Small fruits, such as raspberries, are highly perishable. Harvesting the fruit at the right stage of maturity and proper storage are vital to insure high quality. If possible, harvest in the early morning hours before field heat builds up in the fruit. Small quantities of fresh fruit can be stored in the refrigerator for a short time. Surplus fruit should be canned or frozen. While personal preferences vary somewhat, the following criteria should help you decide when to harvest the small fruit crops at their peak of quality and flavor.
Harvest blackberries when the fruit develop their characteristic black color and flavor and become soft. Harvest every 3 to 5 days. Blackberries can be stored for 2 to 3 days at a temperature of 31 to 32 F and a relative humidity of 90 to 95 percent.
Do not harvest blueberries until fully ripe. The best indications of ripeness are color, flavor, and picking ease. Fully ripe blueberries are uniformly blue in color, have a good flavor, and separate easily from the plant. Blueberries should not be harvested by color alone as the berry is often blue for some time before being fully ripe. After harvesting, store blueberries at a temperature of 31 to 32 F and a relative humidity of 90 to 95 percent. Maximum storage life is 2 weeks.
Fully ripe currants are slightly soft, juicy, and develop the characteristic color of the variety. Most currant varieties are red at maturity, a few are white. For jellies and jams, pick the currants when they are still firm and not completely ripe. Harvest currants by picking the fruit clusters rather than the individual berries. After picking, the individual berries can be stripped from the stems. Currants can be stored in the refrigerator for 1 to 4 weeks. Optimum storage conditions are a temperature of 31 to 32F and a relative humidity of 90 to 95 percent.
Fully ripe elderberries are plump, slightly soft, and dull purple in color. For jelly, harvest the berries when only half ripe. Elderberries are borne in large, flat clusters. The berries mature in mid-summer. Elderberries can be stored for 1 to 2 weeks at a temperature of 31 to 32 F and a relative humidity of 90 to 95 percent.
For jams, jellies, and pies, most gardeners pick gooseberries when they have reached full size, but are not fully ripe. At this stage, the fruit are green, tart, and still quite hard. Others prefer to allow the fruit to ripen to a pinkish color and sweeter flavor. Gooseberries can be stored for 3 to 4 weeks at a temperature of 31 to 32 F and a relative humidity of 90 to 95 percent.
Color, size, sweetness, and flavor are the most useful indicators of grape maturity. Depending on the variety, berry color changes from green to blue, red, or white as the grapes approach maturity. Color alone, however, should not be the sole basis for harvesting grapes. The berries of many varieties change color long before they are fully ripe. At maturity, individual berries are full size and slightly less firm to the touch. As a final test, taste a few grapes for sweetness when berry size and color indicate the fruit is approaching maturity. Harvest grape clusters when the berries are sweet. When harvesting grapes, remove clusters with a knife or hand shears. Sound grapes can be stored in perforated plastic bags in the refrigerator for up to 2 months. Optimum storage conditions are a temperature of 31 to 32 F and a relative humidity of 85 percent.
Raspberries are ripe when the fruit is fully colored. Also, ripe berries slip easily from the receptacles, which remain on the plant. Raspberries are very perishable. They should be harvested every two or three days, handled carefully, and refrigerated or frozen immediately. Maximum storage life is 2 to 3 days at a temperature of 31 to 32 F and a relative humidity of 90 to 95 percent.
Strawberries are fully ripe when uniformly red. Pick the berries with the caps and stems attached to retain firmness and quality. Pinch the stem off about 1/4 inch above the cap. Don't pull them off. Strawberries should be picked about every other day in warm weather, every 3 to 4 days in cool weather. The harvest period for some June-bearing varieties may last three to four weeks. Strawberries can be stored in the refrigerator for up to 5 to 7 days. Optimum storage conditions are a temperature of 32 F and a relative humidity of 90 to 95 percent.
When harvesting small fruits, pick and the handle the fruit carefully. Rough treatment during harvest will damage the fruit and reduce its storage life and lead to greater spoilage.
This article originally appeared in the June 7, 2002 issue, pp. 75-76.