IMO I wouldn't give anymore nutrients, Just water you don't want the Nuets in the plants when you chop them they should be flushed out and clean, I was wondering if your Humidity is high in your grow area, It just looks that way to me try to get it down to below 50% if you can. They look ok but seem to be turning brown like you say, and the humidity is my concern. if your RH in your room is lo I really don't know what else could be turning them brown.
You only have one week left?
Hopefully they will be done in a week or two at the most.
Good Luck Hope they turn out for you.