Mid-summer leaf analyses are commonly used as the standard method worldwide to assess the nutritional status of fruit trees. It may be too late to correct nutritional disorders by mid-summer. In this study, reference values that will be used to evaluate the nutritional status of apple trees early in the growing season were derived. To determine the reference values for all sampling periods, the regression curves were created by using the reference values of each period. Correlations were examined between the sixth period and earlier sampling times. The presence of statistically significant correlation coefficients was interpreted as leaf analysis can be used to determine the nutritional status of apples in the early season. It was concluded that leaf analysis can be carried out anytime from commencing two weeks after full loom to lasting 98 days after full bloom for all elements except Iron and Cupper.