How Can Growers Determine Apple Fruit Maturity and Optimal Harvest Dates? (FS-1180) | University of Maryland Extension

FS-1180  |  September 2021

How Can Growers Determine Apple Fruit Maturity and Optimal Harvest Dates?

Whether apples will be sold for immediate fresh market consumption, stored for wholesale under regular or controlled atmosphere storage, or sold for processing, estimating optimum harvest dates is critical for scheduling labor, and ensuring a high-quality product.

Apple tree, Photo: Macarena Farcuh, University of Maryland

Fruit harvested too early will have insufficient red skin coloration, low sugar content (soluble solids), and high acidity levels. The fruit also will be small, too firm, lacking flavor, and susceptible to physiological disorders such as bitter pit or storage scalds. Fruit harvested too late will be overripe, leading to off-flavor, softening, susceptibility to damage and pathogens, short postharvest life, and increased potential for physiological disorders.

Growers can determine apple harvest maturity and optimal harvest dates using different maturity indices, including changes in background and surface color, fruit firmness, starch content, soluble solids content, acidity levels, and fruit taste. A good strategy is to use several indices to make harvest and storage decisions, especially under unusual weather conditions. No single maturity index alone can explain true maturity and the values of each maturity index can differ from year to year.

Cultivar/strain, orchard block, and the fruit’s target market will determine the appropriate maturity indicators and value ranges to use. The maturity indices will vary for each cultivar/strain and orchard block, so it is important to collect representative samples from each to conduct the maturity tests. Start monitoring fruits weekly around 4 to 5 weeks before the anticipated normal harvest date. Careful observation of the results and trends in each cultivar/strain and orchard block will help you identify the best indices to use for determining optimal fruit harvest dates. This report describes several tests to determine apple fruit maturity. Before performing any measurements, however, the first step is to know how to collect a representative fruit sample from the orchard block.