How is it too late to switch to organic. Give a nice watering til runoff to wash out the salts. I told someone do that mid grow and his plants came out great. If you aren’t an experienced grower, bottled nutes can be difficult. Getting his soil right can definitely save them plants.
OK, I realize this thread is turning into an organic thread, but did anyone notice the OP never mentioned organics?
Dude is just trying to save his/her grow.
It's great that there are people here who give back their experience and their knowledge, from all corners.
But he'll be in week 7 of flower by the time this thread dies LOL. You're not rebuilding soil or changing your environment in that time.
So get your plants some nutrition that they need. Finish your grow.
If you were bleeding and the doctor told you your cut would heal in 3 weeks, or he/she could stitch it right now to assist, what are you gonna do?
Next time, if so inclined, build a soil. It's fun. You can get great results.
Or don't and use bag soil and bottled nutes and get great results too.
In my experience you don't need triple series, or terpenators or bud candies ... or molasses or castings or compost ... just simple macros and micros along with some microbes. But that's me. Doesn't make me a better grower than the next person. Just makes me happy, and successful.