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.