6 Weeks Into Flower ... What's Wrong???

My plants have been growing healthy until just a few days ago when one of them (only 1 plant) has a bunch of leaves that have turned yellow or brown, doesn't look pretty. Pics attached.

Anyone know what this is? how to counter it? will my plant survive til 9 weeks to harvest?

75/25 Coco/perlite, Canna Coco A, B, Rhizotonic, Cannazym, Boost, Bud Candy, PK13/14.
EC 2.1 last feed (they received PK13/14 for week 5 only, no more PK13/14 now), pH 6.0 in a 2x4x5 tent with 400W HPS and they have all looked great until now, in fact they still do it's just this one plant right now.

EC was 2.1? What brand meter are you using?

hotrodharley said:

EC was 2.1? What brand meter are you using?

Click to expand...

Bluelabs (truncheon) and yes it was 2.1 (aka 1050ppm), I will go to EC 2.2 (1100ppm) but no higher. I am following the exact feeding schedule that Canna has suggested too.

guitarguy10 said:

Bluelabs and yes it was 2.1 (aka 1050ppm), I will go to EC 2.2 (1100ppm) but no higher.

Click to expand...

I suggest rolling it back actually. To about 1.8 max.

hotrodharley said:

I suggest rolling it back actually. To about 1.8 max.

Click to expand...

I will be rolling it back now that they are past week 5 (and past their PK13/14 feedings, it was the addition of PK13/14 that made the EC higher).

In any event, why is that plant dying, or very ill? That's what I'm worried about.

guitarguy10 said:

I will be rolling it back now that they are past week 5 (and past their PK13/14 feedings, it was the addition of PK13/14 that made the EC higher).

In any event, why is that plant dying, or very ill? That's what I'm worried about.

Click to expand...

I’m suspecting nute burn or excess.

agree with hotrod roll back on nutes!!

This is the feeding schedule I was using. I will try backing off of nutes thanks.

GG,
My first coco grow at my new location did that. I was not getting enough runoff and had toxic nutrient salt build up.

You need to give them a good flush...then resume and go for more runoff.
JD

These have been grown with Dutch pro nutrients no higher than 1.2EC

I’m about to back off again to around 1.0 next feeding. They’re receiving only A and B along with a minimal amount of PK13/14

These are at day 25 of 12/12 around day 18 of flowering.

If I followed the DUTCH PRO feeding schedule these would be receiving around EC2.6 right now.

JohnDee said:

GG,
My first coco grow at my new location did that. I was not getting enough runoff and had toxic nutrient salt build up.

You need to give them a good flush...then resume and go for more runoff.
JD

Click to expand...

My advice as a coco grower (I use 100% coco no cutting it!) would be to feed next time at your planned level and see what your runoff tests for EC. when I feed with 1.0-1.2 that’s what comes out when my runoff is tested! Virtually no change in EC.

I bet your truncheon flashes at its highest reading when you test yours.


Having used canna coco nutes before I can tell you from experience the only things of canna you are best using are A/B ZYM and the rhizotonic during early veg, PK13/14 very lightly at about 0.5ml per litre from around week 3 of flowering. As PK13/14 is increasing your EC I recommend lowering the amount of base nutes to keep your EC under 1.4 for the entire flowering period.

Right now your best cause of action is to back off to around 1.8 next feed. Then possibly 1.6 the feed after that.

Your rootzone is in salt build up shock right now.

Imo you should not FLUSH copious amounts of water through coco without it containing some nutrients.

Your rootzone EC can be brought down that way to 1.8EC quite quickly by feeding with around 3x the amount of feed, that your pot can hold of coco. 20L pot feed 60L if feed through the rootzone to stabilise the CEC within your roots.

jondamon said:

Imo you should not FLUSH copious amounts of water through coco without it containing some nutrients.

Your rootzone is in salt build up shock right now.
.

Click to expand...

Excellent post Jondy...I think my post was assumed to be the generic "flush" post...but in this instance, that's exactly what he needs. Nothing else will do.
Cheers,
JD

GuitarGuy,
I tried to minmimize runoff by keeping my nutes really low. I was trying to avoid runoff because it's such a damn hassle. I'm now using trays, tilted just a bit, with drain hoses out the bottom. Still leaves a bit of water to mop up.

When I experienced this problem last winter...it occurred at around the same time. Latter part of flower. Demands go up ans it just takes awhile for the salts to accumulate.

Hey, if you flush...and I really feel you should, just be careful to not use straight water. 1/4 strength nutes or calmag so you don't wash out the calmag buffering of your coco.
JD

JohnDee said:

GuitarGuy,
I tried to minmimize runoff by keeping my nutes really low. I was trying to avoid runoff because it's such a damn hassle. I'm now using trays, tilted just a bit, with drain hoses out the bottom. Still leaves a bit of water to mop up.

When I experienced this problem last winter...it occurred at around the same time. Latter part of flower. Demands go up ans it just takes awhile for the salts to accumulate.

Hey, if you flush...and I really feel you should, just be careful to not use straight water. 1/4 strength nutes or calmag so you don't wash out the calmag buffering of your coco.
JD

Click to expand...

My sentiments exactly.

My post wasn’t intended to bash your advice if that’s how it was taken?
More to expand on a great recommendation already.

jondamon said:

My advice as a coco grower (I use 100% coco no cutting it!) would be to feed next time at your planned level and see what your runoff tests for EC. when I feed with 1.0-1.2 that’s what comes out when my runoff is tested! Virtually no change in EC.

I bet your truncheon flashes at its highest reading when you test yours.


Having used canna coco nutes before I can tell you from experience the only things of canna you are best using are A/B ZYM and the rhizotonic during early veg, PK13/14 very lightly at about 0.5ml per litre from around week 3 of flowering. As PK13/14 is increasing your EC I recommend lowering the amount of base nutes to keep your EC under 1.4 for the entire flowering period.

Right now your best cause of action is to back off to around 1.8 next feed. Then possibly 1.6 the feed after that.

Your rootzone is in salt build up shock right now.

Imo you should not FLUSH copious amounts of water through coco without it containing some nutrients.

Your rootzone EC can be brought down that way to 1.8EC quite quickly by feeding with around 3x the amount of feed, that your pot can hold of coco. 20L pot feed 60L if feed through the rootzone to stabilise the CEC within your roots.

Click to expand...

Yeah, even though I am using their feeding chart I have had to make some changes because their numbers just don't work out for week 5 (the PK13/14 week). eg. it says the EC when added PK13/14 should be 2.2 but it was actually 2.6!! which I then diluted down with water to 2.0-2.1EC, so everything was diluted. Next feed I added the PK13/14 and then 10ml A and B at a time until EC was at about 2.1. Not ideal but their numbers were wrong so I had to improvise. Now that I am done with PK13/14 (only used for week 5) I hope not to have these problems from here on out, just concerned how badly i've damaged the plant.

JohnDee said:

GuitarGuy,
I tried to minmimize runoff by keeping my nutes really low. I was trying to avoid runoff because it's such a damn hassle. I'm now using trays, tilted just a bit, with drain hoses out the bottom. Still leaves a bit of water to mop up.

When I experienced this problem last winter...it occurred at around the same time. Latter part of flower. Demands go up ans it just takes awhile for the salts to accumulate.

Hey, if you flush...and I really feel you should, just be careful to not use straight water. 1/4 strength nutes or calmag so you don't wash out the calmag buffering of your coco.
JD

Click to expand...

Yes run-off and flushing is very uh, challenging and/or diffilut for me the way I have it set up this grow. I have a solution for the next grow but for the moment it's a PITA and I have not been feeding them to much runoff.

I've spoken to CANNA directly in the past about flushing and they recommend you don't flush at all unless you absolutely have to. They also said to flush it with full strength nutes what you would be feeding them anyways, so that's what i'm going to do. I would never flush plants midgrow with plain water, come on!
I have tapwater which presumably has some calcium and magnesium in it already, I can add CalMag and just reduce the amount of A and B so the EC doesn't get too high.

Thank you all for your help, I will let you know how things turn out. Cross my fingers.

EC of runoff is off the meter (> 3.6) and its pH is .... 3.8!!!

I ALWAYS pH my nutes, always 5.8-6.0 after a few days of offgasing (tapwater).

guitarguy10 said:

EC of runoff is off the meter (> 3.6) and its pH is .... 3.8!!!

I ALWAYS pH my nutes, always 5.8-6.0 after a few days of offgasing (tapwater).

Click to expand...

Half strength flush might do... till you have a lot a lot off run off... just my opinion! I have my own problems I’m no expert but it should help to get things back in order

Fed them pH 5.8, 1.8EC A/B/Zym/Boost/Rhizo/CalMag to about 20L runoff (each plant drinks about 3-4L every feeding, I have 4 plants).

The pH of runoff has come up closer to acceptable (from 3.8 to 5.0), I will make sure it goes up a bit more on next feeding. I will also be giving them EC 1.6 next feeding (and thereafter), just want to go down in steps gradual 2.2 to 1.8 to 1.6 vs. straight from 2.2 to 1.6. If I remember correctly EC of runoff has always been crazy high which is why I don't check runoff from my canna buffered coco, it's always been off the meter or close to that.

That was exhausting, I need a better method next grow, hope this does it cuz dunno if I have it in me to do more of this right now.

guitarguy10 said:

Fed them pH 5.8, 1.8EC A/B/Zym/Boost/Rhizo/CalMag to about 20L runoff (each plant drinks about 3-4L every feeding, I have 4 plants).

The pH of runoff has come up closer to acceptable (from 3.8 to 5.0), I will make sure it goes up a bit more on next feeding. I will also be giving them EC 1.6 next feeding (and thereafter), just want to go down in steps gradual 2.2 to 1.8 to 1.6 vs. straight from 2.2 to 1.6. If I remember correctly EC of runoff has always been crazy high which is why I don't check runoff from my canna buffered coco, it's always been off the meter or close to that.

That was exhausting, I need a better method next grow, hope this does it cuz dunno if I have it in me to do more of this right now.

Click to expand...

I have found that canna coco pro straight out of the bag (I use canna coco pro) is pre buffered to 1.5EC and does not require a buffer of Ca and Mg to stabilise it.

The only Ca and Mg my coco receives other than what’s in my base nutes is when I use additional nutes to add Ca or Mg.

Personally I never test runoff pH as coco pH runoff is always a bit whacky.

But the reason you’re seeing pH so low is because your salinity is so high.

Always with coco you must achieve 20% runoff whenever you water.

I also water before the coco dries out. By doing this you’re allowing the coco to never dry out fully which is where most salt build ups occur from if EC is under control.

Buffering coco imo is only required when using an inferior coco product or compressed coco bricks.