Do yourself a favor and use a good commercial flushing product. If you are close to harvest (I don't think you are, I think you should go another 3 weeks or more) then stop feeding (N) now. It will force the plant to use up the stored chlorophyll and improve the taste and reduce the cure time. If you are planning on going another 3 weeks then the last week you use the flush product to remove the chemical taste and unused nutrients. Only the trichomes can tell you when the proper time to harvest is.