Lots of leaf issues in coco - maybe tent offgassing?

[ScrubNinja]

I have a Growlush propagation tent. It's my first grow in it and I'm on day 39 of 12/12. For a couple of weeks now I've had this continual die back of lower leaves. Sometimes I thought I'd fixed it but it would keep returning.



They start dying at the tips and going brown or speckly brown and spread up the leaf and then it's just dead. The underside has a real pale/whitish look to it that didn't come up on camera. It's slow, but unrelenting. It's affected all 3 plants. (1 x The Pure, 2 x Shiva Skunk)

Now since yesterday I've noticed weird yellow blotching and burning on the top side of my scrog screen. Only one of the Shivas seems to be affected for now. Here are examples:



And tonight I looked at one of my favourite buds on that same plant and I thought it was attacked by insects or something! It's way at the back so I had to hold my camera in there and rely on that. What looked like insects is just more yellow blotches and these particular ones close up really remind me of variagation you see on some houseplants. It's freaking me out cos it's right at the bud and all over it! (just this one bud for now) Here's a close-up and a not-so-close-up.



I've been feeding really lightly for ages, like 1.0 to 1.2 ec max, and they've always looked over nuted to me. I've been watering with ph'd water for 3 or 4 days trying to get a grip on this but things are going downhill fast. I had raised the ph for a week or two to 6.1ish just before the original lower leaf dieback started, and figured I'd induced some kind of lockout or whatever cos I never go that high and that's the only thing I've done differently technique-wise from succesful grows, apart from me using a city water supply this time.

And then I came here to make this thread and saw the tent offgassing sticky and the symptoms really seem to describe it, but the photos on that thread seem distinctly different from mine?

I'm at a loss here guys Please help

 

[shaunmulok]

Hey ScrubNinja, sorry i cant help but it looks nasty, i was about to purchase one of these from an online suplier that i have used a few times i might hold off and see what you figure out

 

[ScrubNinja]

Will do shaun. Got the pm as well. Thanks for reading.

Has anyone experienced gassing this late in the grow? They've been great until these problems appeared several weeks into flower.

 

[Max0r]

ScrubNinja:

Sorry about your troubles man.
I don't have any experience with coco but might a flush be in order?
You said you were messing with the pH as an experiment and you're pretty far along at this point so you may be dealing with a major buildup. Not sure but I doubt it could hurt much to flush at this point? I'm sure someone else with more experience will chime in.

Maybe add some more details about your medium and nutes to help flesh it out.

 

[BobbleheadJed]

My guess is that you are having some root issues that you may be able to fix. I have no experience with tents yet, so I can't answer you there.

That looks like some of what I experienced the first time I ran coco. Are you checking the ph and EC of your run-off? That may give you an idea if it is nute lock out from either ph drift or salt build up or both. How big are the pots you are using and how often are you watering? What kind of nutes?

Something I might try would be to feed at half strength nutes every day(or more often if you already do) for the next three days with plenty of run off. And measure the run off levels if you want. If it comes out at 6.6 ph that would be useful to know. Try a lower ph of 5.6-5.8 to water them with. If I had followed some of that my first run I might have had a chance. You can use a much lower nute level in coco if you water it more often and the ph doesn't drift as far between waterings and they have a fresh plate more often. Some thoughts that have nothing to do with tents. Sorry. Good luck.

 

[D.I.trY]

scrub, extremely sorry to hear this - from the bottom of my heart! Don't worry yourself unecessarily. I know this user richyrich who created a long detailed thread about a possible salt buildup over time in coco, just recently - search by that username - and theres good input from others too. The thread is filled with information on a coco problem and its definately worth a read to find out more about whether the coco is beginning to lock out nutrients due to salt builup over time. The first time i ever grew was in coco, takes me back! I really dont know much about it now but I remember canna developing special nutes to combat coco specific nute lockouts. Keep us posted.

 

[ScrubNinja]

Thanks so much guys, appreciate it a LOT! I'm pretty frazzled after a long day's work and I just got home and rushed here, lol. There's too many things to address individually, so I'll try to answer them all in points.

• I've been flushing the last 4 days and it kept getting worse
• Using Dutch Master Gold nutes and they've served me well in past coco grows. Note: they are about 7 months old and I did have an issue a week or so ago when I found some of the part B had "crystalized" or collected on the bottom. The bottle is still pretty full and I shook the crap out of both bottles. I normally give them a little shake before every single mix. Also, Dutch Master mentions the crystals in their FAQ and say it's nothing to worry about. They haven't been kept in the sun or heat or anything like that.
• I normally watered this grow @ around 1.2 ec max and ph of 5.8
• I started checking the runoff when I started flushing and a few random points before that, and very sparsely in other good grows. On each flush, the ec dropped from around 1.6 down to 0.8 last night, the runoff ph has always been high, from 6.4 to 6.6... I have no idea but this seems generally consistent with the few times I checked runoff on succesful grows.
• I nuted them @ 1.0ec and 5.7ph last night, cos 4 days seemed like a stretch on pure water when they should be in peak budding mode
• Pots are 4.5 litres, pure coco (GH Cocotek brick, used em before no probs)
• Normally feed/water every second day, but switched to every day since starting the recent flushing 4 days ago
• I flushed approx once a week before any of this problem happened

I agree with your suggestion jed. I think that's what I would have done using my intuition. I'm remaining confident here! Let's get these girls finished up nicely!

I'll check out that thread now matey. You're all very helpful and, no shit, I have a warm lil feeling knowing IC is there. Mad props fellas!