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Urgent Advice Needed Please - All leaves turning yellow!


New Member
Hi peeps,

Been using the site to help me through my first grow, but first time posting.

I've been desperately trying to diagnose the problem , but so many opinions not sure which one it is..
I'll try and keep this brief,

3 weeks into flowering, 9 plants under 2 600w hps lights, growing in coco and using canna a+b, as well as a number of other additives calmag etc, (as I use RO water) all of them started to turn yellow from the bottom up pretty much when I switched to flower.

Assumed it was N def, so loaded up, no change, even worse actually. Then discovered I was infested with White fly, aphids, whatever the F they're called, those tiny White/yellow things on the underside of the leaves causing white spots everywhere . Got rid of those with insecticide, then I must of brought some white powder mould from my outdoor infected plants, into the indoor tent, and apparently a big nitrogen boost is exactly what WPM needs to flare up, hence the flare up ..

So I'm just getting rid of the mould at the moment, but in this time, I've nearly lost every main fan leaf from nearly all of the plants. Started at the bottom gradually moving all the way up the plant, leaves dropping like flies. Unfortunately the flies still living in the coco aren't dropping as quick as those flies.. Ok that's another thing I forgot I've got to kill the soil flies. Not sure what u call those lil f*cks.. So I've got these tall ass trees with no leaves but still lovely looking buds, they still seem to be growing ok, but every leaf is basically going yellow, they have green veins still as they die, but then go bright yellow and fall off, or I get upset looking at them for too long and rip them off myself with tears in my eyes... I flushed them all with ph'd RO water a few days ago, the indicas have dried out a bit since then, but the sativa pots are still heavy.. Which is worrying.. That may not be connected but I remember it being the other way around when they were healthy...?

Someone help me, I'm getting majorly stressed out, my beautiful girls, that I've devoted all my time to since seed, look like they're fucking dying!! And fast!!

Can someone tell me otherwise!!

I've tried all of the usual fixes, N, then no N, then plain water, then flush, temps and humidity are perfect so it's not that, bulbs are at good distance, and I don't over do it with water. Every 3-4 days, sometimes longer if needed .

WTF is going on!! Could it be the roots?? Do I have a pot full of bugs feeding on my roots and nutes..?? This is what I'm leaning towards.Haven't checked roots as yet. But going to, but don't really know what I'm looking for.. Bug wise I mean.

Please let me know if I've left any vital info out that may help to diagnose.

Thanks in advance,



Plant of the Year: 2014 - Plant of the Month: Dec 2014 - Nug of the Month: Feb 2015, Mar & Aug 2016, Dec 2017, Aug 2018, Jan 2019 - Nug of the Year: 2017 - Photo of the Month: June 2018
Re: URGENT ADVICE NEEDED PLZ!!!!! All leaves turning yellow!

I would suggest you try to get BigIrishDoode's attention on his journal. He's really familiar with coco.

Your issues are familiar, but you're in coco and I'm in high brix soil, so our environments aren't the same. The pests showed up because your plants are sick, I think, not the other way around. Now they're a problem, but mostly 'cause the plants weren't very healthy. I have a small population of whiteflies, but they're manageable because my plants are healthy.

The lack of fan leaves isn't a deal-breaker, provided they're getting close to finish. If you're 3-4 weeks away, you'll still get a decent harvest, or better.

:3: Breathe.


New Member
Re: URGENT ADVICE NEEDED PLZ!!!!! All leaves turning yellow!

Ok thanks I'll try to get hold if him . Im thinking about introducing nutrients again following the flush I did about 4 days ago , (when they dry out ) but I'm worried that this was the original problem , loving them too much and over doing the nutrients...

But they all look so pale, like they're desperate for some food! Starting to also wonder if my Ph pen is misreading.. It's a decent one and I've only had it about 3 or 4 months so should it need buffering with the fluid again already you think ? It's obviously not a N def, as when I loaded it up with N , it didn't do anything at all, so lack of nutes can't be the problem? What's the best thing to do next!?

Aside from taking a breath of course ;)

Maybe I'm locking out Magnesium with a dodgy ph pen reading ? When I use the photo diagnosis chart, it looks a lot like magnesium deficiency , but then again I use calmag with every feed.. Will I ever work this out., maybe not !!

Thanks for the advice so far


Plant of the Year: 2014 - Plant of the Month: Dec 2014 - Nug of the Month: Feb 2015, Mar & Aug 2016, Dec 2017, Aug 2018, Jan 2019 - Nug of the Year: 2017 - Photo of the Month: June 2018
I remember BID saying that coco really needed CalMag suppliment - didn't hold onto it worth a crap ...


Well-Known Member
PH pens should be calibrated every 30 days.

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