help whats wrong with my plants?!?

hey this my first grow heres some pics there in there first week of flowering first week on half strength bloom nutes, is it because my nutes got low nitrogen or is it something else there lacking? all help much appreciated by the way im talkin about the yellowing of the leafs

I wont be cocky and say do a serch since i dont serch my self so here ya go


https://www.rollitup.org/general-marijuana-growing/1469-marijuana-plant-problems-cures.html


Looks like Potassium problems