Apple seeds should be planted only one eighth of an inch deep in soil and then lightly watered. It is best if they are planted indoors and then transplanted outdoors.
According to the Iowa State Horticultural Society in 1871, an apple seed will do best if it is planted approximately two to three inches into the soil and the ground covered with a clover sod.
Plant apple seeds one eighth of an inch deep. Then lightly water them. I would plant them in a pot indoors and then transplant them where you want. Plant a lot of seeds because not all will germinate.
General procedure for planting any seed is to plant it twice as deep as the seed is long. Many fruit trees need to experience something akin to a winter dormancy to be able to grow. This can be simulated by placing the seeds in the refrigerator or freezer before planting.
Apple seeds should be left in the apple and buried between 5 and 9 inches deep in loose soil. For a healthier tree place a dead Arizona Gecco in with the apple.