Apple trees are one of the most common fruit trees grown in home landscapes. There are many different cultivated varieties, or "cultivars," of apple trees, many of which are grafted onto root stocks and come in a wide range of sizes. Apple trees are available on either standard-sized root stocks or dwarf ones. Apples also come in a variety of colors, flavors and textures, some of which are best for use in cooking and others for eating fresh. Depending on the cultivar, the apples may ripen as early as mid-summer or as late as fall. All apple varieties require a compatible apple tree variety to be planted near them for cross-pollination and proper fruit production.
Water your newly planted apple trees deeply once or twice each week to soak the soil around the root ball when rainfall is less than 1 inch. Water established apple trees deeply and thoroughly once per week in the absence of rainfall.
Feed your 1-year-old apple tree 1 lb. of 10-10-10 NPK (Nitrogen-Phosphorous-Potassium) formula fertilizer in late winter or early spring, before new growth emerges. Feed the apple tree 2 lbs. of fertilizer in the second year, 3 lbs. in the third year and so on, up to 6 lbs. of fertilizer for mature trees. Spread the fertilizer granules over the entire root area of the apple tree, keeping the fertilizer about 6 inches away from the trunk.
Spread a 2- to 3-inch-thick layer of mulch on the ground around the entire canopy area of the apple trees to control weeds and retain soil moisture. Pull the mulch about 12 inches away from the trunk in the fall.
Train your apple tree during the first year by selecting the strongest four to six lateral branches and pruning away all other lateral growth from the main stem. Ensure that these main lateral, or "scaffold," branches are spaced 18 to 24 inches apart and are not directly across from each other on the trunk. The lowest scaffold branches should be two to three feet above the ground.
Insert toothpicks or clothespins in the crotches of the branches to train the branches to grow more horizontally. You'll want to train the apple tree branches to grow at a 50- to 60-degree angle. This will encourage the apple tree to flower and produce fruit sooner.
Prune your apple trees once each year in late winter or early spring while the trees are still dormant by cutting the central stem back to 20 to 28 inches above the highest scaffold branches. Prune away any diseased or damaged growth.