PICS! browning leaves with holes

Hey guys,

I've got a problem with one of my 12 day old seedlings, about 4 days ago I noticed a couple of small holes in one of the lower leaves then a part of the leaf started to go brown, the pics below are a couple of days old and the browning has progressed.

The other 2 girls are fine and they're all chronic haze feminised.

The set up:

2 x 125w cfl (1 blue, 1 red)
Biobizz lightmix
Started using Biobizz grow on about day six (2ml/l), maybe a bit early??
run off ph around 6-7

It's a bit of a chin stroker but any advice would be much appreciated! bTW the second and third pic are my other girls

the brown spot in unsure of. however the holes look like youve got a visitor in there helping them selves to a canna buffet.

cheeky barstewards. I've read something along the lines of spraying with water and a tiny bit of washing up liquid, what say you?! Thanks for the comment matey

look here for some help in identifing the problem and some info on solutions. hope this helps you out

https://www.rollitup.org/view.php?pg=faq&cmd=category&id=33

Thought I'd take the knackered leaf off for a closer look - can't see bugs anywhere, I've had them before and they seemed quite obvious - the link posted above mentioned N deficiency but I've been feeding Biobizz grow for a week. Other than that I'm out of ideas!

Anyone?!

this saves my plants life my first grow check it out

http://www.weedfarmer.com/cannabis/tables_guide.php

Thanks man, I've had a look and it seems a lack of K but as I've been feeding them nutes for a week I'm a bit concerned about nute burn?

Thanks again

Going once....!

might be a bit early for nutes - are you growing in soil there? i never added any nutes when growing in soil til they were at least 2 weeks coz it has so much going on already.

now growing in coco i can add earlier but i still make sure it's well diluted for the first wee while

could be a bug as well, i have neem in my coco mix and i love it - bugs hate it, perfect! - good luck