yes its necessary.....if you're adding nutes salts will most likely build up

the key is to constantly be checking your PH and if its getting out of the proper range you should flush otherwise expect nute lock out
FireTheft Reviewed by FireTheft on . Is Flushing Necessary When Growing Organically? I'm currently growing in Humboldt's Happy Frog, my nutes are Pure Blend Pro Bloom for Soil, Cal-Mag Plus, Bio-Bizz Topmax Bloombooster and very occasional Liquid Karma...many of my grow books recommend a flush every 30 days but i've read on the forum that flushing is not necessary with organic soil grows...if flushing is necessary how often should i flush besides the obvious flush 7-14days before harvest? Thanks in Advance Rating: 5