Sick girl

[perp]

Hello all, Have been growing for some time now (about 2 years) and am about to start a perpetual grow from clones. I have three ladies grown from seed at various stages of flower. 1 is about a week away from harvest one a week behind that and my problem girl about 2 weeks behind that.

I noticed copper coloured blotches on the leaves about a week ago, since then the leaves have curled up at the tips and have gone dry and crispy. Seems to be mainly on the young leaves, although it is spreading to the fan leaves too.

Please see attached pics.

I am growing in "Plagron Grow Mix" in 10 litre tubs, flowering under 600 W HPS.
Feeding Alga Bloom at every feed. Ph of feed water 6-6.5. Room temps of between 65deg lights off and 80deg lights on.

Other 2 ladies a few weeks closer to harvest are fine and looking healthy.

Have flushed medium through a couple of days ago, and am just giving ph'd water at the moment.

Any ideas what this could be?

 

[greenisgold]

What's a bummer is that there is no way that plant will get better this far into flower. Usually rust/copper spots are related to ph problems, but that plant looks seriously sick. Tips curling like that is due to too much nutes.

 

[Classyathome]

Sounds like N toxicity - any chance the affected ladies were served too strong a nute?

 

[geopolitical]

I'd have to agree, that sure looks like nute burn to me. The damage that's visible isn't going to get any better looking, it's dead tissue, but if you've remedied the plants may rebound and start packing on bud again. Some will, some won't.

 

[GreenDream]

Burn baby burn!

You ever check your runoff pH and EC? It's probably too late now that you've been flushing, but for future reference, keep track of what's going in and what's coming out!

 

[perp]

Thanks for the input guys, I have recently checked runoff ph on one of the healthy girls, and its coming through at about 5.7. Water going in is at between 6-6.5. Unfortunately i cant check EC. Other 2 girls are very green, even at this late stage of flowering.

Will try upping ph of feed water on all 3 and cut nutes for a few days.
Have attached a shot of one of the healthy girls