RI Fruit Growers

Growing Apples

Home Fruit Production: Apples

Adapted from Chad Finn and Henry F. DiCarlo
Department of Horticulture, University of Missouri-Columbia

Why plant apples? The challenge! The production of beautiful, blemish-free apples by the home gardener is probably the ultimate of horticultural accomplishments. Success requires some thoughtful planning in selecting varieties and root stocks, locating and preparing the site for planting and establishing a season-long routine for such cultural practices as pruning, fertilizing, watering, spraying, etc.

Disease resistant apple trees for Rhode Island
Spraying apple trees

How many to plant?

Don't go overboard! Three trees may be plenty — no more than six. Remember, growing blemish-free apples requires considerable diligence. Neglecting one spraying may make you miss your goal. In addition, the average home is a poor place to store more apples than can be crowded into the refrigerator.

What kind to plant?

Plant dwarf trees. Regular size trees get too big, and adequately spraying, pruning or harvesting the fruit is impossible. Most regular-size apple trees require up to 10 years to come into production.

Today there is a new look in apples. This "revolution" is the development of size-controlled trees. This means that normal-sized apples can now be grown on convenient, small-sized trees. There are four ways apple trees can be reduced in size:

Select a spur-type variety. Spur-type varieties have a natural tendency towards dwarfing — as much as 25 percent smaller than a regular variety. Most spur types have been discovered as mutations in commercial orchards. Unfortunately, only a few varieties are available as spur types. More will probably appear in the future. Spur-type varieties do not dwarf the trees sufficiently for the home gardener, but they can be used with dwarfing rootstock and interstem pieces as described below.
Use a dwarfing rootstock. Many are available. Some do not dwarf sufficiently. Others have disease problems. Trees on most dwarfing root stocks need some kind of support because of weak root systems. See Table 1.

Table 1. Recommended rootstocks

Rootstock	Dwarfing effect	% of full-size tree	Disadvantages	Advantages
MM 111	slight (20-24 ft.)	85%	Nearly full size; Later bearing (5-6 years)	Drought tolerant; Disease resistant; Longevity; Root anchorage
M-7/7A	moderate (15-18 ft.)	50%	Lots of suckers produced; Staking sometimes necessary	Disease resistant; Stress tolerant; Earlier bearing (3-4 years)
M.26	11-14 feet	40%	Needs to be staked; Not drought resistant	Bears early (3 years)
M-9	full (8-10 feet)	30%	Fire blight susceptible; Needs to be staked; Not as stress tolerant	Small tree; Earliest bearing (2-3 years)

Use a dwarfing interstem piece. This could be one of several of the dwarfing root stocks that are grafted onto a hardy root. This produces a four-part tree: 1) seedling root, 2) hardy trunk, 3) dwarfing interstem, and 4) the variety. The interstem piece alone may not dwarf the tree sufficiently for home gardener purposes, so select only spur-type varieties whenever possible to use with interstem pieces.
Use a combination of semi-dwarfing rootstock and dwarfing interstem. MM 106 rootstock in combination with M-9 interstem works well. Further dwarfing results if combined with a spur-type variety.

What varieties to plant?

There are dozens to choose from. A natural inclination might be to plant popular contemporary varieties or remembered old-time varieties. But why not plant varieties that 1) will be easiest to grow, 2) will provide a greater degree of successful production, 3) will provide fruit when market supplies are naturally low, and 4) will introduce you to some new experiences with apple varieties? Disease resistant varieties do not require fungicide applications and therefore only need 2 or 3 insecticide application.

Planting

When to plant. Early spring (late March or early April) is both a good time to plant apples and also the time when most gardeners have the inclination to plant. Fall planting (mid to late November) is also satisfactory.

Where to plant. Apple trees should be planted: 1) where the soil is reasonably deep and fertile with no claypan (if good soil is not available, bring in some good topsoil and place in a raised bed), and 2) in full sun or where sun is received for six or more hours a day. Apples do not tolerate wet feet; plant on a 6- to 7-inch high berm if necessary.

Preparation for planting. Never let tree roots be exposed to sun and drying winds. After purchasing or receiving trees, unwrap the package and make sure the roots are moist. Keep roots packed in moist sand, peat moss, sphagnum moss or sawdust until ready to plant. Keep the roots cool (but above freezing).

While planting trees, keep the roots in a bucket of water or wrapped tightly in wet burlap sacks.

How to plant. Dig a hole about 2 feet wider than the spread of the tree roots and deep enough to prevent crowding. The tree should be planted at the same depth as it was in the nursery; place a small board across the hole as a guide and position the tree properly. Always keep the graft union a few inches above the final soil line.

Just prior to planting the tree, check the root system. Remove all broken roots and trim out any crossed roots. Shorten long roots to 12 to 18 inches. Use sharp pruning shears.

Place the tree in the hole and spread out the roots. If they appear cramped, make the hole larger. As is sometimes jokingly said, "Don't plant a $5 tree in a 50 cent hole!" Do not use fertilizer in the hole!

Refill the hole with a mixture of good rich topsoil and the soil removed from the hole. Replacing all the soil from the hole with topsoil will create an undesirable "pot" situation. To avoid air pockets, tamp the soil with your foot as the hole is filled. When the hole has been filled to within several inches of the top and the soil has been firmly tamped, pour in 1 or 2 gallons of water. This will help settle the soil around the roots.

Permit the soil to settle for several hours after adding the water. Then place a shovel full, or two, of crushed rock (1/4- to 3/4-inch size — not gravel) around the trunk of the tree in a sort of cone shape. Then fill the hole to several inches above ground level with loose soil, but do not tamp.

The crushed rock serves several purposes: 1) it may reduce the incidence of collar rot disease, 2) it will discourage mouse feeding, and 3) it may help anchor the dwarf tree.

Now mulch the tree(s) with a 4- to 6-inch deep mulch in a 6- to 8-foot diameter circle around the tree. Keep the mulch about a foot from the tree trunk. Contain the mulch with a rock border, aluminum lawn edging or any suitable material. The mulch should consist of shredded leaves (and other shredded organic materials), straw, hay, chopped corn cobs, sawdust or any similar material. A layer of decorative bark may be placed over the mulch to improve the appearance, if desired.

The mulch keeps down weeds, prevents injury to the tree trunk from a lawn mower and is essential on M-9 dwarfing rootstock to moderate high summer temperatures and drought periods that tend to adversely affect the root system.

Each fall (early December) add an additional 1 to 2 inches of mulch to replace that which has decomposed.

Painting the trunk with a diluted latex white paint (do not use oil based paints, they will kill the tree) serves two purposes. It helps to prevent injury caused by the heating and cooling of the bark in the winter on the southwest side of the tree (southwest injury) and it discourages many borers from laying eggs on the trunk.

A 15- to 18-inch piece of hardware cloth can be placed around the trunk to prevent rabbit or mice damage. It can be placed several inches into the crushed rock. As the tree becomes a bit older, do not permit the hardware cloth to girdle the trunks. A special white plastic spiral tree guard with several holes for air circulation may also be used. They are available from any nursery or garden center.

Fertilizing apples

A good general recommendation for fertilizing dwarf apple trees after the first year is to use a pound of 12-12-12 (or similar analysis) fertilizer per tree per year. Apply the fertilizer to the mulched area (or in a 3-foot band under the drip line) and at least a foot from the tree trunk. If high carbon mulches such as sawdust, straw or corn cobs are used, additional nitrogen may be needed. Apply 1/4 pound ammonium nitrate over mulch if tree growth appears weak and pale. Apply in late May or early June.

Because of varietal, soil, mulch and site differences, no two fruit plantings will respond the same. Actually, the amount of fertilizer to use can best be gauged by the terminal growth made the preceding year (see Figure 1). Terminal growth is a brighter color and is found on the ends of the branches. It is the amount of last year's growth. Terminal growth on bearing dwarf apples should be around 6 inches. On young trees it might be two to three times this amount. Growth much above or below this figure would indicate too much or too little fertilizer. Fertilizer applications should be adjusted accordingly. Make all fertilizer applications to apples in early spring before growth starts.

Other cultural practices

Staking dwarf trees. A stake should be placed beside M-9 trees as they have a very weak root system. They also should be placed beside any tree that has begun to lean excessively. Place the stake about a foot away from the trunk. A 2 x 2-inch stake should be sufficient. Point the tip and drive it 2 feet into the soil. Do this at the beginning of the first fruiting year. Secure the tree to the stake by a heavy No. 9 wire and a section of an old garden hose.

Early fruiting. Keep all fruits off young trees during the first two years. It is during this time that the tree needs to grow a framework to support the crop in later years. Permitting apples to bear fruit during the first two years can seriously stunt dwarf trees. The third year a few fruits may be permitted to set, but none on the central leader. From the fourth year on, a normal crop is permitted.

Pollination. The transfer of pollen from the male to the female flower parts by insects (mainly bees) is essential for fruit set. Most apple varieties must be pollinated by another variety. It is, therefore, recommended that at least two varieties be planted. Crabapples usually are good pollenizers for eating apples.

Branch spreading. Branches at a 45-degree angle to the trunk (crotch angle) are stronger, fruit more heavily than upright growth, and fruit earlier in the life of the tree. Beginning in the first year and throughout the life of the tree, branches can be spread to develop good crotch angles. When spreading very young growth, typically in the first year or two after planting, clothespins may be used. As the tree ages, weights, tie-downs, or spreaders may be used to train the branches.

Spreaders can be purchased or home-made. Purchased spreaders are usually variable-length pieces of plastic with V's in both ends. Homemade spreaders may be made by partially pounding nails into each end of pieces of wooden lath and then cutting the heads off the nails. Spreaders are placed at an angle between the main trunk and the developing branch that forces the branch out to the correct angle. Weights are used to pull the branches down to the correct angle. When using weights, don't try to get the branches down to 45 degrees right away as branches spread to 45 degrees today will have a wider angle several days from now after gravity has its effect.

Fruit thinning. During a heavy bloom season, apples commonly set too many fruits. Remove all excess fruits during mid-June. This is after the time of the last natural drop. In thinning, leave only one apple per cluster and space the apples not closer than 6 inches apart. This may remove more than three-fourths of the apples on the tree. Although this practice may seem drastic, it is essential for: 1) good sized apples at harvest and 2) development of fruit buds for next year's crop. When thinning, leave the largest apple in the cluster unless it is damaged in some way. With just a few trees, this operation can be done by hand in a few hours.

Pest control. Apples have many persistent pests. Pests may be controlled through good cultural practices and when necessary chemical control.

Good cultural practices include:

plant on a well drained site; berms and/or tile drainage should improve a poorly drained site.
fertilize properly; excessive, vigorous growth or very weak growth is disease-prone.
prune and train properly; sunlight penetration and air movement are essential for drying the tree off, which will help prevent disease.
prune and remove any diseased or insect-infested fruit or branches; for instance, fire blight is commonly controlled by cutting out branches 6 to 8 inches below the diseased wood and apple scab can often be controlled by raking up and destroying diseased leaves in the fall.
control weeds properly. Weeds compete with the plant for moisture and nutrients and harbor many other pests; use herbicides, a weed barrier type of mulch, organic mulch (not directly on the trunk) or shallow cultivation to reduce weed competition.
plant disease-resistant cultivars when possible.

When cultural control of pests is ineffective or impractical, chemicals often are needed to control the pests. To control pests chemically: 1) use effective chemicals, but those considered safe for the homeowner to apply; 2) apply proper dosages; 3) time sprays properly; 4) obtain thorough coverage of all plant parts. Failure to properly execute any of the above can result in inadequate control of insects or unsuccessful prevention of foliage diseases. Apple spray guide.

By the third year (fruiting year) after planting obtain an adequate sprayer of some kind. A compressed air sprayer or knapsack sprayer is adequate for a limited number of dwarf trees.

Pruning suggestions

If the newly set tree is a single, unbranched whip, head it back about 30 inches after the tree is planted

If the newly set tree is already branched, or if it is the second year after planting a single whip tree, select one or two of the best wide-angle branches at least 20 inches from the ground and separated from each other by 6 to 10 inches. Remove all other branches arising from the trunk except the central leader (trunk). Head back the central leader to 30 to 40 inches and shorten the one or two wide-angle branches selected to 15 to 18 inches.

In the next year, select one or two more wide-angle branches along the central leader, each separated by 6 to 10 inches. Shorten the newly selected branches to 15 to 18 inches. Remove all other branches arising from the trunk, except the selected wide-angle branches and the central leader . A total of three to six wide-angle branches should be selected during the first one to three years after planting. This forms the framework of the tree. Note: In selecting wide-angle branches, attempt to space them around the tree trunk.

Pruning in the fourth and subsequent years will be to: 1) Remove broken or crossing branches, 2). Cut out watersprouts (see Figure 7), 3) Thin out crowded branches, 4) Cut back branches that grow beyond a 5-foot spread or 10-foot height to a strong side branch.

You can train your dwarf apple trees to a trellis, although this is more costly and more difficult to handle than a single, free-standing tree with a stake for support. Plant dwarf trees at least 10 feet apart.

Construct a sturdy trellis, using No. 9 wire or heavier, with end posts well anchored. Four wires should be stretched, the lower wire about 20 to 22 inches above the ground and the remaining wires about 12 to 14 inches apart. Tie selected branches to the wires in each direction from the main trunk (see Figure 8). Remove all branches that do not grow parallel to the trellis wires. Selection of desired branches will take about three years from time of planting. Since varieties have different growth habits, they have to be handled as their habit dictates.

Pruning considerations The two basic types of pruning cuts that can be made on an apple tree include heading and thinning cuts. A heading cut is the type of cut you make when you cut off the tip of the branch or trunk . The purpose of a heading cut is to force the development of new branches. In a thinning cut, an entire branch (small or large) is removed. Thinning cuts help remove excess wood without encouraging much new growth. Typically, homeowners make far too many heading cuts, which lead to a very full and dense canopy that is not ideal for fruit development.

Another technique that is used to reduce the amount of regrowth from a pruning cut is to cut into older wood. Younger, i.e. 1-year-old, wood is more vigorous and will produce more growth when cut than 2- or 3-year-old wood.

All pruning is best done in late February or early March before growth begins. A little corrective pruning each year will keep the trees in good shape.

So now, with an acceptable site (sun and soil), size controlled trees, early varieties, and a good spray schedule, growing quality apples can be a reality for the home gardener!

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