DrGanjanswered grow question 5y ago You've burned out your chlorophyll most likely mate. Not much chance of getting it back now. However, if it's your whole plant yellowing, it could be a nitrogen deficiency which can be quickly amended using a foliar feed. (can use some veg nutes at 1/5th the dosage you would usually use or can buy special stress treatments such as Madame Grow Lavacal Stress Treatment)