CORVALLIS - There are hundreds of varieties of apples grown in Oregon, from old heirlooms to modern disease-resistant cultivars. But often apple tree owners don't know what kind of apple tree they have, much less recognize when their specific type of apple is at its peak of perfection and ready to harvest.
Here are some hints to help those with apple trees figure out what to do, from the Oregon State University Extension Service.
Any given variety of apple reaches harvest maturity at about the same time each year. So keep records for each of your trees, even if you don't know the variety name.
In districts with cool growing seasons such as in the mountainous regions of Oregon, the fruit usually matures later than in the warmer districts, such as in southern Oregon. Within a district, the time of maturity varies slightly from season to season. The most important factors affecting the time of maturity are variety, growing district and the type of growing season it was during the current crop year.
Oregon State University horticulturists classify Oregon into tree fruit ripening districts:
Early - Jackson County, Milton-Freewater and Wasco
Midseason - Lower Hood River, Malheur, Douglas County and Josephine County
Mid- to late - Willamette Valley
Late - high mountains and plateaus and the coast. Early districts often begin harvest about 10 days earlier than midseason districts, and late-season districts about 10 days later.
There are also other clues you can use to determine when apples are ready to pick, including color, ease of separation, fruit drop, softness and flavor. Also, location on the tree may matter. Fruits on the southern side of the tree often ripen sooner than those that get less sun.
Color. Color, both outside and under the skin, is a useful indication of maturity. Apples may be yellow, red, green or combinations of these colors at harvest. When the green has almost completely given way to yellow, a yellow variety is mature. With red blush or striped apples, the area where there is no red color usually changes from green to yellowish at maturity.
The newer red strains are confusing, because they are red all over long before maturity. In these, the change of flesh color (between skin and core) from greenish to white signifies maturity. The greenish color of spur-type Red Delicious may disappear only after several months of storage.
Ease of separation. Unless a "stop-drop" spray has been applied, mature apples are rather easily separated from the tree. Do not pull the apple down to pick it-rather, twist it upward with a rotating motion.
Fruit drop. When a few sound apples drop to the ground, the apples on the tree are nearly mature.
Softness and flavor. When an apple becomes slightly softer and tastes sweet and juicy, it is mature. Some varieties, such as Delicious, become sweeter in storage.
Maturity dates for many of the commonly grown apple varieties in Oregon are given in OSU Extension's publication Picking and Storing Apples and Pears, FS 147.
You may order a printed copy of FS 147 online or by calling 1-800-561-6719. The cost is $1.00 plus shipping and handling.