cannabis plant with dying leaves :(
 
Where on the plant did the yellow leaves first appear? Did it start low and move up? How far into flower R U? It looks a little crowded. I see some leaf tacoing. How close to the canopy is your light? Are you running circulation fans? Are they blowing directly on the canopy?

Will your budget allow you to buy a PH pen?
 
I agree with the tacoing also the shark tooth leaf edges, I would start by pulling your light back from the plant and or dimming it. Too much light can cause all kinds of problems as more light pushes the plant harder. This can result in deficiencies as well as light stress symptoms due to the plant trying to use all that light without enough or proper nutrition. It’s all a balance keep working on it.
Once the plant moves to flower it get more picky, most of us have experienced success in veg only to have problems come in the flower stage. Very common.
Temp and humidity seem fine
 
golfnrl said:
Where on the plant did the yellow leaves first appear? Did it start low and move up? How far into flower R U? It looks a little crowded. I see some leaf tacoing. How close to the canopy is your light? Are you running circulation fans? Are they blowing directly on the canopy?

Will your budget allow you to buy a PH pen?
Click to expand...
I started noticing a few leaves here and there looking not perfectly green a week or two ago. I noticed it on the top leaves first but now it's the power leaves that look worse.

We're 3 or 4 weeks since 12/12, so quite a way to go. All the hairs are still white.

I wonder if the LED might be too close. It's 100W, about 10 inches away. It does seem like the symptoms might be worst right under the light, but I'm noticing symptoms even on the leaves far from the light so I'm not sure.

I do have a small fan blowing air around.

I think I need to get a PH Pen. I'm so over using the drops! Even if I have multiple problems, I'm pretty sure ph is one of them.
 
Smallgrow said:
I agree with the tacoing also the shark tooth leaf edges, I would start by pulling your light back from the plant and or dimming it. Too much light can cause all kinds of problems as more light pushes the plant harder. This can result in deficiencies as well as light stress symptoms due to the plant trying to use all that light without enough or proper nutrition. It’s all a balance keep working on it.
Once the plant moves to flower it get more picky, most of us have experienced success in veg only to have problems come in the flower stage. Very common.
Temp and humidity seem fine
Click to expand...
Yeah, it does seem worse right under the grow light, though I'm seeing symptoms on lower leaves too.

That's good to know about cannabis plants getting more picky in the flowering stage. It really felt like that. Everything looked so healthy in the vegetative stage!
 
Ckbrew said:
I see a bunch of things. The taco leaves show to much heat/light. They need a good defol. Are you using a calmag supplement? To check pH on the cheap I use these: https://www.amazon.com/dp/B0D7TRQCMM?ref_=ppx_hzsearch_conn_dt_b_fed_asin_title_1
Many people like the pH pens, imo they are not worth the hassle and expense. How is the air circulation?
Click to expand...
I think the led might be too close. It's 100W, about 10 inches away. I'm not using Calmag. I have a small fan blowing air around.

Just curious, do you use the General Hydroponics ph test kit with drops, or how do you test the ph?
 
The best way to test ph is with a good quality PH pen like Apera or BlueLabs. But they are not cheap and do require calibration and maintenance . Don’t get the cheap ones they are unreliable in my opinion.
As @Ckbrew said There are also paper test strips that some people use with success similar to the liquid test you have to compare the colours to the chart.
What light are you using and are you in a tent ?

Sounds like you should read through the main GWE site were happy to answer question but everything you need is likely there, maybe start here
www.growweedeasy.com

Learn How to Grow Cannabis Indoors | Grow Weed Easy

This easy tutorial explains how to grow cannabis indoors from seed to harvest. Learn how to take care of your plants with step-by-step instructions!
www.growweedeasy.com www.growweedeasy.com
And at the top of that page there will be a pull down menu titled “Start Here” read the rest of those pages as well to get the basics
 
420peace said:
I think the led might be too close. It's 100W, about 10 inches away. I'm not using Calmag. I have a small fan blowing air around.

Just curious, do you use the General Hydroponics ph test kit with drops, or how do you test the ph?
Click to expand...
Your light is to close. Calmag is essential for growing in coco. It needs it. I use the pH strips I showed you. Many people will disagree with me on this but take it from a retired lab rat, pH pens are a royal PITA and are not needed for growing. Strips or papers are adequate for this job and much easier.
 
I think Ckbrew and Chipmunk's suggestion of pH test strips is a good idea for smaller grows. Simple, sound advice from guys who know their way around a lab!

Personally, I use a cheap $20 Vivosun pH pen. Yes, I have to calibrate it occasionally, and they do break (back up is pH strips). But, I often mix 6 x 6.5 gallon buckets of nutrients and pH'd water at a time. Using a pen goes faster and easier for my situation. BTW, I only calibrate it to one decimal place, greater accuracy not needed.
 
I don't calibrate my pen that much. When in question I just read some fresh standards. The ones you use to calibrate with. It's kind of like using a control. If the standard reads an acceptable number for you then no need to calibrate. Don't need to fix what aint broke
 
I started off with a Hannah Instruments PH pen. It lasted a couple of years. I switched to BlueLab and have had the same pen about 4-5 years. I calibrate it about once a month. That takes about 5 minutes.

Amen on the Cal/Mag for coco. Supplement every feed. The correct PH range is always important. I read somewhere recently that improper PH is the #1 cause of MJ growing issues. I believe it.
 
420peace said:
I started noticing a few leaves here and there looking not perfectly green a week or two ago. I noticed it on the top leaves first but now it's the power leaves that look worse.

We're 3 or 4 weeks since 12/12, so quite a way to go. All the hairs are still white.

I wonder if the LED might be too close. It's 100W, about 10 inches away. It does seem like the symptoms might be worst right under the light, but I'm noticing symptoms even on the leaves far from the light so I'm not sure.

I do have a small fan blowing air around.

I think I need to get a PH Pen. I'm so over using the drops! Even if I have multiple problems, I'm pretty sure ph is one of them.
Click to expand...
OK. Since the yellowing leaves did not start at the bottom of the plant and move up, you are not dealing with a mobile nutrient issue. I'm leaning toward light/heat stress. Raise the light to the manufacturers recommendations for the flower stage. Or raise it to 18" above the canopy and watch your plants for a couple of days. If you can clean out the middle of your plant that will help with circulation.
 
Ckbrew said:
Your light is to close. Calmag is essential for growing in coco. It needs it. I use the pH strips I showed you. Many people will disagree with me on this but take it from a retired lab rat, pH pens are a royal PITA and are not needed for growing. Strips or papers are adequate for this job and much easier.
Click to expand...
I defiantly agree they are a PITA and somewhat costly.
 
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