Plums and cherries will germinate better after storage for several days at temperatures below 40 degrees F or after a winter outdoors. For apricots and peaches, try gently cracking the hard shells with a nutcracker before planting. Be careful not to damage the kernel, however, for this is a living seed. Plant the stone an inch deep in a damp potting mixture, and with luck, your tree will grow. Just be patient, and don't overwater.
Avocados are always a favorite for kids to grow.
These tend to germinate more readily and grow more quickly. Once you have removed the pit, wash it off, and allow it to dry for two to three days. Peel away as much of the onion-like skin as possible. Suspend it over a glass of lukewarm water using toothpicks, making sure the broad end of the pit is covered by one-fourth inch of water at all times during the rooting period. You don't have to live in Florida in order to grow citrus trees.