A number of factors will help you determine if fruit is sufficiently ripe for harvest. Keep in mind that “tree ripe” fruit is great to eat but will not keep long and the quality will diminish quickly. If you intend to store fruit for a time through freezing or “home canning,” you should consider harvesting it at the firm ripe stage rather than tree ripe.
One of the best places to start when determining fruit ripening is to know the characteristics of the particular variety you have. Nurseries can generally provide you a list of fruit trees in order of ripening. When selecting trees for a home orchard, this list can help you choose the varieties that will best meet your needs. For example if your desire is to have enough fruit to home can then you should choose varieties that ripen at about the same time. If you desire is to have a smaller amount of fruit throughout the season then choose several varieties that ripen at different times.
Fruits that contain a pit such as peaches, apricots, and nectarines go through a “final swell” the last 2 weeks prior to harvest. During this time fruit size increases rapidly, the flesh begins to soften and the fruit becomes sweeter. The outside skin color also changes, turning from green to more red and yellow. The shaded side of the fruit (facing the ground or to the inside of the tree) will also begin to turn from pale to more of a cream or yellow color.
Apples and pears will also change in their appearance as they begin to ripen. Apples in particular will take on their “fall color” and the red and yellow pigments will become more noticeable. Internal seed color will begin to turn dark and the fruit will begin to soften.
European pears will not ripen while on the tree, and should be harvested and stored for several days to complete ripening. As pear fruit approaches ripeness, the small pores on the fruit surface (lenticels) will turn from white to brown, the peel color becomes lighter colored, and the fruit will begin to loosen at the stem during the final stages of ripening. Asian pears stay firm when ripe and will ripen similar to apples.
Apple and pear fruit should come loose from the branch with a gentle lift and twist. Picking the fruit by pulling down will break the fruiting spur. Many homeowners have the mistaken notion that winter apples aren’t properly ripe until they have been frozen. The conditions that result in ripening are cold nights (not freezing) and sunny days. Ripe apples will freeze when the fruit temperature is about 28 F. Once frozen and then thawed, apple tissue will begin to break down rapidly. If fruit freezes on the tree before you can pick it, it may not be a total loss. Wait until the fruit thaw on the tree, then pick and eat or process (juice or sauce) as quickly as possible.
To maximize the post-harvest life and quality, ripe fruit should be harvested when temperatures are cool, or the fruit is cooled as soon as possible after harvest.