need help identifying deficiency/burn

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It has been here for almost a week and it is starting to spread. Can anyone help me identify whether its a burn or a deficiency?

I water once every 3 days
She is grown in MG nute release soil so that might be a factor
she is currently on day 6 of 12/12 yet to show preflowers

burning using MG? Thats odd.

I have no experience with Miracle Grow myself.
but I've read enough about it that I wouldn't use it.
do some searches on your MG and see if anyone has a solution for ya. im sure there are similar cases.
good luck.

i have read that MG is bad for young plants because they tend to burn them but if you got this far without a problem then i doubt its burn from your soil. could just be a deficiency but as far as what its missing i couldnt tell you...

http://www.greenmanspage.com/guides/plant_abuse.html

i use this website to diagnose issues like these