Goofy:

Apple seeds require a period of cold treatment to enable the embryos to break dormancy. Put the fresh seeds into a ziplock bag with a barely moist piece of towel paper, place them in your refrigerator, then check them on a weekly basis. They should begin to sprout in about 3-6 weeks, but that period is not set in stone. After you see them sprout, that is the time to put them in your pots.

I hope you have a lot of room, a lot of time, and low expectations if you are going to grow out a seedling apple or two. Seedling trees will grow very large, and take a long, long time to bear. When they do, the apples may not resemble McIntosh at all. Chances are pretty good they will be small, sour, and resemble crabapples. That's the reason apple trees are grafted - so they will be copies of their parents.

If you want a McIntosh tree, buy a grafted specimen from a good nursery source. Some pretty good nurseries sell grafted trees on semi-dwarf rootstocks for about $10. Even the more expensive nurseries wouldn't run much over $20, and it would be money well spent.

Don Yellman, Great Falls, VA

McIntosh is a great tasting apple but has serious defects and that is why it doesn't show up much in retail. Very easily bruised soft fruit. suc. to scab, and only fair shelf life. I think it has one of the best flavors, quite unique to McIntosh but if you want to save seeds, I would at least do a controlled cross to McIntosh from another Apple variety that has qualities lacking in McIntosh.
I would try pollen from a good keeper apple with more disease resistance. Perhaps Roxbury Russet or Prima?

Here is a link that might be useful: Good scab-free apple pollenizers