What is happening to my leaves?

I have 4 plants from fastbuds in total:
1 Green Crack Auto
1 Lemon Pie Auto
2 Gorilla Cookies Auto

In the beginning about 3 weeks into flower, a few of the top larger fan leaves on the lemon pie cola closest to the light started to get some rusty spots. After researching, I thought it was rust fungus at first. But when rubbing on the leaves, nothing rubbed off on my fingers. Then I was thinking that it was a lack of calmag, calcium in particular. But I was already supplementing 1.5mg of calmag+ per liter. Then I was thinking that maybe my ph of 5.8-6.0 was too low and was not getting enough calcium.

By this time, a few more leaves started to get it, along with the 2 other Gorilla Cookies near the top of the colas closest to the center where the light is more intense, but absolutely nothing on the Green Crack. I was thinking if this was indeed some sort of fungus, then why would it hit 3 of the plants, but absolutely nothing on the 3rd (the green crack), which is butted right up against the other plants? I eventually raised my ph to 6.3 and 6.4 thinking that it was a calcium issue, and even giving 2mg per liter of calmag+. But this still hasn't changed a thing. Even some of the sugar leaves have some mild spotting on them. It has eventually spread to more fan leaves on the plants (except the green crack), but only towards the top. I'm now on day 100, and bud development still looks a little slower than normal at this stage. Can anyone tell me what this is and what I'm doing wrong? The Green Crack is looks perfect, but it usually doesn't need as much nutes as the other 2 strains.

Stats:
-600w LED, about 15 inches/40cm above the canopy
-Coco with 30% perlite
-20 degrees C temp normally, 70% humidity

Nutes:
3mg/liter Biobizz BioBloom
4mg/liter Green Buzz Liquids bloom, 4mg/liter Big Fruits
1.5mg/liter Calmag+

Feeding every 3rd day (when it starts to look dry)

Pic of whole plant would help a lot more then the spots.

Looks like its lacking K but i could be wrong. thats a guess.

600 watts of good leds is a LOT of light. 15" is very close. Thats your issue, you need to compensate the extra light with more of other things....or back off the light some.

getogrow said:

Pic of whole plant would help a lot more then the spots.

Looks like its lacking K but i could be wrong. thats a guess.

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Ok, I only took pics on the leaves on top that were affected. The middle and lower leaves look great and have no marks at all. Just the ones near the top of the colas.

NugDragon said:

Ok, I only took pics on the leaves on top that were affected. The middle and lower leaves look great and have no marks at all. Just the ones near the top of the colas.

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That tells me that it is the light being too intense for your environment.
You can add food and co2 to make up for the extra light but in my world thats hard to do , so i would just raise the light at least 10".

Calcium is out of balance.

Looks like a Calcium deficiency to me

Probably more than 15 inches, actually. I've grown in this tent for a good 6 or 7 runs and never had an issue with light burn yet.

Herb & Suds said:

Looks like a Calcium deficiency to me

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Why isn't basically doubling the amount of recommended calcium and boosting the PH higher to 6.3-6.4 working at all then?

NugDragon said:

Why isn't basically doubling the amount of recommended calcium and boosting the PH higher to 6.3-6.4 working at all then?

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It may be but
You aren't going to reverse the damage
Just grow thru it

NugDragon said:

-Coco with 30% perlite

Feeding every 3rd day (when it starts to look dry)

Click to expand...

You're treating coco like soil.

Herb & Suds said:

It may be but
You aren't going to reverse the damage
Just grow thru it

Click to expand...

I'm wondering why it is getting worse and spreading to other leaves now, though. I figured giving 2mg of calmag per liter was pleeenty enough to correct a deficiency, as well as significantly raising my PH.

xtsho said:

You're treating coco like soil.

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In what way? If I water more often, I'll get (and have had) fungus gnats. Had some problems watering too often.

xtsho said:

You're treating coco like soil.

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I would sure like to know the fix then.

He obviously is not low on Ca or mag. his ph may be out of wack but the food is there.

I dont get it but he is saying to water it almost everyday to fix it. im not a coco guy so i just have to agree.....

If the coco gods are real then you would feed them the same amount you are now but spread one feeding into 3. Weak feed 3 days in a row vs one big feed every 3 days.
Supposedly , thats the fix for coco.
I dont like the info but it may be accurate ....if im wrong im wrong.

NugDragon said:

Why isn't basically doubling the amount of recommended calcium and boosting the PH higher to 6.3-6.4 working at all then?

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May be that the leaves will never recover, or it could be nutrient lockout of calcium. Or an antagonist effect. I think its potassium that will negatively affect calcium if used in excess. I forget but its called Mulders Chart.

NugDragon said:

In what way? If I water more often, I'll get (and have had) fungus gnats. Had some problems watering too often.

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What size pots are you using? With coco you don't want to let it dry out. Plants that size can be watered daily and the coco shouldn't stay too wet. But environmental factors play a part.

"-20 degrees C temp normally, 70% humidity"

You're temps are a little low and your humidity is pretty high for plants that far along in flower. That will slow the coco from drying not to mention the potential for mold. They also look a little overfed. Why are you using 2 different bloom nutrients? I don't know what's in those nutrients you're using but too much of anything can cause nutrient antagonism making other nutrients unavailable to the plant. Too much potassium and phosphorus can lock out calcium and other things. That's why I asked about using two bloom nutrients as most are high in P&K. Have you grown this way before without issue? Or has something changed this grow?

getogrow said:

I would sure like to know the fix then.

He obviously is not low on Ca or mag. his ph may be out of wack but the food is there.

I dont get it but he is saying to water it almost everyday to fix it. im not a coco guy so i just have to agree.....

Click to expand...

Actually I'm one of the few coco growers that doesn't believe you need to water everyday if the coco is really wet. Most say to water daily despite plant size or how wet the coco is. But there's a balance. You don't want it to dry out like with soil though.

Looks like a combination of factors at play. You mentioned the light was too close. I don't grow with LED's but it looks like the worst leaves are right in the middle where they would receive the most intense light. That might be playing a part.

ebcrew said:

May be that the leaves will never recover, or it could be nutrient lockout of calcium. Or an antagonist effect. I think its potassium that will negatively affect calcium if used in excess. I forget but its called Mulders Chart.

Click to expand...

Both potassium and phosphorus can affect calcium uptake.

getogrow said:

If the coco gods are real then you would feed them the same amount you are now but spread one feeding into 3. Weak feed 3 days in a row vs one big feed every 3 days.
Supposedly , thats the fix for coco.
I dont like the info but it may be accurate ....if im wrong im wrong.

Click to expand...

I will run into fungus gnat issues if my coco is always this wet. I've had bad issues with this in the past in the same setup here. The plants have reacted far greater after less often waterings. I don't wait until its entirely dry, but I have my waterings dialed in pretty good by now, and have never seen this happen before. My ph in veg is at 5.8, and then slowly raise it to 6.0 after it starts to flower for a bit. But since that wasn't fixing the issue, I boosted my PH and calmag so calcium is better absorbed and there is more available. But that still didn't take care of the issue, because I still don't know what it is.

xtsho said:

What size pots are you using? With coco you don't want to let it dry out. Plants that size can be watered daily and the coco shouldn't stay too wet. But environmental factors play a part.

"-20 degrees C temp normally, 70% humidity"

You're temps are a little low and your humidity is pretty high for plants that far along in flower. That will slow the coco from drying not to mention the potential for mold. They also look a little overfed. Why are you using 2 different bloom nutrients? I don't know what's in those nutrients you're using but too much of anything can cause nutrient antagonism making other nutrients unavailable to the plant. Too much potassium and phosphorus can lock out calcium and other things. That's why I asked about using two bloom nutrients as most are high in P&K. Have you grown this way before without issue? Or has something changed this grow?




Actually I'm one of the few coco growers that doesn't believe you need to water everyday if the coco is really wet. Most say to water daily despite plant size or how wet the coco is. But there's a balance. You don't want it to dry out like with soil though.

Looks like a combination of factors at play. You mentioned the light was too close. I don't grow with LED's but it looks like the worst leaves are right in the middle where they would receive the most intense light. That might be playing a part.

Click to expand...

8liter fabric pots. The humidity is indeed high, but we have had some very humid weather these last few weeks. I usually have my waterings dialed in by now, I have a good feel with the weight, the color and texture of the coco, and how the leaves are standing for when its time to water. It's not an exact schedule, but I don't think that's an issue.

I have been using both biobizz and green buzz liquids because I have read great things about green buzz liquids and wanted to try their line and I'm almost finished with the rest of the biobizz. Both bloom nutes have different npk ratios, and I figured that using a relative modest amount of both would give the plants a wide array of varied organic ingredients/sources. Maybe mixing the two bloom nutes together is creating an issue, but I didn't really think at these doses would really hurt a lot.

Do you think I should lay off the bloom nutes by half, and maybe then calcium won't be as locked out? I think the chances of some sort of lockout seem higher than an actual deficiency. Because running 2mg/liter of calmag is super high.