Avocados must be harvested when mature, and then softening occurs once fruit is removed. Maturity is based on the percentage of oil in the fruit. The oil percentage does not change once the fruit has been harvested. To determine if fruit are ready to harvest, clip one avocado off and see if it softens without shriveling. If it shrivels, the oil content of the fruit is not yet high. Another clue is the skin color of the fruit. The skin of green-fruited varieties turns from a green to yellowish-green, and black fruited varieties turn from green to black. You can also cut the fruit open. When the husk covering the kernel inside the fruit is brown and papery, the fruit is ready to harvest.
To harvest, clip the fruit off the tree, leaving just a little bit of stem on the fruit. Avoid pulling the fruit from the stem because it will hasten decay. The fruit keeps best on the tree, so harvest only what you need at any one time. Overripe fruit left on the tree may soften, russet, and crack on the blossom end, providing an entry point for disease organisms or fruit flies to enter.
