Just dig a wide hole in the existing soil deep enough to accommodate the rootball and plant. No soil amending, no fertilizing and no root booster. Stake only if necessary to protect against high winds. You always want to water a new plant in well and then as often as necessary to keep the soil uniformly moist....not wet. You can use your cotton burr compost as a mulch.

You will need a second apple variety (or a neighbor's apple tree) to get cross pollination and produce fruit.

Thanks so much! We have a crabapple and several neighbors do, so I'm keeping my fingers crossed that they will bloom simultantiously and work as pollinators. If not, we'll have to buy a columnar or espalier too since space is limited.

I amend my soil in the hole and I dig in amendments in about a three foot diameter circle. This will help the tree recover from transplant shock.

If your tree is a dwarf or a semi-dwarf it's recommended that the tree be staked. So you would drive the stake prior to setting the tree in the hole. A pine stake will rot out in about 3 years. The stake should be permanent particularly for dwarf trees.

My neighbors crabapple tree blooms during the entire bloom period for the apple trees I have.

I have lots of deer and they seem to prefer apple trees over any other fruit tree I have here. I fence mine with a five foot fence about the diameter of the 3 foot amended circle that I dug.

I'm not familiar with cotton burr compost, it's not a local crop. If it's a good compost then I'd use it. I use horse or mushroom manure and peat in my clay soil. Mulch the tree to keep weeds and grass from growing under the tree. If you use organics for fertilizer a lot of apple trees will be slow growers, especially on dwarfing rootstocks. So don't be afraid to use a lot

I wish you and your son good luck with his new tree. Hopefully he'll enjoy it for many years.

The above is very old school advice.

Amending planting holes for any woody plant has long been proven to adversely affect establishment, not hasten it.

And only dwarf trees or minis require any sort of permanent staking, if even that. Semi dwarfs do not require it except if in a wind prone location and then only temporarily. And you stake after planting, never before!!

you need to determine the rootstock if possible. Dwarf needs to be staked as noted above. Semi-dwarf, in my experience, does not. Standard does not. In MN (zone 4) dwarf takes 2-3 years to produce, 4-7 years for semi dwarf, and seemingly forever for standard (more than 8 years). I note this so your kid can have a reasonable expectation for when to see apples. I don't amend the soil when planting but I do make the hole considerably larger than the root ball on the tree. Watering is important for the entire 1st year and the 2nd if rainfall is sparse. I mulch all my trees with wood chips. you might consider a soil test as it will tell you if you need specific amendments. crabapples make fine pollinators for apples. deer can be very destructive and they like new, young trees the best. My experience is sprays are only somewhat effective. a fence ring is best. good luck.