Measuring the nutrient needs of orchards should be done by using both soil and leaf (also known as foliar) nutrient analyses. For mature fruit trees, leaf mineral content is a more accurate measure of the nutrient status than soil analyses. Leaf analysis can help determine if additional fertilizers are needed before there are any visual signs of deficiency in the tree. Leaf samples should be taken when most vegetative growth has subsided (terminal buds are set), which for most bearing apple trees happens in late July or early August. For the most part, by the time leaf samples are taken and analyzed there is little that can be done to impact the current season’s crop and next year’s flower buds. Therefore, to maintain optimal performance of your orchard, it is recommended to perform a leaf analysis for each block once every three years to ensure that you are consistently maintaining adequate nutrient levels.