How We Determine When to Harvest Apples

Have you ever wondered how growers know when it’s time to harvest their crop of apples? With apple season upon us in central Washington (and other parts of the country as well), I thought I’d share some of the tests and information that growers turn to in order to estimate the perfect time to handpick each apple from the tree.

Bloom Dates: Each orchard location and apple variety has a slightly different window when it blooms in the spring season. Traditionally, apple blossom happens in late April and early May in Washington State, although the past few years it has trended earlier because of the arrival of early spring weather. The dates the trees are in bloom at a particular location gives growers insight to predict when they will actually begin harvesting that particular variety of apples. One fun fact about apple bloom is that the beloved Pink Lady® apple variety is the first to bloom, but the last to harvest!

Sampling: As the predicted harvest window draws near, and apples begin to look ready to pick, growers work with our field staff to collect samples from various trees in a particular orchard and to gauge maturity. The sample of apples is tested by our Quality Control team for its pressures, sugars, starch content, watercore, and in some varieties, acids. The results from these tests help the grower devise a harvest plan. Samples are usually taken from at least 5 different trees in uniform locations in the orchard and done at least once a week leading up to harvest, although it’s not uncommon for it to happen more frequently. As you can imagine, many apples are tested to determine when to actually pick!

The Starch Test: One of the tests used to determine when to pick apples is known as the starch test. It’s a great indicator of fruit maturity. A sample of apples is picked from the tree, based on a range of what we think is immature to mature. The fruit is cut in half to reveal the “star” that the core and seed pockets make. The top of the fruit remains to compare color to maturity. Then, iodine is misted onto the apple. Starches in the fruit turn black and sugars remain white. Apples with more starch reserves can be kept in controlled atmosphere storage longer as it takes them longer to convert those starches to sugars when compared to those with less starch reserves. You can read more about how we store apples to learn why you can enjoy crisp and juicy apples most months of the year! A picking schedule is chosen once the starch and sugar levels – and ideally color – align with the grower’s picking strategy.

Determining when to harvest apples is a combination of experience, data collection, and science, and something that our growers use year after year to determine when this season’s crop of apples comes off the tree.


Comments

2 Responses

  1. When I first tasted Pink Lady apples several years ago, they were smooth, tart, and sweet; and I usually had to wait until October or November when they began to show up in our stores in the Midwest. Now they seem to be found year-round, but are not near as flavorful. I also notice that the apples, though shiny (as though fresh) are somewhat pitted. Years back, I thought that was a sign of aging of the apple, and less tasty.

    Then I read somewhere that apples can be stored for as long as a year before they even make it to the grocery store shelves. Unless I’m actually in Washington state, how can I determine the age of the apple that I buy? (Note: I was able to buy some out there last year while I was visiting my sister, and they were as awesome as I remember.)

    Thanks
    Noella Thomas
    Bolivar, Missouri

    • Hi Noella, thanks for your note. It’s true that the season for Pink Lady has expanded and that apples are harvested in the fall but available year-round thanks to storage. However, they should be consistent in flavor and eating experience no matter when you buy them! (Read more here: https://www.stemilt.com/faq-facts/storing-apples-pears/)
      I do believe you’ve just run into some poor-quality fruit as of late and expect that to not be the norm! We grow lots of great tasting and looking Pink Lady apples all year long. In fact, I love this particular apple in the summer because of it’s great flavors. Hope this helps.


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