Solid surfactant-impregnated, water-soluble fertilizer compositions are disclosed together with aqueous concentrates made therefrom. The use of dilute aqueous compositions made from said concentrates to enhance the rewetting of water uniformity and nutrient retention characteristics of initially untreated plant culture media is also disclosed. The fertilizer composition solids are friable and are composed of from 65 to 99 weight percent water-soluble fertilizer; and from 1 to 35 weight percent of a surfactant system comprising water-soluble nonionic surfactant and alkyl polyglycoside in a weight ratio of from less than 2:1 to 1:5. When these solid compositions are dissolved in water to form concentrates having from 20 to 50 weight percent fertilizer, the concentrates are both single phased and extremely stable.