Nute burn? Light stress? CalMag problems?

Hey peeps. Trying to figure out what's going on with one of my 3 girls. All 3 Shiskaberrys. All 3 in 5 gallon fabric pots using Fox Farms Ocean Forest soil. About 5 weeks into flower. Using mars hydro ts2000 at about 16" above canopy. Used ff trio nutes sparingly throughout their life cycle. Anyone got input on what this probably is? Or maybe a combination of problems? It's only happening to the one, the other two don't even have yellow tips on their leaves. This one was by far always closest to the light. It reached for it way faster than the other 2. I go very easy on the nutes, maybe half strength and only once a week not twice. It may be a little difficult to see in the pictures but some of the affected leaves have the brown running all along the serrated edges as well. Also, in one picture, you can see how the half of the node site is affected (the half closest to the light) while the other half seems fine. This all happened with 4-6 days. Figured I'd get some advice from you folks. All 3 get the same amount of nutes as well. Any help would be greatly appreciated. Everything has been going great up until this happened. I haven't used nutes in probably 2 weeks. Also, ask any questions you might have. Cheers

My guess would be potassium deficiency locked out from excess nitrogen. I'd start by lowering it's nitrogen intake by a lot and see if it stops on other leaves.

Do you use calmag? Often plants will try to rid extra nitrogen on ends of leaves causing the tip burn.
Hard to tell in the pic of the shade of green.
You haven't fed much so hard to tell,if it was the light then we'd see some yellow.What are leaf temps closest to the light?
Potassium deficiency is likely ,not much food 5 week flower.

myke said:

Do you use calmag? Often plants will try to rid extra nitrogen on ends of leaves causing the tip burn.
Hard to tell in the pic of the shade of green.
You haven't fed much so hard to tell,if it was the light then we'd see some yellow.What are leaf temps closest to the light?
Potassium deficiency is likely ,not much food 5 week flower.

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Plant looks super green in the pictures, despite saying be hasn't fed it much. Possibly that the soil is nutrient rich and he's been feeding on top of that?

That's not nutrient burn though.

twentyeight.threefive said:

Plant looks super green in the pictures, despite saying be hasn't fed it much. Possibly that the soil is nutrient rich and he's been feeding on top of that?

That's not nutrient burn though.

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Yeah it's overall pretty dark green. Couple weeks ago there was some slight clawing. Knew it was having an N problem. So, that's when I began really easing up on the nutes. I know the Grow Big in ff trio is very hot with Nitrogen. Maybe it built up heavily in the soil when I was hitting them with the nutes? The temperature on the leaves is not very hot at all. They are LED's though. Haven't used CalMag.

Well you still have 4-5 weeks so should be enough time to use it up.

myke said:

Well you still have 4-5 weeks so should be enough time to use it up.

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Think I should flush it? Increase/decrease watering? Give a little bit of nutes, possibly just the Big Bloom? Very very little N in that one and a bunch of good stuff. A pretty gentle nute as far as I've read. Never had this problem before. If it's a lockout.. well that's a whole new problem I've never had to deal with lol.

Coopalooop said:

Think I should flush it? Increase/decrease watering? Give a little bit of nutes, possibly just the Big Bloom? Very very little N in that one and a bunch of good stuff. A pretty gentle nute as far as I've read. Never had this problem before. If it's a lockout.. well that's a whole new problem I've never had to deal with lol.

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When you feed FF trio what ppm/EC are you feeding at?

As I said earlier I'd cut down on the nitrogen, not completely but significantly.

I'd just give straight water with no runoff for now.
Even in straight promix when i'd notice salt buildup, i could water for 2 weeks straight water, with 0 fading.
I honestly wouldnt be surprised if you had enough nutrients built up to carry you to harvest; if you dont allow runoff thatt is.

Most all my experience is hydro,Ive helped other people with their dirt plants,feed to runoff all the time.Flushes out the old and new takes its place.Just like hydro.20-30% runoff,plants love it.