Peaches that are mature enough to pick are still hard. They do not give when lightly squeezed. However, these peaches will ripen off the tree and will have very good quality. They may not be quite as sweet as a tree-ripened peach but are still very good. So what do we look for to tell if a peach is mature enough to harvest? Let’s look at a couple of factors.
Color: The reddish coloration is not a good indicator. Look instead for what is called the “ground color.” This is the part of the peach that does not turn red; for example, around the stem. The ground color of the peach will lose its greenish tinge and turn yellow when the peach is mature enough to harvest. I use this characteristic more to determine when NOT to pick a peach. If there is any green in the ground color, it is too early. If the ground color is yellow, then I move to the next characteristic.
Ease of Removal: A mature peach will separate easily from the branch if the peach is lifted and twisted. If it doesn’t, it is not mature enough to pick yet. All peaches will not be ready to pick at the same time. Pick only those that are ready and come back later for more. It often takes 3 to 5 pickings to harvest a peach tree.
Peaches that are picked early but will be used for fresh eating should be allowed to ripen inside at room temperature. Once they are ripe, they can be refrigerated to preserve them for enjoyment over a longer period of time. (Ward Upham)