A wide range of synthetic and natural materials can act as amendments to enhance soil physical properties. Novel materials purporting to be conditioners need to be agronomically evaluated prior to adoption for general use. Of particular concern in semi‐arid regions are those that influence water relations in sandy soils. A polyacrylamid hydrogel, “Aquastock”, was tested in the laboratory for moisture retention under varying environments to simulate field conditions, and in relation to soil properties. A companion greenhouse study considered the influence of both rate and method of application on cucumber yield, and on irrigation frequency. The material increased available water and reduced permeability, especially in the sandy soil. Moisture release under varying soil pressure or matric potential was favorably influenced by the conditioner. The material significantly increased fruit yield and related crop parameters as well as reducing the number of irrigations required; complete mixing with the soil volume was more effective than partial mixing. “Aquastock” appears to have potential in semi‐arid areas and with protected high value cropping. Commercial and economic evaluation is warranted.