In order to obtain the highest quality fruit, apples, apricots, peaches, pears, and plums must be harvested at the proper stage of maturity. Once harvested, proper storage is necessary to maximize storage life.
Harvest apples when the fruit are mature. There are several indicators of apple maturity. Mature apples are firm, crisp, juicy, well-colored, and good flavored. Fruit harvested too early are astringent, sour, starchy, and poorly favored. Apples harvest too late are soft and mealy.
When harvesting apples, pick and handle the fruit carefully to prevent unnecessary damage. Sort through the apples prior to storage. Remove bruised or cut apples and use promptly. Also, remove apples which exhibit insect and disease problems. Separate the apples by size. Use the largest apples first as they don't store as well as the smaller fruit.
Once harvested and sorted, store the apples immediately. The temperature and relative humidity during storage are critical for maximum storage life. Proper storage conditions for apples are a temperature near 32 F and a relative humidity between 90 and 95 percent. Apple varieties, such as 'Jonathan' and 'Red Delicious,' may be stored for up to 3 to 5 months. The storage life of summer apples is only 1 to 3 weeks.
Harvest apricots when the fruit begin to soften and develop their characteristic flavor. Handle the fruit carefully to prevent bruising. Ideal storage conditions for apricots are a temperature near 32 F and relative humidity of 90 percent. Properly stored fruit have a storage life of 1 to 3 weeks.
Harvest peaches when the ground color changes from green to cream or yellow. When harvesting, handle the fruit carefully to prevent bruising. Store peaches immediately at a temperature of 32 F and a relative humidity of 90 to 95 percent. Peaches can be successfully stored for 2 to 4 weeks.
Pears should not be allowed to ripen on the tree. If the fruit are left on the tree to ripen, stone cells develop in the fruit giving the pear a gritty texture. Tree-ripened fruit are also poorly favored. Harvest pears when the color of the fruit changes from a deep green to a light green. Also, the small spots (lenticels) on the fruit surface change from white to brown. At the time of harvest, the fruit will still be firm, not soft.
Pears should be ripened indoors at a temperature of 60 to 70 F. The ripening process should take 7 to 10 days. To hasten ripening, place the fruit in a tightly sealed plastic bag. Pears give off ethylene gas which accumulates in the bag and promotes ripening.
To keep the pears for a longer period of time, store the unripened fruit at a temperature of 30 to 32 F and a relative humidity of 90 percent. Pears can be stored for approximately 1 to 3 months. Remove stored fruit about 1 week prior to use.
As plums approach maturity, the fruit develop their characteristic color. The fruit of blue or purple varieties ('Stanley,' 'Damson,' and 'Mount Royal') change from green to greenish blue, then to dark blue or purple. The ripened fruit color of other varieties vary from yellow to red. Color, however, should not be the sole basis for harvesting plums. As they ripen, plums begin to soften, especially at the tip end. They also develop their characteristic flavor.
Harvest and handle plums carefully. The fruit can be stored for approximately 2 to 4 weeks at a temperature of 32 F and relative humidity of 90 to 95 percent.
Approximate harvest times for tree fruit cultivars can be found in Pm-453 Fruit Cultivars for Iowa. Keep in mind that weather conditions during the growing season may hasten or delay fruit maturity.
This article originally appeared in the July 14, 2000 issue, p. 87.