Every year, the Washington apple industry learns more about WA 38, the apple marketed as Cosmic Crisp.

As the apple enters its sixth harvest, researchers with Washington State University and the Washington Tree Fruit Research Commission continue to fine-tune their recommendations for harvest and storage.

The key harvest criteria — relying on the cultivar-specific starch scale rating between 2 and 3.5 and a breaking background color — have not changed. But as many orchards enter more mature production patterns, researchers say they see quality differences between young orchards and trees over 4 years old.

The recently published recommendations for 2024 detail these differences and caution that in young orchards, fruit maturity may be inconsistent, greasiness can develop in storage, and fruit from these orchards should be sold in January and February. Mature orchards seem to outgrow these concerns, developing fruit with consistent maturity that can be picked in one pass.

WSU postharvest physiologist Carolina Torres and research commission director Ines Hanrahan prepared the updated recommendations.

The shipping date for this year’s crop is set at Nov. 25. That’s because WA 38 takes about six weeks, on average, in storage to reach its starch clearance targets for optimum flavor. The recommendation is to market fruit from mature orchards in the first part of the season, since it matures more consistently.

The document also details storage and handling recommendations. It can be found online at: treefruit.wsu.edu/article/recommended-harvest-criteria-for-commercial-wa-38-storage-in-2024.

—by Kate Prengaman