Cant figure it out (dry tips, sides, spots on leaves)

endorflight

endorflight

New Member
I cannot figure out whats wrong.

The strain is Permanent Marker, 4 weeks into flowering. I currently give 50% strength AN nutes in a HPA system. I messed a lot with the spray times, but it seems that iam somewhere in the right zone now.

I had tried less and more nutrients, with and without cal mag, always to some degree with signs on the leaves that look to me most like potassium deficiency.

EC is currently 1.5. Before that i went as low as 0.6.
 

Attachments

C

cage

Well-Known Member
It does look like some potassium deficiency..

How's your source water? And how much you've been using cal-mag?
Too much cal-mag might reduce your potassium intake even if there is enough potassium in the feed.
 
endorflight

endorflight

New Member
The lights are two HortiOne 600 dimmed to 800 PPFD. Due to stretch and limited ability to move the lights higher (i fixed it now) the plants might have received 1000-1200 PPFD for a few days. And the temps are also relatively high at 25-28 C.

The sides of the leaves are not turning up but the tips are curling down.

My water source is RO water with 0.04 EC. I tried to go without cal mag as it seems to be not necessary with AN, however the informations i collected are still unclear. Iam using AN conisseur line, basically with all products.

I increased from 25% to 50% nutrient strength, then got more clear calcium deficiency and added cal mag, after that the burn or potassium deficiency seems to increase/return. The cal mag i added was about 0.2-0.3 EC.
 
C

cage

Well-Known Member
endorflight said:
The lights are two HortiOne 600 dimmed to 800 PPFD. Due to stretch and limited ability to move the lights higher (i fixed it now) the plants might have received 1000-1200 PPFD for a few days. And the temps are also relatively high at 25-28 C.

The sides of the leaves are not turning up but the tips are curling down.

My water source is RO water with 0.04 EC. I tried to go without cal mag as it seems to be not necessary with AN, however the informations i collected are still unclear. Iam using AN conisseur line, basically with all products.

I increased from 25% to 50% nutrient strength, then got more clear calcium deficiency and added cal mag, after that the burn or potassium deficiency seems to increase/return. The cal mag i added was about 0.2-0.3 EC.
Click to expand...
1:1 ratio of the part A and B seems to have pretty good balance on the K-Cal-Mag.
Around 4 : 1 : 0,3 ratio for K:Ca:Mg.

With this I wouldn't add any extra Cal-Mag.

Temps and PPFD's has been on the upper end, but should be manageble
 
endorflight

endorflight

New Member
I reduced the nutrient strength again to 25% without the cal mag.

PH is at 5.8 and EC at 0.84.

I just dont understand the dynamics of nutrient uptake in high pressure aeroponics. I currently spray 3 seconds, with 180 seconds pause. If i spray so little wouldnt i have to increase the nutrient strength instead of running it so low? I dont get it, i even wonder that the plants survive at all with so little water.

Could also be that my problem comes from overwatering/underwatering.

As far as i can calculate it, i feed 4.7 L / 1.2 gal per plant per day.
 
D

DudeTheDevin

New Member
What is your RH? 25-28c temps should be perfect unless RH is below 50%.

Other thing you might try is to raise your PH to 6.0-6.1 so it can absorb different nutes better.
 
C

cage

Well-Known Member
endorflight said:
I reduced the nutrient strength again to 25% without the cal mag.

PH is at 5.8 and EC at 0.84.

I just dont understand the dynamics of nutrient uptake in high pressure aeroponics. I currently spray 3 seconds, with 180 seconds pause. If i spray so little wouldnt i have to increase the nutrient strength instead of running it so low? I dont get it, i even wonder that the plants survive at all with so little water.

Could also be that my problem comes from overwatering/underwatering.

As far as i can calculate it, i feed 4.7 L / 1.2 gal per plant per day.
Click to expand...
Hopefully someone with experience on pressure aeroponics could chime in.
I'm not really familiar with it.

But as you calculated 4.7L of water per plant should be plenty enough.
With 180s feed interval it shouldn't dry up too bad either.

Roots still looking good?
 
endorflight

endorflight

New Member
The roots took some damange earlier in the grow but mostly recovered.

As the symptoms didnt went away but also didnt increase much over the weekend. Suspecting potassium deficiency, i gave a bit more PK booster. It seems that the symptoms have increased a bit, so i looked at "Potassium excess".

A symptom of potassium excess seems to be an acidic runoff PH. I measured the runoff and it was 4.9 while the reservoir is at 6.0.

What also drives me crazy is, the tips are curled down. More a sign of burn than deficiency right?

Could it be that i just burned them with PK?

On the other hand i keep reading in some old HPA/TAG threads that HPA plants require much more potassium?

Here are some newer pictures with grow lights off.
 

Attachments

C

cage

Well-Known Member
endorflight said:
The roots took some damange earlier in the grow but mostly recovered.

As the symptoms didnt went away but also didnt increase much over the weekend. Suspecting potassium deficiency, i gave a bit more PK booster. It seems that the symptoms have increased a bit, so i looked at "Potassium excess".

A symptom of potassium excess seems to be an acidic runoff PH. I measured the runoff and it was 4.9 while the reservoir is at 6.0.

What also drives me crazy is, the tips are curled down. More a sign of burn than deficiency right?

Could it be that i just burned them with PK?

On the other hand i keep reading in some old HPA/TAG threads that HPA plants require much more potassium?

Here are some newer pictures with grow lights off.
Click to expand...
Ye, damaged parts don't really get fixed. Slightly underfed parts will recover fully.
So it seems you might have been on the right track with the increased K?
I still don't think it would be an excess.
With excess you see the leaf tip progressively getting burnt further, not so much on the leaf margins.

As for tips starting to claw and overall look getting pretty green,
you might be leaning into over N now, so fully switch into later flower feeding and limit the N.

The runoff pH is something to consider, could you also measure the EC from it?
And it doesn't get re-circulated?

1725371511149.png

This bleaching getting inwards, could also be start of magnesium deficiency. Keep an eye on it and consider adding a bit of magnesium.
 
Last edited:
endorflight

endorflight

New Member
I already apply mid/late flower nutrients. The only thing that would change later, according to the AN schema, is the addition of "Overdrive".

Iam still totally clueless, however with my little information iam still leaning towards excess. The problem seems to be still "active". Newer leaves seem to get affected.

The system is recirculating but i detatched the drain to be able to finally take some runoff readings.

I measured them again right now.

PH
6.0 in
4.75 out

EC
0.920 in
0.980 out

These measurings should be very precise as the sensors are freshly calibrated and i have reducancy 2xPH, 2xEC.
 
endorflight

endorflight

New Member
I found this somewhere:

"When runoff pH is lower than input pH - Usually, if the pH is lower by more than .5 points of the input pH then you are overfeeding."

"When runoff pH is higher than input pH- Usually if the pH is higher than .5 point of the input pH then you are not feeding enough and the plant can use a higher feed EC."

That would be an indication for overfeeding. Somewhere else i read underwatering can also be a cause.

I notice i have very little runoff.

Maybe a bit more watering and bit less nutrient strength?
 
C

cage

Well-Known Member
endorflight said:
I found this somewhere:

"When runoff pH is lower than input pH - Usually, if the pH is lower by more than .5 points of the input pH then you are overfeeding."

"When runoff pH is higher than input pH- Usually if the pH is higher than .5 point of the input pH then you are not feeding enough and the plant can use a higher feed EC."

That would be an indication for overfeeding. Somewhere else i read underwatering can also be a cause.

I notice i have very little runoff.

Maybe a bit more watering and bit less nutrient strength?
Click to expand...
If your EC rises, this means the nutes are accumulating. Electrical Conductivity doesn't differentiate between nutes.
Even stable EC can eventually run out of some nutrient, but be abundant in others.
Though it probably won't stay stable after that.
Water change interval?

The pH drop seems bit high. Some would be expected if the EC rises, but might there be something unwanted brewing there?
 
You must log in or register to reply here.
Top