Lignosulfonates (LS) are a by-product of the wood pulping process and have many commercial uses including the production of concrete/cement & plasterboard, a dispersing agent in pesticides & of course a nutrient carrier for liquid fertilizers. There appears to be three main areas where LS is getting a bad wrap. Firstly the high molecular weight (or particle size) in many LS is seen as unsuitable for foliar uptake through small cuticular pores. Secondly, often tissue or sap analysis levels seem to indicate LS performs worse than sulfates. And finally the chelating strength (or stability constant) of LS is lower than synthetic chelates (eg. EDTA) & therefore it’s assumed they are less effective.