Children are fascinated by the process of planting a seed and watching it grow into a plant or tree. Many fruit trees can be grown from seeds or pips. Planting the seeds or pips can be a class project that can be taken home, or kept in the classroom. The trees may produce fruit when they mature. The fruit trees can be kept to a manageable classroom size by regular pruning in winter.
Lemon trees can grow to 10 feet, but can be managed through pruning in late winter. Plant lemon pips in potting soil in a small pot. Then cover with the bottom of a clear soda bottle. Citrus pips germinate easily and seedlings appear in about a month. Separate seedlings into different pots and repot into larger pots as the plant grows. Pinch prune the seedlings to create a bushy shape. If you choose to buy a larger seedling, transplant to a large pot that will allow it to grow in the classroom. The lemon tree needs bright, but indirect sunlight.
Apple trees will grow to maturity in about an 18-inch pot for many years with regular watering and feeding. In a classroom setting, lessons can be learned from watching the tree bud, bloom then bear fruit. To start an apple tree from seed, plant apple seeds in multipurpose potting soil in a small pot. Then place the pot in a plastic bag and seal. Place the pot and bag in a refrigerator for about three weeks. This speeds up germination. Remove from refrigerator, and place in a cool spot indoors and keep the soil moist. Transplant the seedlings to the larger pot when they are about 6 to 9 inches tall.
Date palms are ideal in a classroom because they grow slowly and can be enjoyed indoors for many years. However, the tree likely will become too large and have to move outdoors eventually. Date palms can be started from pits. Soak the pits in water for 48 hours, then plant vertically in a small pot. Cover the pot with a plastic bag, and set the pot on a shelf. Once you see growth, uncover the pot and move it to a good light. Transplant the seedings to separate pots when they are about 4 inches tall.