Black inside leaves, outdoor vegging HELP

I'm about 5 weeks into an outdoor grow. I'm using blueberry clones (female), and until about three days ago they were prospering and growing amazingly. Recently the inside of the leafs started turning black, and this appeared first in one then soon after in the plant directly next to it.

I'm aware that pictures help, and they will be up tomorrow but please help me rule anything out tonight.

It might be mold because it has been raining the last 20 out of 30 days.
It also looks like it could be to many nutes, which is possible because i feel that I made the soil mix too strong
It also has the spotting effects like in a phosphorous deficiency

Any ideas on what it could be. Pictures will be up tomorrow but please try to help me tonight.

I HAVE THE SAME PROBLEM! it looks like dark blue spots on the new growth , ive been looking arround to find the problem
and i also think the exessive rain might be the colprit,, let me know if you find out & il do the same!
PEACE