>>2574650First, some trivia.
It usually takes about a dozen of years from starting a seedling to its first fruit.
You need enough space to grow multiple trees to get one that tastes good.
These issues are what deters most people from growing apple trees from seeds. If you have space and patience – go for it.
If you don't have space & patience, then do graft them.
And yes, cross-breeding nice trees yields better results.
Grafting apple trees is easy. You can graft a 1 year old sapling in late winter / very early spring (splice grafting). Don't aim for budding, not worth waiting for when you use a generative rootstock. Keep in mind that random rootstock will likely produce a full-size tree (rather than semi-dwarf or dwarf one), and you might need to wait longer for fruits.
> turning these little apple boys into treesGrowing apple trees from a seed is easy; they survive as long as they don't get overgrown by weeds and have sufficient water.
Any standard means for helping plants grow works for them. Calamities such as rabbits are not apple-specific.
> Will I get a deep taprootThe root system is genetically conditioned and does not really depend on growth condition.
That is one of the reasons why most apple rootstocks are vegetatively propagated.
By the way, why are your seedlings diicotyledon? True rebel apple seedling are tricotyledon! :)
(Or rather, were rebel. Now they are Cox's Orange Pippin.)
