One thing I don’t see mentioned, is that if you plant an apple this way, the apple tree that grows is very unlikely to be the same type of apple you planted (and could very well taste terrible). This is because the genetic material in an apple seed is derived from both parents. One being the apple tree the apple grew on, the other being the source of the pollen that pollinated the apple blossom. This is why apple orchards graft their apple trees, i.e. take a twig from the tree of a desired apple variety and attach it to a young tree that is already growing. This ensures that the new tree will produce the type of apples you want, not some random apple variety that may not taste good once the tree finally starts producing apples years later. Thats a long time to wait to be sorely disappointed. But who knows, maybe the new variety you make tastes great.