BuildASoil Quillaja Saponaria Extract Wetting Agent Powder 20, 8 oz.BuildASoil customers absolutely love the Quillaja Extract 60 but have been asking for a more cost effective version for soil drenching and more regular use. I have worked with our favorite supplier to offer our most natural version. When the quillaja tree bark is processed for it's saponin it goes through a process that will create a 20% saponin extract with the LEAST amount of processing. This makes the Quillaja 20 the least processed and most