In order to obtain the highest quality fruit, apples, apricots, pears, and plums must be harvested at the proper stage of maturity. Once harvested, proper storage is necessary to maximize storage life.
Apples. 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 flavored. Apples harvested 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.
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 up to 3 to 5 months under optimum storage conditions. The storage life of summer apples is only 1 to 3 weeks.
Small quantities of apples can be stored in the refrigerator in perforated plastic bags. Possible storage sites for large quantities of apples include a second refrigerator, cellar, unheated outbuilding, or garage. Place the apples in polyethylene bags or plastic-lined containers to maintain a high humidity. Apples will freeze when temperatures drop below 30 F. During extremely cold weather, move the apples from unheated storage facilities if temperatures are likely to drop below 30 F.
Apricots. Harvest apricots when the fruit begin to soften and develop their characteristic flavor. Handle apricots carefully to prevent bruising. Fruit should keep for 2 to 3 weeks when stored at a temperature of 35 to 40 F.
Pears. 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 will also be poorly flavored. Harvest pears when the color of the fruit changes from a deep green to yellow green. The fruit will still be firm, not soft, at harvest.
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 pears in a tightly sealed plastic bag. The fruit give off ethylene gas which accumulates in the bag and promotes ripening.
To keep the pears for a longer period of time, refrigerate the unripened pears at a temperature of 30 to 35 F. Pears may be stored for approximately 1 to 3 months. Remove stored fruit about 1 week prior to use.
Plums. 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 temperatures near 32 F.
This article originally appeared in the July 28, 1995 issue, p. 117.