Bright orange spots

Does anyone have an idea what might be the cause and fix for leaves getting bright orange spots on them. Growing granddaddy purple from seed. The plants will be 2 months old on the 10th. They seem to be growing good, they put on an inch of height overnight when I checked them this morning. Using Fox Farm Ocean Forest and Royal Gold Tupur 70/30 mix. They were up potted from 1 gallon to 7 gallon about 3 weeks ago. Watering with RO water ph 6.5 only additive 6ml Fish Sh!t to gallon RO. Started giving Cal Mag Xtra once a week’s a couple weeks ago. Temp is between 75-77 humidity 48-55. Lighting with lm301b qb leds. Have 8” exhaust and 8”intake fans plus 16” hurricane oscillating fan and 1 boxfan inside tent. Orange spots are at random spots on the plants. Some on bottom leaves some middle some close to top. Was told if it was a form of fungus mold it would rub off on fingers if you rub it, it does not transfer to fingers. I also am growing autos right next to the GDP and none of them are doing this.

A deficiency would be showing on lots of leaves so it looks more like you may have slopped some of that fish shit water on a few leaves.

Another thing it looks like is leaf sweat damage. That's when one leaf is draped over another and the moisture coming out of the upper leaf gets trapped between the two. The lower leaf then goes brown like that where the water is.

I'd trim out any damaged parts to make new damage easier to notice then keep an eye out for more before trying to add stuff to fix what may not be an issue.

They look great other than those few blemishes!

Yeah I agree with MedUser...I would think that a calcium def would be showing more so on the upper leaves and the areas on the plant that are growing the fastest.

It's magnesium. Beyond that, the damage isn't from bugs, but I see white specs on a lot of leaves. Just a heads up in case you want to check that.

3rd Monkey said:

It's magnesium. Beyond that, the damage isn't from bugs, but I see white specs on a lot of leaves. Just a heads up in case you want to check that.

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How do you figure Mg? Leaves fade to yellow between the veins long before spots develop with low Mg. Had that enough times to spot it right away. It's really bad when spots start with Mg. A little epsom salts fixes that up PDQ.

OldMedUser said:

How do you figure Mg? Leaves fade to yellow between the veins long before spots develop with low Mg. Had that enough times to spot it right away. It's really bad when spots start with Mg. A little epsom salts fixes that up PDQ.

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The VPD under QBs in a tupur blend feeding fish manure in RO water is how I figure.

Fish fertilizer is a very good fertilizer... in a maintained microbial soil. In a soil/coco blend, the CEC will accept the more readily available, easily bonding nutrients... NPK and even Ca in fish, which will "wash out" Mg.

Now, seeing as the only Mg provided was in that little bit of calmag once a week (RO water), its 2 months old and trying to push heavy photosynthesis under QBs with too low of humidity in temps that are a little too cool for QBs... Makes sense to me.

They don't always fade interveinally, but if you look at that spotting, it's edges and interveinal on the older fans and there's some leaf waffling.

QBs are a different animal and they burn through Mg and K very fast, K being easier to cling in coco and in soil... leaving Mg out... especially with transpiration rates under QBs.

3rd Monkey said:

The VPD under QBs in a tupur blend feeding fish manure in RO water is how I figure.

Fish fertilizer is a very good fertilizer... in a maintained microbial soil. In a soil/coco blend, the CEC will accept the more readily available, easily bonding nutrients... NPK and even Ca in fish, which will "wash out" Mg.

Now, seeing as the only Mg provided was in that little bit of calmag once a week (RO water), its 2 months old and trying to push heavy photosynthesis under QBs with too low of humidity in temps that are a little too cool for QBs... Makes sense to me.

They don't always fade interveinally, but if you look at that spotting, it's edges and interveinal on the older fans and there's some leaf waffling.

QBs are a different animal and they burn through Mg and K very fast, K being easier to cling in coco and in soil... leaving Mg out... especially with transpiration rates under QBs.

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From what I understand Fish Sh!t is not the same as fish fertilizer it is a soil conditioner. Was told it contains no nutrients at all only provides beneficial bacteria and microorganisms. If it is a Mag def should I increase Cal Mag Xtra to twice a week instead of once

3rd Monkey said:

The VPD under QBs in a tupur blend feeding fish manure in RO water is how I figure.

Fish fertilizer is a very good fertilizer... in a maintained microbial soil. In a soil/coco blend, the CEC will accept the more readily available, easily bonding nutrients... NPK and even Ca in fish, which will "wash out" Mg.

Now, seeing as the only Mg provided was in that little bit of calmag once a week (RO water), its 2 months old and trying to push heavy photosynthesis under QBs with too low of humidity in temps that are a little too cool for QBs... Makes sense to me.

They don't always fade interveinally, but if you look at that spotting, it's edges and interveinal on the older fans and there's some leaf waffling.

QBs are a different animal and they burn through Mg and K very fast, K being easier to cling in coco and in soil... leaving Mg out... especially with transpiration rates under QBs.

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I'll have to take your word for it as I don't do coco or QBs.

Low Mg would be affecting the bulk of the older fan leaves no matter the growing conditions and not just a few scattered ones.

I still vote for water damage.

spirtwolf said:

From what I understand Fish Sh!t is not the same as fish fertilizer it is a soil conditioner. Was told it contains no nutrients at all only provides beneficial bacteria and microorganisms. If it is a Mag def should I increase Cal Mag Xtra to twice a week instead of once

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Ah, ok my bad. I thought you were talking about fish shit, not a product lol.

Epsom salts work fine. Foliar or in your water. It's hard to overdo calcium, but it can be done.

OldMedUser said:

I'll have to take your word for it as I don't do coco or QBs.

Low Mg would be affecting the bulk of the older fan leaves no matter the growing conditions and not just a few scattered ones.

I still vote for water damage.

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In soil, I would agree with you.

As far as water damage... I don't think so at all, but OP can wait it out a bit. Pretty sure more leaves will start showing symptoms fairly quickly though.

My 2c.
He transplanted from 1 gallon to 7 gallon pots of ffof 3 weeks ago.
My guess would be the leaf damage was more related to when it was in a 1 gallon pot.
I can't imagine 7 gallons of ffof needing anything but water and maybe small amounts of cal/mag for a long time before deficiencies develop.
Looking at the leaves makes me feel the plants have not been watered properly and any nutes other than cal/mag may have done more harm than good.