Potassium deficiency right?

[Sangmang]

I end up with these symptoms every grow no matter the strain and with different nutrients. At first I blamed it on overfeeding Nitrogen but this current grow i really backed off the N after stretch and its still showing. Currently using Megacrop 2 part and Bud Explosion in 3 gal coco hand feeding to run off once daily. Usually maxed around 700-800ppm and 6ish PH.

Around mid to late flower this starts to show

And by the end of the grow I end up with clawed crispy top leaves and even the top bud seems dried out and kinda crunchy. The sugar leaves even show some issues.

I know these pics show N excess. This current grow I completely cut out the part B(Nitrogen) by mid flower because it seemed I was heading towards N tox again. But same looking K deficiency showing. I tried upping my Bud Explosion dose(P&K) but same result.

 

[Buds Buddy]

I end up with these symptoms every grow no matter the strain and with different nutrients. At first I blamed it on overfeeding Nitrogen but this current grow i really backed off the N after stretch and its still showing. Currently using Megacrop 2 part and Bud Explosion in 3 gal coco hand feeding to run off once daily. Usually maxed around 700-800ppm and 6ish PH.

Around mid to late flower this starts to show

And by the end of the grow I end up with clawed crispy top leaves and even the top bud seems dried out and kinda crunchy. The sugar leaves even show some issues.

I know these pics show N excess. This current grow I completely cut out the part B(Nitrogen) by mid flower because it seemed I was heading towards N tox again. But same looking K deficiency showing. I tried upping my Bud Explosion dose(P&K) but same result.

You said the pH was 6ish. If you are growing in Coco your pH should be 5.8. You have to start at the low pH end because the pH climbs on it's own. Without starting at 5.8 you are not taking up all of the nutrients because different nutes are taken up at different pH levels.
Do you feed every time ? No straight water in Coco unless you are Flushing out a toxicity.
Do you keep the Coco moist (not wet) at all times ? Not suppose to let Coco dry out ever.
I'm thinking the Coco pH is off now from not pH-ing to 5.8 & you will need to flush & then feed with the correct pH nutes to fix this.
Do you add CalMag ? Coco is a CalMag whore. Especially in Flower with LED lighting. I had to add 2-3 ml. of CalMag every feed to prevent def's.

 

[cjsbabygirl313]

You said the pH was 6ish. If you are growing in Coco your pH should be 5.8. You have to start at the low pH end because the pH climbs on it's own. Without starting at 5.8 you are not taking up all of the nutrients because different nutes are taken up at different pH levels.
Do you feed every time ? No straight water in Coco unless you are Flushing out a toxicity.
Do you keep the Coco moist (not wet) at all times ? Not suppose to let Coco dry out ever.
I'm thinking the Coco pH is off now from not pH-ing to 5.8 & you will need to flush & then feed with the correct pH nutes to fix this.
Do you add CalMag ? Coco is a CalMag whore. Especially in Flower with LED lighting. I had to add 2-3 ml. of CalMag every feed to prevent def's.

I actually read the same thing recently: that LEDs cause plants to require more CalMag than normal. So if Coco does it and LEDs do it, I would definitely say yeah, add *additional* CalMag!

 

[Buds Buddy]

I actually read the same thing recently: that LEDs cause plants to require more CalMag than normal. So if Coco does it and LEDs do it, I would definitely say yeah, add *additional* CalMag!

Coco doesn't have any nutrients at all in it. That's why it takes more CalMag then soil would. Plants tend to need a little more during Flower anyway for most strains.

 

[cjsbabygirl313]

Coco doesn't have any nutrients at all in it. That's why it takes more CalMag then soil would. Plants tend to need a little more during Flower anyway for most strains.

My last grow (my first), was aMephisto Genetics Hubbabubbasmelloescope that was a CalMag whore. I was convinced she had a CalMag issue but my mentors kept telling me ”no, not calmag issue’” and advised me not to add more. I went with my gut, upped her CalMag by 50% above recommendation on bottle and her problems stopped

 

[SmokingWings]

I know these pics show N excess. This current grow I completely cut out the part B(Nitrogen) by mid flower because it seemed I was heading towards N tox again. But same looking K deficiency showing. I tried upping my Bud Explosion dose(P&K) but same result.

Looking good except for that pesky yellow in the margins of the fingers.

I grow in soil and I had similar problems. My excess Nitrogen problem went away when I started to cut the Nitrogen by mid to late in the vegetating stage and not waiting till flowering. There seems to be enough N still available in the soil to carry through to harvest. The few times I noticed any yellowing in the leaves by mid-flowering that seemed to be caused by low N availability I would water with a mild fish emulsion. Usually one time was enough to slow down or stop it. It helped but did not make the N problem go completely away. The plants still need some N and since you are in coco maybe think about reducing the amounts of your 'Part B' earlier but not cut it out completely.

Again, I am in soil so you might not be able to do it the same way but with a bit of experimenting you might be able to come up with something that works for your grow style. I start to give a dose of Phosphorus (P) about 2 weeks before I will be putting the plant into the flowering tent. Then another dose a week after going in the flowering tent or about the time the pistils start to show.

That does look like a mild Potassium shortage. I have started giving a 'normal' dose of K every 7-10 days . The Potassium is great for plant health and vigor. Maybe there is source of K that is available without adding more of something like the P or N that you do not want at the moment.

Maybe trying something similar will help with your grow.

 

[Buds Buddy]

Looking good except for that pesky yellow in the margins of the fingers.

I grow in soil and I had similar problems. My excess Nitrogen problem went away when I started to cut the Nitrogen by mid to late in the vegetating stage and not waiting till flowering. There seems to be enough N still available in the soil to carry through to harvest. The few times I noticed any yellowing in the leaves by mid-flowering that seemed to be caused by low N availability I would water with a mild fish emulsion. Usually one time was enough to slow down or stop it. It helped but did not make the N problem go completely away. The plants still need some N and since you are in coco maybe think about reducing the amounts of your 'Part B' earlier but not cut it out completely.

Again, I am in soil so you might not be able to do it the same way but with a bit of experimenting you might be able to come up with something that works for your grow style. I start to give a dose of Phosphorus (P) about 2 weeks before I will be putting the plant into the flowering tent. Then another dose a week after going in the flowering tent or about the time the pistils start to show.

That does look like a mild Potassium shortage. I have started giving a 'normal' dose of K every 7-10 days . The Potassium is great for plant health and vigor. Maybe there is source of K that is available without adding more of something like the P or N that you do not want at the moment.

Maybe trying something similar will help with your grow.

Terpenator is 0-0-4.

 

[Roy Growin]

Terpenator is 0-0-4.

Slightly different reason, but that worked for Copperein as a dose of just K

 

[Sangmang]

You said the pH was 6ish. If you are growing in Coco your pH should be 5.8. You have to start at the low pH end because the pH climbs on it's own. Without starting at 5.8 you are not taking up all of the nutrients because different nutes are taken up at different pH levels.
Do you feed every time ? No straight water in Coco unless you are Flushing out a toxicity.
Do you keep the Coco moist (not wet) at all times ? Not suppose to let Coco dry out ever.
I'm thinking the Coco pH is off now from not pH-ing to 5.8 & you will need to flush & then feed with the correct pH nutes to fix this.
Do you add CalMag ? Coco is a CalMag whore. Especially in Flower with LED lighting. I had to add 2-3 ml. of CalMag every feed to prevent def's.

So I usually aim for 5.8 but since I'm mixing nutes every watering I like to vary it between 5.8-6.3ish. Or are you saying the ph of the coco will raise on its own throughout the grow?
Yes, nutrients every watering, and I water at least once a day, never dry coco.
Yeah I got bad Cal def my first grow so I give a full dose from time to time. I don't like adding it every watering though because MC has a good amount of Cal & Mag. Thanks for your input!

 

[Sangmang]

Thanks for all the advice. I'm kind of leaning towards the issue being related to N tox still even though I sorted it out a bit. I'll try tapering off N before flower maybe. Also I'll be more strict about my PH'ing. I would definitely like to find some seperate powders for N,P&K to have on hand.

 

[Buds Buddy]

Not sure what powder brands are out there. I use Natures Nectar Nitrogen, but it's liquid. I used the MC All in One plus I added MSA Stout Silica, Nitrogen & a little CalMag. Best grow I ever had. I've never tried the 2 part so don't know much about it.

 

[Buds Buddy]

So I usually aim for 5.8 but since I'm mixing nutes every watering I like to vary it between 5.8-6.3ish. Or are you saying the ph of the coco will raise on its own throughout the grow?
Yes, nutrients every watering, and I water at least once a day, never dry coco.
Yeah I got bad Cal def my first grow so I give a full dose from time to time. I don't like adding it every watering though because MC has a good amount of Cal & Mag. Thanks for your input!

What I'm saying about the pH is... If you mix a gal. of nutes & pH it to 5.8 today, then let those nutes sit for 1 day & check the pH it will probably be up to 6.0 pH by then. The next day 6.2 pH. The pH climbs for some reason. I don't know the why of it... but it does. Since there's no Buffers to adjust pH in Coco you have to do the work & pH to the lower end of the pH scale since the pH will climb. That's also why it's important to feed till you get 10% run off in Coco. It Flushes out the Salt Build Up of the nutes which will over time change the pH of the Coco if you don't. Coco grows are real similar to Hydro grows. Things have to be more precise to prevent issues.

 

[bobrown14]

I actually read the same thing recently: that LEDs cause plants to require more CalMag than normal. So if Coco does it and LEDs do it, I would definitely say yeah, add *additional* CalMag!

Dont believe what you read without doing due diligence. I've grown with LED for the last 10 years. Tossed my first cal/mag bottle in the compost pile and never used the stuff.

Looks to me like your plants want to go into senescence but you're feeding them enough that it stops that natural process. At some point maybe try cutting back on feeds say the last 2-3 weeks and see if you leaves dont actually start turning fall colors.

That process is good for flowers and specially flavor. Green all the way to the end = harsh tasting for me. I like colors and not green at chop.

Great job tho - a little burnt tips I consider perfect but thats me.

 

[Sangmang]

Dont believe what you read without doing due diligence. I've grown with LED for the last 10 years. Tossed my first cal/mag bottle in the compost pile and never used the stuff.

Looks to me like your plants want to go into senescence but you're feeding them enough that it stops that natural process. At some point maybe try cutting back on feeds say the last 2-3 weeks and see if you leaves dont actually start turning fall colors.

That process is good for flowers and specially flavor. Green all the way to the end = harsh tasting for me. I like colors and not green at chop.

Great job tho - a little burnt tips I consider perfect but thats me.

Thank you. Yes I agree about the calcium hype. I stopped using it myself too. I might give them a few good doses per grow to be safe but megacrop has plenty of calcium and as I understand the plant is good at utilizing it. I like what you're saying about senescence. I'll try cutting back more than I usually do. How light do you feed at the end? Ive been feeding about 700-800 ppm of my base nutrients most of flower.

 

[bobrown14]

Organic soil grower - no-till so use soil over and over water only. Amend with a few organic amendments at up-can going into flower is all I do then water only. Can go about 5 years same soil without issues. That's like 15-20 flower runs.

I add Silica in my IPM weekly. Plants need a lot of Calcium but not very much Magnesium.

I just make sure there's enough short and long term release Ca in my soil mix there will for sure be enough Mg already in there from compost/ewc inputs.

 

[SmokingWings]

What I'm saying about the pH is... If you mix a gal. of nutes & pH it to 5.8 today, then let those nutes sit for 1 day & check the pH it will probably be up to 6.0 pH by then. The next day 6.2 pH. The pH climbs for some reason. I don't know the why of it... but it does

I had looked up info on the water pH changing in regards to tropical fish hobbyists letting buckets sit out. If I am remembering right it was the air, especially the carbon-dioxide, having an influence on the carbonic acid (H2CO3) in the water. More carbon dioxide in the air the more likely the water pH will drop over several days.

Then to make it more complex the temperature of the air seems to influence how fast the pH of the water changes. Warmer air seems to speed up the break down of the carbonic acid and the water will be less acid and the pH rises.

 

[bobrown14]

Dont forget there are microbes at work also. They can affect the pH of the solution.

Microbes that live in the water/fertilizer solution are anaerobic and can contribute to lowering the pH. Just putting that out there.

 

[Buds Buddy]

Interesting stuff about how pH lowers & raises. I've never had it lower though. I mix 10 gal. of nutes at a time. 2 - 5 gal. buckets. Lasts for 2 feedings. I pH to 6.3. In 2-3 days the pH will be back up to 6.7 every time. Never had the pH go down in 4 years of growing. I'm not sure what happens with the pH with just water & no nutes added. Never checked as I never feed just water.

 

[cjsbabygirl313]

Interesting stuff about how pH lowers & raises. I've never had it lower though. I mix 10 gal. of nutes at a time. 2 - 5 gal. buckets. Lasts for 2 feedings. I pH to 6.3. In 2-3 days the pH will be back up to 6.7 every time. Never had the pH go down in 4 years of growing. I'm not sure what happens with the pH with just water & no nutes added. Never checked as I never feed just water.

I can answer that one - even plain water that has been ph’d DOWN will rise over time if not sealed air tight. How do I know? Because I have been running plain water through my DWC buckets for the last week or so to monitor average tent temps and RH and to watch what the ph does. Been taking readings every day. I’ll drop the ph down to about 5.5 and the next day its back up to 6.2 or so. I’ll adjust it again and sure enough 24 hours later, its back up there. I have also noticed it does not seem to climb above 6.7 or so though.

It was explained to me that the ions are whats changing because of expose to air - and it sure seems to be the case!

 

[bobrown14]

Just a little side note about pH and nutrient uptake. With a lower pH heavy metals are more mobile and can be taken in by plants. For home growers its not really an issue but heavy metals are tested for in professional grows.

I like to see my pH up above 6.7pH for that reason.

I don't really mess with my soil pH but I do test my RO water every time I fill the reservoir. I'll keep my water pH around 6.7pH - 7pH. I never get lockouts. Knock woody.

We have high alkalinity so its tough to keep pH in check on our well water.