In Perth, if the level of phosphorus is greater than 100 ppm, it is not necessary to apply superphosphate. If the level is greater than 50 ppm, reduce the application of superphosphate. Trace elements are normally only needed every two or three years. A suggested trace element mix is given in Table 1. Some nitrogen and potash may be applied with the superphosphate and trace elements before planting or all can be applied through irrigation water after planting.
Sandy soils require frequent applications of nitrogen and potash during the life of the crop.
Loam and clay soils will need lower rates of nitrogen and potash. Table 2 provides a guide to quantities and the frequency of fertiliser applications for Perth and the south-west. Nitrogen applications should be heaviest in autumn to encourage the production of large crowns, and lowest in spring as nitrogen has adverse effects on fruit quality. Avoid heavy nitrogen applications just before or during the heavy fruiting period. Strawberry growers on heavier soils in the south west may prefer to use blood and bone before planting.