How to Grow Granny Smiths

Prepare an area for your apple trees several months before you intend to plant the trees. Sample the soil and send it to your local university extension so the soil can be properly amended. Incorporate large amounts of compost to create a well-draining location. Amend the soil according to your soil test results. Often soils with pH between 5.8 and 6.5 require few amendments because apples are highly adaptable.

Choose young trees with good root systems. Select trees that are no older than 2 years. Look for 2-year-old trees that are 4 to 6 feet tall or 1-year-old whips that are free of damage or insects. Purchase at least two varieties of apples, because apple trees require pollinators. Crabapples can also be used as pollinators for Granny Smith apple trees.

Dig a hole in your prepared area that is about 18 inches deep and 18 inches in diameter for each tree. Set the tree so the graft union is at least 3 inches above the ground, and refill the hole with dirt, tamping the dirt as you fill the hole. Plant a tree with a higher bud union so that the top roots are 4 inches below the soil level. Wrap the young tree's trunk with hardware cloth to prevent animal damage.

Remove all branches that are less than 24 inches above the ground on branched trees, or cut whips off at 36 inches during the first year. Fertilize two weeks after planting and six weeks after planting with a complete fertilizer in a band 6 to 18 inches away from the trunk of the tree. Mulch around the base of the trees, and water at least 1 inch every two weeks.

Prune the tree during the beginning of the second year. Winter or early spring pruning before blooms open is best to prevent injury. Remove all but the best limb that has sprouted below the previous year's pruning cut and any branches with crotch angles below 30 degrees. Cut the top one-third off the new limb that sprouted below the previous pruning cut. Fertilize about a month before blooming with a complete fertilizer. Remove any young fruits that may form.

Continue to train and prune the trees into the third year, but instead of removing all fruits, remove all but one per spur. Leave fruits spaced every 6 to 8 inches along branches. Remove fruits by hand three to four weeks after they begin to form so the tree can divert all its extra energy into making larger fruits.

Check Granny Smith apples in late October for ripeness by sampling a fruit from the tree, since the color of the apple does not change significantly when they ripen. Watch for fruits to drop, as this is another indication that fruits are ripening. Pull upward and outward while rotating the fruit to avoid damaging apples when you pick them. Retain the stems whenever possible to prolong the storage life of the apples.