Growing apples in the home garden can be an enjoyable and rewarding experience, but consistent production of high quality fruit requires knowledge of tree and fruit growth and a willingness to perform certain practices at the appropriate time. Virginia is on the southern fringe of the U. S. apple producing region. Most apple varieties produce the highest quality fruit when night-time temperatures are cool (less than 60°F) at harvest time. Apples grown under warmer conditions tend to be large, soft, poorly colored, and less flavorful than when grown under cooler conditions. Our warm humid summers are also conducive for infection of many diseases. For these reasons, the best Virginia apples are grown at elevations higher than 800 feet above sea level in the western part of the state. However, even apples grown in eastern Virginia usually have quality superior to apples purchased in the supermarkets.
A. Cold Air Drainage - The most important factor contributing to annual cropping is the avoidance of frost during bloom. Air temperatures below 28°F during bloom may kill flowers and eliminate the crop. Covering trees with various materials is of little benefit. In general, high areas such as hill tops or hill sides, that are surrounded by lower ground, have the least frost damage. Cold air is heaver that warm air and flows into low areas much as water flows into low areas.
B. Soil Considerations. Apples grow well in a wide range of soils, but the best fruit quality is produced on moderately fertile soils.
There are more than 3,000 apple varieties in the world, but only about 25 varieties are commonly grown in Virginia. Many varieties perform satisfactorily in Virginia, but some should be grown only at higher elevations, where night time temperatures are relatively low. Generally, apples grown with low (40 to 60°F) night-time temperatures have better red color, firmer flesh, better storage characteristics, and better flavor than fruit grown in warmer regions. Because most apple varieties are adapted to certain climates, local environmental conditions should be considered.
Personal preference for a given variety is an important consideration in variety selection. For example, 'McIntosh'-type varieties perform best in Northern states, but 'McIntosh' grown in Virginia are harvested before northern-grown 'McIntosh' are available in supermarkets. Therefore, Virginia-grown 'McIntosh' are the only 'McIntosh' available. Although the eating quality is only fair, it is acceptable.
Use of the fruit is another consideration. People differ in their opinions concerning the best varieties for sauce, pies, juice, and eating out of hand. Therefore, select varieties you prefer to use for various purposes. Some varieties store better than others and this may be an important consideration.
Apple varieties ripen in Virginia from late-June until mid-November. If desirable, different varieties can be planted to provide fresh apples over a four-month period.
Varieties also differ in susceptibility to some diseases. Fireblight is a bacterial disease that can kill branches or even trees. Varieties such as 'Gala', 'Jonathan', 'Granny Smith', 'Paulared', 'Mutsu','York', and 'Jonagold' are particularly susceptible. Certain new varieties have been bred for resistance to some diseases. These so-called "disease resistant varieties" are resistant to apple scab, and sometimes cedar apple rust, powdery mildew, or fireblight. These varieties were not selected for resistance to the summer diseases, sooty blotch, fly speck, black rot, white rot, and bitter rot. Therefore, these varieties require fungicide sprays to produce high quality fruit.
Table 1 lists the characteristics of some varieties grown in Virginia. For information on other varieties, see http;//pubs.ext.vt.edu/422-760/
|Table 1. Apple varieties recommended for Virginia. Ripening dates are for Blacksburg. Dates for regions east of the Blue Ridge may be 5 to 14 days earlier.|
|Lodi||July 1||F||F-G||yellow-green||tart||stores poorly|
|Earlycrisp||July 13||G||F-G||yellow||tart/sweet||best very early apple|
|Ginger Gold||Aug. 12||E||G||yellow||mild/sweet||stores well|
|Redfree||Aug. 15||F-E||P||red||tart/sweet||best in cool seasons, scab resistance|
|Gala||Aug. 20||E||P||yellow||tart/sweet||best summer apple, very susceptible to fireblight|
|Jonagold||Sept. 8||G||E||green/yellow||tart/sweet||stores poorly, triploid|
|Sept. 16||E||F||red||sweet||leading variety in US|
|Sept. 20||E||E||yellow||sweet/tart||best all-around variety|
|Empire||Sept. 23||E||F||red||sweet/tart||best McIntosh-type|
|Rome||Oct. 12||F||G||red||sweet/tart||large fruit|
|Winesap||Oct. 20||F||G||red||tart||stores well, triploid|
|York||Oct. 20||G||E||red||tart||tastes best after 2 months storage|
|Fuji||Oct. 25||G||E||red||sweet||stores for a year|
|Oct. 25||F||G||red||tart/sweet||tolerates heat|
|z E = excellent, G = good, F = fair, P = poor|
Pollination is the transfer of pollen from the anther of a flower to the stigma of a flower. Insects are responsible for transferring apple pollen. Apple flowers usually will not set fruit when pollinated with pollen of the same variety. At least two apple varieties growing in fairly close proximity (no further than 100 feet apart) will ensure good fruit set. Triploid varieties such as 'Winesap', 'Jonagold', 'Mutsu', and 'Stayman' have three sets of chromosomes, produce nonviable pollen, and are not effective pollenizers. When triploids are planted, two additional diploid varieties are needed to ensure fruiting of all three varieties. The other factor to consider when selecting pollenizers is that the two varieties must have open blossoms at the same time. Crab apple trees within 100 feet of apple trees will usually provide adequate pollination.
Apple trees grown from seed are not the same variety as the tree on which the seed developed. Therefore, to produce more trees of a variety the trees must be budded or grafted onto another apple tree. Certain apple varieties have been selected as rootstocks and varieties are grafted onto these rootstocks. Rootstocks are selected for certain characteristics such as tree size, fruitfulness, and disease resistance. The three general size categories for rootstocks are standard, semi-dwarf, and dwarf, but there is a range of tree size within each size group. Below is a brief description of the common apple rootstocks.
Trees can be purchased locally at garden centers or from fruit tree nurseries. Information on rootstock and variety is often lacking at garden centers: rootstocks are often referred to as "dwarf", but there is no way of knowing which dwarf rootstock is used. Good quality trees of specific varieties, rootstocks, and tree sizes can be mail-ordered from fruit tree nurseries. Large trees and 2-yr-old trees are usually most expensive. Medium sized (1/2 to 5/8" diam., 4 to 6' tall) 1-yr-old trees perform very well. Most reputable nurseries provide free catalogs upon request and have a large selection of varieties on several rootstocks.
Trees purchased in pots are relatively expensive. Garden centers purchase bare-rooted trees and plant them in pots within several months of being sold. These trees often produce no new roots before planting and should be handled the same as bare-rooted trees. March and April is the best time to plant in most parts of Virginia. Bare-rooted trees arrive from fruit tree nurseries in paper bags or cardboard boxes, and roots are packed in moist sawdust or sphagnum moss. Upon arrival trees should be inspected for condition and accuracy of the order. Trees should be rewrapped and stored in a cool place (40 to 50° F if possible) until planting. Make sure roots do not dry out.
Preplant soil preparation. Several months before planting, the soil should be tested. Soil analysis kits can be obtained from your local county Extension office. Apply lime and fertilizer as recommended from the soil test. Lime moves extremely slowly in the soil and, if possible, should be plowed or cultivated into the soil. Also, apply phosphorous and potassium if soil test indicates a need. Because broad leaf plants can be infected with virus, such weeds should be eliminated to produce a solid stand of grass before trees are planted.
Dig holes with a shovel or auger deep enough to set the tree in the hole. Holes 18 inches deep and 18 inches in diameter are usually adequate. Place the root system in the hole, partially fill the hole and tamp the soil to insure root-to-soil contact so roots will not become dry. Fill the hole and tamp the soil. Water the tree with at least 2 gallons per tree. The graft union should appear as a slight bulge or healed wound about 10 to 18 inches above the highest root. Sometimes trees are budded only 4 to 6 inches above the highest root. These trees should be planted so 3 inches of the rootstock is above ground to prevent the variety from rooting. At other times trees may be budded high and there may be 10 to 18 inches of rootstock below the bud union. In this case, plant the tree so the highest roots are about 4 inches below the soil. Where visible, the original soil line on the rootstock can be used as a guide for planting depth. If the variety roots, most characteristics of the rootstock will be lost. Place hardware cloth loosely around the base of the trunk to prevent rabbits from feeding on the bark.
Tree spacing varies with rootstock/varieties combination and soil type. One should also make allowances for the type and size of equipment to be used around the trees. Table 2 gives some general guidelines for determining spacing of apple trees.
|Table 2. Suggested tree spacings for different soil types and variety/rootstock combinations.|
or strong soils
moderately fertile soil
varieties3 or weak soil
|M.9||12 x 18||10 x 16||6 x 12|
|M.9/MM.111||14 x 20||10 x 16||6 x 12|
|MARK||10 x 18||10 x 16||6 x 12|
|M.26||14 x 20||12 x 18||8 x 14|
|M.7||16 x 24||14 x 20||10 x 18|
|MM.106||14 x 22||12 x 18||8 x 14|
|MM.111||18 x 26||16 x 24||14 x 22|
|Seedling||22 x 30||18 x 26||16 x 24|
|1Vigorous varieties include York, Stayman, and Gala.|
2Moderately vigorous varieties include Standard Delicious, Winesap, Rome, and Golden Delicious.
3Less vigorous varieties include spur-type Delicious, Rome, Jonathan, and Idared.
At planting, the tree needs to be pruned to induce proper branching. Some trees from the nursery have branches, some do not. If the tree is a nonbranched whip, cut off the top at 36 inches above ground. If the tree is branched, remove branches lower than 24 inches above ground, remove dead and broken branches, and branches with narrow crotch angles (less than 30° from vertical). Dwarf trees should be tied to wooden post or some type of support when the central leader (top upright extension shoot developing below the pruning cut) is 12 to 15 inches long, to prevent it from flopping in the wind.
Trees should be watered every 14 days unless at least 1 inch of rain fell since the last watering. Use herbicides or cultivation to eliminate weeds and grass within 2 inches of trunk. Organic mulches conserve water and eliminate weeds, but as the material decomposes, nitrogen is released during the late summer when high levels of nitrogen are not desirable. Late-season nitrogen delays the development of cold hardness and causes fruit to be poorly colored and soft. Mulches also provide good habitat for rodents that feed on tree roots and bark. For the above reasons, organic mulches are not recommended for fruit trees.
Fertilize trees twice (2 weeks and 6 weeks after planting) with a nitrogen fertilizer (examples include ammonium nitrate, calcium nitrate, or urea) or a complete fertilizer (10-10-10, 10-20-20, or 5-10-10) at the rate of 0.05 pounds of actual nitrogen per tree per application (1/2 lb. of 10-10-10-, 1 lb. of 5-10-10, or 1/3 lb. of calcium nitrate). To avoid root injury, place fertilizer in a band 6 to 18 inches from the trunk around the tree. Organic forms of fertilizer (manure, blood meal, and bone meal) are not recommended because the nutritional analysis is usually unavailable and the release rate cannot be controlled. High levels of nitrogen are required early in the season, and low levels are desirable during late summer.
During late winter, or early spring within a few weeks before bloom, trees should be pruned. Pruning temporarily reduces tree cold hardiness. Pruning just before bloom, or even during bloom, reduces the likelihood of winter injury.
The central leader will have 2 to 4 narrow-crotched upright shoots developing just below the previous year's pruning cut. Retain the longest straightest shoot and remove the top 1/3 of it. Remove all narrow-crotched shoots below the new central leader. Retain all limbs with wide-angled crotches except those developing within 2 feet of the ground. Upright growing branches should be reoriented to 45 to 60° from horizontal. Branches can be spread by placing stiff pieces of wire or wooden sticks between the trunk and upper surface of the branch. Branches can also be spread by tying the branch down with string or hanging weights on the ends of the branch. Prune as little as possible to encourage early fruiting.
Fertilization. About a month before bloom fertilize the tree with 0.15 lbs. of actual nitrogen per tree (e.g., 1.5 lbs. of 10-10-10, 3 lbs. of 5-10-10, or 1 lb. of calcium nitrate).
Weed control. Control vegetation under the tree, with cultivation or herbicides, for a distance of 3 feet from the trunk.
Prune trees as in the second year. As trees start to fruit, the weight of the fruit may pull branches down and cause the branches to "weep." This situation can be corrected by tying branches up. Another way to deal with the problem, while dormant pruning, is to cut off the dropping end of the branch to a more upright-growing shoot. When the tree attains the desired height, pruning the top of the tree should promote renewal of the branches. First, lower the central leader by cutting into 2-yr-old wood just above a wide-crotched, moderately vigorous shoot. When the diameter of a branch in the top third of the tree is 1/2 the diameter of the trunk at the point of attachment, the branch should be removed. New shoots will develop from around the pruning cut. Remove all of these but one relatively wide angled shoot and, if needed, reorient it to about 40-45° from horizontal. In this manner, branches in the top of the trees will always be young and relatively short and will not shade the lower part of the tree.
Fruit thinning. Trees on dwarf rootstocks may flower and fruit as early as the second or third year. Allowing too many fruit to develop on a tree will have several negative consequences.
Ideally there should be no more than one fruit per spur and fruits should be spaced every 6-8 inches along the branch. To ensure bloom the following year, trees must be partially defruited within four weeks after bloom. Early fruit removal also results in the largest increase in fruit size.
There are two ways to remove excess fruit.
Determining when to harvest apples is not an easy task. The terms "mature" and "ripe" are often confused and will be used in this discussion. The term "mature" indicates that upon removal from the tree, the fruit is able to ripen. The term "ripe" refers to a fruit with acceptable eating quality, and includes texture and flavor.
As fruits mature they soften, the skin on the side of the fruit facing the sun turns red or yellow and the ground color (nonred side) changes from green to greenish yellow, the starch content within the fruit declines, sugars increase, acids decline, and flesh color changes from greenish to white or yellow. Red color is not a good indication of maturity because red color can be influenced by other factors such as temperature, light level, tree nutrition, and drought stress. No single index adequately measures maturity in any given year. More than one index should be used to determine harvest date. A brief explanation follows.
Indices that are mistakenly used to determine harvest date include:
|Variety||Days from bloom to harvest|
Apples can be stored after harvest, but storage characteristics differ with variety. Varieties such as Fuji, Braeburn, York, Winesap, and Arkansas Black usually maintain good eating quality until at least March. Early-season varieties usually keep only 2 or 3 weeks, whereas most mid-season varieties store until early February. Varieties with russetted skin ('Golden Delicious', and 'Gala') will shrivel in storage unless placed in perforated polyethylene bags.
The storage potential is directly related to temperature. Fruits are living tissue. The object of storage is to prolong the life of the fruit tissue. Metabolic processes within the fruit, including respiration and senescence, are slow at low temperatures. The ideal storage temperature for most varieties is 30° F, but some varieties such as 'Liberty' and 'McIntosh' store better at 36° F. If it is not possible to store apples at the ideal temperature, use the lowest temperature available, even 50° F is better than room temperature. Most household refrigerators are set at 45° F. Maximum storage life (maintenance of flesh firmness and flavor) for a given variety declines as storage temperature increases. Cool the fruit as soon as possible after harvest and keep the fruit cool until consumed. Fruits harvested in the morning are relatively cool and can be cooled to the optimum temperature quite quickly.
Physiological Disorders are visual symptoms that occur on the skin or in the flesh, before or after harvest, and are not caused by a living organism. Below is a brief discussion of each disorder along with control measures.
There are many insects and diseases that attack apple trees. Some pests are "direct pests" and damage the fruit, whereas others are "indirect pests" and damage the leaves. Loss of foliage results in poor fruit growth, poor fruit color, low sugar levels, and poor storage ability. Adequate control of these pests usually requires sprays containing fungicides and insecticides 10 to 15 times throughout the season. Because pesticide registrations change, and choice of pesticide and spray timing are critical, a discussion of pest control is beyond the scope of this publication. A list of important insects and diseases and times to spray is found in Table 3. For more detailed information on spray timing and recommended pesticides, commercial growers should purchase VCE Publication 456-419, The Spray Bulletin for Commercial Tree Fruit Growers, and noncommercial growers should purchase VCE Publication 456-017, Virginia Pest Management Guide for Horticultural and Forestry Crops.
Apples are usually sprayed with a combination of insecticide and fungicide, and sometimes fertilizer such as calcium chloride, every 2 to 3 weeks during the season. Below is a brief schedule for pesticide applications.
|Name of Spray||Pests Being Controlled|
|Green tip - green tissue first appears in buds||aphid eggs, apple scab|
|Half-inch green - about 1/2 inch of green tissue protrudes from buds||mite eggs, aphid eggs, apple scab|
|Pink - pink tissue appears in flower buds||mite eggs, aphids, fruitworms, plant bugs, apple scab, rusts, fireblight, mildew|
|Bloom - 50 to 80% of flowers are open||apple scab, fireblight, rusts, mildew|
|Petal fall - flower petals fall from the blossom||white apple leaf hopper, spotted tentiform leafhopper, plum curculio, green fruit worms, plant bugs, aphids, leaf rollers, codling moth, apple scab, rusts, powdery mildew, rots|
|1st & 2nd cover sprays - 2 and 4 weeks after petal fall, respectively||Plum curculio, leafhoppers, codling moth, leafminers, scale, leafrollers, apple scab, rusts, powdery mildew, rots|
|3rd - 7th cover spray - 2 week intervals after 2nd cover spray||leafminers, codling moth, leafrollers, apple maggot, apple scab, powdery mildew, sooty blotch, fly speck, rots|
|Fruit Growers Calendar: Fruit Production is a Year-Round Activity|
|January ||July |
|February ||August |
|March ||September |
|April ||October |
|May ||November |
|June ||December |
Commercial products are named in this publication for informational purposes only. Virginia Cooperative Extension does not endorse these products and does not intend discrimination against other products which also may be suitable.
Reviewed by Tony Wolf, Extension Specialist, Alson H. Smith, Jr. Agricultural Research and Extension Center
Virginia Cooperative Extension materials are available for public use, re-print, or citation without further permission, provided the use includes credit to the author and to Virginia Cooperative Extension, Virginia Tech, and Virginia State University.
Issued in furtherance of Cooperative Extension work, Virginia Polytechnic Institute and State University, Virginia State University, and the U.S. Department of Agriculture cooperating. Edwin J. Jones, Director, Virginia Cooperative Extension, Virginia Tech, Blacksburg; Jewel E. Hairston, Administrator, 1890 Extension Program, Virginia State, Petersburg.
May 1, 2009