What’s going on here?

[Zebidee86]

Hey everyone, I’ve had some strange discolouration on my leaves - slight yellowing between the veins, which I had originally believed to be a mag deficiency so I had been treating the plant with Cal Mag with every feed but I’ve checked on it today and found that one of the fan leaves has a browning thing going on where it almost looks like it’s been scraped where the leaves are discoloured, not really sure what it is to be honest.

Indoor tent grow of barneys farm blueberry OG under 400w LED, 18/6 schedule 55-64% humidity (depending on when I’ve watered it) 22C temps, coco grow in 20L airpot, using biobizz bites and feeding every other day usually

The photo under lights was today, the other pic was from yesterday so this has happened overnight

 

[Chris Scorpio]

Why are the leaves wet?

Do u have a fan directly on it?

Never do pics under blurple, always natural light

 

[Zebidee86]

Why are the leaves wet?

I’d just watered it, they’re normally dry, I’ll get a natural light photo of it when I get home

 

[Zebidee86]

 

[Johnny5thesim]

I had a very similar thing. For me, I believe it was wind damage. I corrected fan placement and never had any more issues. So I’d give that some consideration. PH issues I think can also give you this kind of look!

 

[Bush Doctor 77]

Overall, it's a nice plant. You may have a little nute burn going on as I see some tips on other leaves burned, but unless it gets worse, or appears on new leaves, no sweat. Just try cutting back on nutes a bit.

 

[Johnny5thesim]

This is what I was seeing. My fix was moving fans. These pics show the progression for me.

It started by looking like yours. Then it slowly got worse. Until it would affect the entire leaf. And it didn’t stop with one leaf. It got worse until I moved fan.

 

[Barney86]

Overall, it's a nice plant. You may have a little nute burn going on as I see some tips on other leaves burned, but unless it gets worse, or appears on new leaves, no sweat. Just try cutting back on nutes a bit.

Yeah that'd be my advice too mate.
Always worth double checking the ph of the media too. Over strength nutes can easily throw it off.

 

[Metal Halide]

beautiful plant. Your new growth looks fine. I wouldn't worry about it. carry on

 

[Johnny5thesim]

beautiful plant. Your new growth looks fine. I wouldn't worry about it. carry on

If it’s what I had. New growth won’t be affected at all. It will just slowly affect leaf by leaf. For me it was my older lower leaves lower on the plant that were affected. And one by one it got worse and worse until I corrected the issue.

I first thought it was a PH issue with mobile elements because it was only on lower leaves. So I did some flushing to reset the medium. And it was slowly working it’s way up the plant. It made it to the third node before I got it under control.

Original poster, it would be great if you get this figured to let us know. I’d love to know how you remedied it.

 

[Zebidee86]

Thanks for all the advice, I had recently started using pH down as I’d noticed that I’d been feeding it water at about 7.2, the feed was only 6.4 ish the last few times, could it be shock from the pH change? Maybe flushing would fix it. I’ve only been giving it veg nutes as it’s been on 18/12 but I’ve seen a few pistils so maybe it’s starved of Potassium?

 

[Metal Halide]

Thanks for all the advice, I had recently started using pH down as I’d noticed that I’d been feeding it water at about 7.2, the feed was only 6.4 ish the last few times, could it be shock from the pH change? Maybe flushing would fix it. I’ve only been giving it veg nutes as it’s been on 18/12 but I’ve seen a few pistils so maybe it’s starved of Potassium?

yeah mate, keep at the veg nutes so long as you possibly top up with some cal/mag. If your PH was that off then yes id say that could most likely be it but you never know. Since its coco, give it a good %20 runoff with nutes and cal/mag. Never flush coco with water, always feed but less EC that you would hand feeding in soil unless in late veg/transition with heavy feeders. Unless its a serious problem or your doing final flush/totally changing nute regime, dont flush with water.

 

[Zebidee86]

So the problem just seems to be localised to a couple of early fan leaves and doesn’t seem to be spreading. I’ve noticed that whilst I’m watering with 6.2-6.5pH water, the run off is at 8.2pH, what does that mean? Should I be watering with much lower pH water?

 

[Barney86]

So the problem just seems to be localised to a couple of early fan leaves and doesn’t seem to be spreading. I’ve noticed that whilst I’m watering with 6.2-6.5pH water, the run off is at 8.2pH, what does that mean? Should I be watering with much lower pH water?

If it's going in at 6 and comming out at 8 then the ph of the media is most likely around 10 mate.
Think of it like running water through a teabag. It'll come out tasting like tea but you know fine well the contents of the teabag are much stronger.
You'll probably get some idiot popping up saying to ignore it cause run off ph is innacurate but don't. It's just soil growers that don't know any better.
Ph should be going in at 5.7 for veg. 6.2-6.5 for bloom.
You always have to water to run off every day as well or the nutes will build up and boil the media which causes the ph to rocket off in whatever direction.
Post a full plant pic so I can see the size and I'll be able to tell you what ppm to make the feed for the sweet spot.

 

[Purpsmagurps]

it needs to be 5.8 - 6.2 your in coco and feed every watering, just lower ppms no fresh water ever

 

[Zebidee86]

[QUOTE="Barney86, post: 4504082, member: 330316
Post a full plant pic so I can see the size and I'll be able to tell you what ppm to make the feed for the sweet spot

There’s probably about 6” of growth below the surface of the pot too, I didn’t have enough coco to fill the whole pot even though I used about 6 bricks!