Today's commercial apple trees are never grown from seeds but are clones of trees that possess proven desirable characteristics. Seeds collected from the apples of wild trees will certainly grow, but you really won't have any idea what you'll end up with. Since bees carry pollen from one apple tree to the next, resulting seedling offspring are unpredictable--but the seedlings will most likely be genetically compatible to the climate in the location of the parent plant. It may take six years or more for your apple tree to reward you with edible fruit, which you may find somewhat less than appetizing. If the apples don't taste good enough to you, use them for baking, or making jelly and cider. And all sorts of wildlife will benefit from your wild seed tree and apples, which happily haven't cost you much to produce.
Remove the seeds from the wild apple and dry them for 2-4 weeks. Place them on a piece of wax paper at room temperature and roll them over every day. When the dark color lightens and the seeds take on a dry appearance, they're ready for stratification.
Stratify your apple seeds so that they'll mature enough to break natural dormancy and germinate about three months prior to the last expected frost. A moist chilling period is needed for this. Pack the seeds in a small amount of vermiculite, peat moss or sand dampened with distilled water in a plastic bag. It should be uniformly moist, but not soggy or wet. Close it and store in the crisper of your refrigerator at 35-40 degrees F for three to four months. Open the bag two to three times weekly to circulate some fresh air into it. Make sure the packing medium remains moist.
Combine equal parts vermiculite and peat moss. Fill the cells of a plastic seed starting six-pack with the medium to within about 1/2 inch of the tops. Plant an apple seed about 1/4 to 1/2 inch deep in each. Use a plastic spray bottle to dampen the planting medium with distilled water so that the surface is evenly moist, not soggy.
Seal the seedling pack in a clear plastic bag. This will help retain the high humidity level crucial for germinating your wild apple seeds. Poke a few small holes in the bag to provide adequate air circulation. Set the pack in a warm spot out of direct light. Above a hot water heater is an ideal choice.
Check the seed pack once or twice weekly to make sure the medium remains moist. Germination can take as little as a few days or as long as a few months, depending on the environmental conditions and the seed's genetics.
Move the pack when the seedlings germinate. Set it in a warm spot with as much indirect bright light as possible. Leave the plastic bag in place until the seedlings are about an inch tall because they'll appreciate the humidity. Remove the bag but give the young plants a gentle misting once or twice daily.
Pot the seedlings individually after they've grown at least two sets of leaves. Use the same medium mix that you germinated them in. Make sure that the surface remains evenly moist and continue to provide plenty of bright indirect light for the next two to three months.
Acclimate your wild apple tree seedlings to the outdoors when the weather turns warmer and there's no danger of frost. Set them in a dappled location early in the morning and bring them back inside around noon for a week. The following week you can put them outside in the morning and leave them there until dusk. The week after that, allow your young plants to remain out overnight. The fourth week they can spend mornings in direct sun and afternoons in a dappled location. Thereafter move them into full sun for a week.
Plant the seedlings in very well draining locations in full sun about 30 feet away from each other and 30 feet away from any other trees. Keep them well watered but never soggy or wet. Feed with fruit tree fertilizer according to the manufacturer's recommendations.