FAQ | Production Horticulture USU

    FAQ

    Climate

    The tendency of home gardeners is to think of their local climate in terms of USDA cold hardiness zone. Hardiness zone is based on the average coldest temperature of the year, and Utah gardens range from zone 3 to zone 9. Certainly, cold winters limit growing many fruit crops in Utah such as citrus, and other subtropical and tropical fruits. However, although mid-winter cold temperature is important, it is usually not the major limiting factor for growing temperate climate fruit species (apple, pear, peach, cherry, etc.) in Utah. Spring and fall temperature fluctuations are more often the climatic factor that limits the success of fruit crops. For example, apricot trees are quite cold hardy and will survive and grow in regions with relatively severe winter temperatures. However, in stone fruits, apricots are among the first to bloom and the developing flowers are frequently damaged by spring cold temperatures. In many colder spots in Utah, apricot trees may only produce fruit 1 in every 5 or 6 years. Under these climatic conditions, the utility of apricot trees becomes limited to shade.

    The length of the growing season is critical to selecting suitable fruit crops. One useful measure of the growing season is freeze-free days, which is the number of days between the average last spring freeze and the first fall freeze. Late season apples, including Granny Smith and some strains of Fuji, will not ripen in many areas, as the growing season is too short.

    Some fruiting species and varieties are severely stressed when daytime temperatures consistently exceed 95 to 100 F. One example is summer-bearing raspberries where the fruit ripening season corresponds closely with the onset of mid-summer heat. Weak, sickly plants and misshapen and bleached fruit are the frequent result of this heat stress. Honeycrisp apple is another example of a variety that is extremely cold hardy but not well adapted to the midsummer heat of the warmer regions of Utah.

    Information on climatic conditions for your region is available from the Utah Climate Center . However, climatic conditions can vary dramatically within a given county or town, and the microclimate can even vary by location in the garden. Factors that affect microclimate include elevation, slope, and the presence of moderating factors.

    Many of Utah’s valleys experience “inversions” in the winter and spring. Under calm conditions and clear skies, a temperature inversion forms when the cold air settles to the lowest spots, displacing warmer air. Historically, the most successful sites for growing fruit along the Wasatch Front were on the east bench. This elevation escaped the coldest midwinter temperatures, and was less prone to spring frosts during bloom. However, this elevation advantage can be lost when cold air cannot “drain” and pools up behind hedges or other obstructions (see figure).

    When strong temperature inversions form during critical stages of flower bud development, some commercial orchards run large fans that mix the air, displacing cold air near the ground and bringing warm air back down into the orchard. Home gardeners in low-lying areas are going to have more risk of spring frost, and should select late-flowering species or may need to forego planting fruit trees.

    Sites with southern exposure, including areas that slope to the south or are on the south side of a wall, fence, etc., intercept more sunlight in the early spring and late fall This warms the plants and soil causing earlier spring growth than sites with northern exposure. Similarly, western exposure sites receive more of the late afternoon sun and experience longer growing seasons and higher incidence of midsummer heat damage than locations with eastern exposure.

    Soil

    The best soils are well drained loam soils with organic matter of 2% or more. For most fruit crops, the soil pH should be between 6 and 7.5. Before planting your orchard, take a soil sample and have it analyzed. The Utah State University Analytical Lab offers several levels of soil testing. The test “Routine plus Micronutrient” is suggested prior to planting fruit crops. (For instructions on soil sampling and testing see the USU Extension Bulletin “Frequently Asked Questions About Soil Testing”. The soil test results will tell you the soil pH, organic matter content (%), salinity, and an estimate of plant available phosphorus and potassium. It is best to submit your samples the year before you plan to plant. This allows time to add organic matter and phosphorus and potassium fertilizer if recommended by the soil test.

    One common mistake gardeners make is not preparing the soil early enough before purchasing trees. It may take a year to prepare a site. Follow soil test recommendations for amendments. Add organic matter such as well-rotted manure, compost, leaf litter, etc. Organic matter will make the soil more friable (loose and crumbly). Work the organic matter into the soil to a depth of about 6 inches. This is also the best time to control perennial weeds such as quack grass, common mallow (cheese weed), Canada thistle and field bindweed (morning glory).

    If soil salinity is high, the site may require application of excess irrigation water to leach away these excess salts before fruit crops can survive and thrive (See table below). After orchard establishment, correcting problem soils can be an overwhelming challenge. Amending soils to correct problems is much easier before planting.

    Propagation

    Tree fruits do not come true from seeds and are difficult or impossible to reproduce from cuttings. The most common technique for fruit tree propagation is using budding or grafting techniques. Commercial nurseries use T-budding for apple and pear propagation and patch grafts for stone fruits. For hobbyists and novices, bench grafting is usually the most successful. All of these approaches join two plants. The upper part of the graft (the scion) becomes the top of the plant or the variety of fruit tree. The lower portion (the rootstock) becomes the root system. By grafting, we get the desired qualities of the rootstock (disease resistance, adaptable to certain soil characteristics, tree size) and the scion (fruit cultivar, such as ‘Fuji’ or ‘Golden Delicious’).

    Bench grafting. Scion wood (1-year-old shoots) should be collected in late winter, with care taken to select shoots that are approximately the same diameter as the rootstock. Matching cuts are made to both the top of the rootstock and the bottom of the scion wood. There are grafting tools commercially available that assist the beginning grafter in consistently making these matching cuts (see figure below). The appropriately cut scion and rootstock are combined and held together tightly with grafting bands so that the cambium (area immediately under the bark) of both pieces can heal and develop a union between the two plant parts. Late winter bench grafts will have time to heal and begin to develop a strong graft union before buds break and begin to grow in the spring.

    Rootstocks

    Tree fruit rootstocks are chosen based on a variety of criteria. Perhaps the most important is size control. Rootstocks primarily determine tree size. Apple rootstocks are available ranging from dwarf to full-size (standard or seedling). Some size-controlling rootstocks are available for pears and cherries. There are a number of rootstocks available for peaches, plums or apricots, but these do not show the same degree of size control as those for apples or cherries.

    Apple rootstocks in the Geneva series are designated with a G followed by a selection number (example – G.11, G.16, G.30). These were selected at the Cornell University research station in Geneva, New York, and are noted for resistance to fire blight. Although these aren't as widely available as the Malling rootstocks, the presence of fire blight in Utah would make Geneva rootstocks a good choice for the home garden.

    Planting

    Plant trees as quickly as possible after their arrival from a nursery into a well-prepared site. Dig a wide but shallow hole (about 24” wide by 12-15” deep). Place the tree in the hole and check to see if the roots spread out into the hole without hitting the edges or curling. Cut off any damaged or broken roots and any roots that are excessively long (12+ inches). Place the tree in the hole and backfill with the original soil. Press the soil firmly around the roots and water immediately. For trees on size-controlling (dwarfing) rootstocks, be sure the graft union is 3 to 4 inches above the final soil line. If soil is placed around the scion, the scion will root and the dwarfing influence of the rootstock will be lost.

    If trees are well branched (3 to 4 branches evenly spaced around the tree and at a good height) keep the branches. If there are no branches or if the branches are all on one side, cut the tree to about 36 inches and remove any side branches. New side branches will begin to grow from buds below the heading cut.

    Plant trees as quickly as possible after their arrival from a nursery into a well-prepared site. Dig a wide but shallow hole (about 24” wide by 12-15” deep). Place the tree in the hole and backfill with the original soil. Press the soil firmly around the roots and water immediately. For trees on size-controlling (dwarfing) rootstocks, be sure the graft union is 3 to 4 inches above the final soil line. If soil is placed around the scion, the scion will root and the dwarfing influence of the rootstock will be lost. Before planting, make a few vertical cuts through the sides of the root ball before setting in the hole. This will cut through any roots that are circling in the pot.

    Spacing

    The amount of space required for individual trees will vary based on the variety, the rootstock and the soil. Allow ample room so that trees do not shade one another. Tree Radius of space Standard apple 15-20’ Semi-dwarf apple 12-15’ Dwarf apple 6-10’ Pears 12-18’ Apricot 10-15’ Peach 8-12’ Plums 10-12’ Sweet cherry 15-18’ Tart cherry 10-12'

    Fertilizer

    Fruit trees, like all plants, need 13 mineral elements plus water, sunlight and oxygen to grow and thrive. If the site was well prepared, most of the required nutrients will be readily available in the soil. Since fruit trees are perennial plants, not all nutrients must come from the soil each year. Much of the nutrients that are taken up one year are available in subsequent years for growth and metabolism. The most common nutrient deficiencies on fruit trees in Utah’s home orchards come from a lack of nitrogen, iron, or zinc.

    Nitrogen deficiency is often characterized by small leaves with a light green color. The pale color is evident first in older leaves. Another symptom is a lack of adequate growth of new shoots.

    The actual amount of supplemental Nitrogen needed depends on the amount of organic matter in the soil, and the soil texture and nutrient holding capacity. A beginning point for nitrogen application is 1 ounce of actual Nitrogen per year of tree age, not to exceed 8 oz of Nitrogen per tree per year. Requirements may be higher for sandy soils and less for loam or clay soils. The actual amount to apply is based on the nitrogen concentration of the fertilizer. For example, ammonium sulfate is about 20% nitrogen. To apply 1 oz of nitrogen, you would need to apply 5 oz of ammonium sulfate fertilizer.

    The best gauge for nitrogen fertilizer application is the amount of tree growth. If new growth is excessive, reduce Nitrogen application.

    table with data

    Deficiencies of mineral nutrients, particularly micronutrients are diagnosed through tissue analysis. Collect leaves from the midpart of current season growth and submit to a testing lab for analysis. Your local county Extension office can help with this.

    Fruit trees, like all plants, need 13 mineral elements plus water, sunlight and oxygen to grow and thrive. If the site was well prepared, most of the required nutrients will be readily available in the soil. Since fruit trees are perennial plants, not all nutrients must come from the soil each year. Much of the nutrients that are taken up one year are available in subsequent years for growth and metabolism. The most common nutrient deficiencies on fruit trees in Utah’s home orchards come from a lack of nitrogen, iron, or zinc.

    Iron deficiency will also show up as a light green color on young leaves. As conditions worsen, the area between the veins becomes yellow or white (interveinal chlorosis). Utah soils actually contain large amounts of iron, but at higher soil pH, the iron is not available to the plant. Over-irrigation in the spring can make iron deficiencies more severe.

    Zinc deficiency is most easily identified by small leaves (little leaf symptom) which come out in a rosette. On previous years growth, there may also be a portion of the shoot that has no leaves immediately in front of the rosette.

    Minor element deficiencies are less likely in soils with sufficient organic matter content. Therefore, adequate site preparation will reduce the likelihood of subsequent problems. When iron or zinc deficiencies develop, the best remedy is to apply supplemental iron or zinc in “chelate” products. Chelates keep the iron or zinc fertilizers in a form that can be utilized by the plant. They work best when applied to the soil within the drip line of the tree, just prior to the growing season. This will likely have to be repeated each season. See the USU Extension Publication “Iron Chlorosis in Berries” for more information.

    Irrigation

    It is important to be careful that young trees do not dry out, especially during the first growing season. This is a critical time when the root system is being rebuilt from the shock of transplanting. However, homeowners often love their young trees to death by overwatering. During cool spring conditions, water loss will be minimal, but as the hot, dry summer conditions come, water loss both from the soil surface and through the young trees will increase. Water thoroughly once per week, gradually decreasing irrigation frequency as the tree becomes established. In hotter climates, young trees may need to be watered twice per week.

    The roots of established fruit trees are typically in the top 2 to 3 feet of soil, and these trees prefer deeper, less frequent watering than a vegetable garden or turf grass. The frequency and quantity of watering will depend on soil type and on weather conditions. For more specifics on orchard tree irrigation, see the series of Orchard Irrigation fact sheets available from USU Extension.

    Flowering and Fruit Set

    The biological process of producing fruit is a true perennial cycle. Flower buds begin to form in the spring and summer, continuing their development through the fall, and then open the following spring to produce the flowers and fruit. Therefore, fruit is developing in the current season at the same time as flower buds are forming for the following harvest. This means that management of the tree affects both this year’s and next year’s crops.

    Fruit set


    Fruit set refers to the process where a flower makes the transition to a developing fruit. Fruit set in tree fruits requires compatible pollen, an agent to transfer pollen (usually bees), pollen germination and growth of the germ tube through the style, and fertilization of the egg and formation of endosperm from both parents.

    Some tree fruits are self-fruitful (own pollen can fertilize the egg) and others require cross pollination (pollen from a different variety). The requirements are shown in Table 2 (next page). If one cultivar is to provide pollen for another, their period of bloom should overlap, particularly early bloom. Triploid apples such as Gravenstein, Winesap, Mutsu and Jonagold do not produce viable pollen, and cannot be used as a pollinizer. Also, some cultivars have multiple strains such as Cortland and Redcort, or McIntosh and Redmax. Since these apples are almost identical genetically, they will not pollinate each other. Ornamental crabapples and pears are also viable pollen sources. Nursery catalogs often suggest pollinator matches for cultivars that have specific cross-pollination requirements. For more information on cross-pollination see the University of Missouri fact sheet “Pollinating Fruit Crops”. Crop Cross-pollination Apple Require cross-pollination Pear Anjou and Bartlett are partially self fruitful. Cross-pollination will improve cropping Apricot Most are self fruitful. Perfection, Riland and Rival require cross pollination. Peach, Nectarine Most are self fruitful. J.H. Hale is not. Plums Some prune types such as Stanley and Damson are self fruitful. Most others either require or do better with cross-pollination. European varieties require other European varieties as cross- pollinizers. Likewise, Japanese plums need pollen from a different Japanese variety. Tart cherry Common varieties, such as Montmorency are self fruitful. Sweet cherry Stella and Lapins are self fruitful. Bing, Lambert and Royal Ann require cross- pollination

    Fruit trees almost always produce more flowers than needed for a full crop. Some flowers do not get pollinated and drop. Some flowers are pollinated and fertilized but the seed(s) fail to develop. In apples and pears, fruits that have more seeds are more likely to persist to maturity, while those with fewer seeds tend to drop from the tree in late spring and summer. Even with this fruit drop, trees tend to produce more fruit than can be adequately ripened. When trees carry too many fruit, the fruit tend to be small, and lack desired sugar, color and flavor. You have a choice, lots of little fruit of low quality or fewer larger, higher quality fruit. Adjusting the crop load to the appropriate level requires thinning. chart on thinning

    Diagrams of fruiting wood for apples and peaches.

    Flowers on apple trees are produced on short lateral shoots called spurs. Fruiting spurs can produce for multiple years, but produce the best fruit in the second and third year. Peaches and nectarines fruit only on 1-year-old wood. Cherries fruit on side shoots of both 1- and 2-year-old wood, with most of the production on 2-year-old wood.

    Fruiting wood formation on sweet and tart cherry (from Westwood, 1993)

    Thinning

    In the case of apples and pears, allowing the tree to carry too many fruit has the added side effect of reducing the crop for the following year. When trees produce a large crop one year, there is often a very small crop or no crop the following year. Seeds developing in the fruit produce plant hormones that prevent the nearby development of flower buds. Large crops also deplete the tree’s carbohydrate reserves which can further interfere with flower bud development, and in some cases can reduce the cold hardiness of the buds and shoots, increasing susceptibility to winter injury.

    Thinning apples and pears maximizes fruit size and quality, and ensures return bloom the following spring. Timing of thinning is very important. Optimum timing is usually in the first 2 to 3 weeks after bloom. Later thinning has less effect on fruit size, and will not improve flower bud development for the following year, resulting in “biennial” or “alternate” bearing. The basic concept of apple thinning is to remove all of the fruit from at least half of the fruiting spurs, so that these non-fruiting spurs can produce flowers for the following season. In practice, leaving one fruit for every three spurs is ideal for both fruit size and return bloom.

    Peaches, nectarines and apricots need to be thinned to improve fruit size and quality, but typically produce more than adequate bloom with or without thinning. A combination of inadequate or improper pruning and lack of thinning can result in limbs breaking off due to crop load, a common problem in home fruit trees. As mentioned above, peaches fruit on 1-year-old shoots. For ideal fruit size, limit the number of developing fruit to 1 to 2 fruits per shoot, and space fruiting shoots during dormant pruning. Cherries and plums are typically not thinned, but fruit crop also can be reduced during dormant pruning by removing more of the fruiting wood.

    In colder parts of the state, the most common limiting factor in home fruit production is cold damage to developing flower buds resulting from spring frosts. Selecting the proper site and variety is the first line of defense against spring frost damage.

    When cold temperatures come during critical stages of bud development, raising the temperature around the bud only a few degrees can be the difference between having fruit and just having a shade tree. Dwarf or young trees can be protected by tarping the tree. Cover the tree with a canvas or poly tarp and tie or anchor the edges to prevent the tarp from blowing away. Flowers and buds that are in contact with the tarp will still be damaged, but the tarp will hold warmer air in the tree and keep the remaining buds warmer. To provide additional heat, a 60-watt light bulb may be suspended in the canopy center and left on through the night. Other simple heat sources include a small propane burner or burning charcoal briquettes. Remember, however, that the tree doesn’t need to be warm, just kept above the critical bud temperature for the particular stage of development. Promptly remove the tarp in the morning once the air temperature exceeds 32 F. Remember that too much heat will speed bud development, creating more challenges on the next cold night.

    Training and Prunning

    Training is to cause the branches to grow in a particular direction or fashion. The primary object of training and pruning fruit trees is to manage light. Shading of one leaf by another reduces light interception of the shaded leaf by 90% and thus reduces photosynthesis by 28%. About 30% of full sunlight is required to achieve the maximum rate of photosynthesis. In gardens, a secondary reason to train and prune trees is to improve aesthetics.

    Limb orientation is an important factor in productivity. Branches that are growing mostly upward are vegetatively vigorous, but not fruitful. Branches that are growing mostly horizontal are very fruitful, but have too little vegetative vigor. The ideal branch angle is about 30° to 45° above horizontal. This allows for vegetative growth while providing as much fruitfulness as possible. It creates a balance between growth and fruiting. Careful bending of young branches, and holding these branches horizontally with string or weights, will help bring young trees into production.

    Many different approaches have been used to train or position limbs. Spreading involves using wooden sticks or metal rods to push branches downward. Tying involves using string or twine to pull branches downward. The twine can be connected to a stout stake or to a nail or screw in the base of the tree stake. Weighting involves fastening small weights on branches to pull them downward. Filling small paper cups with concrete makes a simple weight. Put a J-shaped piece of wire in the cup while the cement is wet to form a hook for hanging the weight in the tree. Trellising can also be used for limb positioning. Many different types of trellises can be used for fruit trees. Some are very elaborate such as espalier. Others simply consist of two to three horizontal wires connected to strong posts. Limbs are attached to the wires to hold them in the desired position. Trellises can also help support a growing crop. Trellis systems don’t work very well for stone fruits.

    Pruning definitions

    Types of wood:


    Suckers are vigorous shoots that arise from the roots or the rootstock shank below the graft union. Watersprouts are vigorous upright shoots inside the canopy, often originating near a pruning cut. Spurs are short lateral shoots (approximate length of 4 to 6 inches) that are the primary site of flowers and fruit for most modern apple varieties. Leader is the main vertical axis of the tree. Scaffolds are major lateral branches.

    Types of pruning cuts:


    Heading cut is removing part of a branch, but not the entire branch. Thinning cut is removing a branch to its point of origin. Stubbing cut is a heading cut into 2-year-old or older wood. Bench cut removes a vigorous upright branch back to a horizontal side branch. This should be avoided as it creates a proliferation of vigorous shoots just below the cut.

    Dutch cut is removing a branch except leaving a short stub on the main leader. Often, a new branch will arise from this short stub to replace the branch that was removed. This is often the approach used to replace a damaged or broken limb.

    Growth Response to Pruning


    Trees respond differently to different pruning cuts. Heading cuts into 1-year-old growth will produce strong growth of several branches just below the cut. Further, when more wood is removed (a lower cut), the regrowth is more vigorous. Where a single branch grew before a heading cut, several strong branches will grow the following year. Usually this is not desirable. Thinning cuts, where the entire branch is removed, produce less regrowth and are preferred. Stubbing cuts into older wood usually produce less regrowth than a heading cut into older wood. Where large cuts are made in the canopy interior, particularly on old trees, significant regrowth occurs. This growth is usually as water sprouts. Making large cuts usually results in a “cut and grow” cycle that is hard to escape. This cut and grow cycle becomes even more problematic when excessive nitrogen fertilizer has been applied. Where heavy pruning is required, avoid applying fertilizer Nitrogen.

    Pruning procedure


    Sometimes it is difficult to know where to begin to prune fruit trees. Some cuts are more important to make than others. The following protocol is suggested for pruning. Pruning steps by order of priority are to (1) remove problems, (2) establish and maintain tree shape, (3) space wood to allow for adequate light penetration.

    Problems to address include removing diseased, broken or damaged branches, branches that are crossing or rubbing, or form a narrow angle from the main scaffold. Old branches with long complex spurs should also be removed to make room for younger more productive branches.

    Tree shape should be maintained through selective thinning cuts. Pay attention to branch orientation, remembering the “45-degree rule.” Branches that are too upright will remain vegetative, while pendant branches (below horizontal) are typically shaded and too weak to be very productive.

    Branch density is the final objective. Frequently evaluate branch density during pruning. Periodically take a step or two back to see what the tree shape looks like. Are dense masses of limbs present? Can light penetrate into the tree interior? Could you conceivably throw a baseball cap through the tree without it hitting a branch? You should be able to see through the tree when leaves are not present. Don’t just look through the tree from side to side. Also, look upward through the canopy. You should be able to see through the canopy this way as well.

    Use only tools that are made for pruning trees. These include loppers, hand shears, pruning saws and an orchard ladder. Orchard ladders have three legs and are more stable on uneven ground than standard home ladders. Keep cutting tools sharp and in good repair. Clean hand shears and loppers with a light oil and a scratch pad before storing. This also keeps tools from rusting. Sharpen the cutting blade with a small sharpening stone. Be sure to use pruning tools only for pruning. Pruning tools may be a means of spreading disease inoculum. Therefore, disinfect tools between cuts when removing branches you believe may be diseased. Use a 10% bleach solution and soak the pruning implement between each cut for at least 10 seconds. A practical way to do this is to use two pruning tools, soaking one while the other is being used, then swap tools. Rinse thoroughly after use and cover with a light oil to reduce corrosion.

    The best time to do most pruning is in the early spring when the trees are still dormant. Normally this time runs from February to late April. Do not prune fruit trees during the fall. Pruning invigorates the wood around the pruning cut which can delay or prevent the tissue from acclimating for winter conditions. Trees that have been pruned in the fall may not harden off properly and will be less able to withstand cold than trees that have not been pruned. Summer pruning apples in late July to early August to increase light- reaching fruit is acceptable.

    This is a very difficult task to do. Trees that have been neglected will have dense masses of limbs on the tree interior. These need to be thinned out to allow light and air through the canopy. As these cuts are made, additional growth is stimulated that will have to be removed the following year that, in turn, will stimulate more growth. Typically, renovating old trees requires 3 or 4 years of intensive pruning. Older trees are frequently on seedling rootstocks and occupy substantial space. Limbs may be rotting on the inside and the tree may not be structurally sound. It is recommended to replant rather than reclaim. You can order a new tree on a dwarfing rootstock that will take up less space. You will also be certain about what kind of tree you have — and you can expect many years of good quality fruit from the tree.

    Common Pests and Diseases

    Click on fact sheets. for bulletins on individual pests, or for the Utah Home Orchard Pest Management Guide, which lists specific recommendations and general information on when to treat (all found in the “insects – tree fruit” category).

    For more specific and up-to-date information on tree fruit pest activity and treatment recommendations, consider subscribing to the Tree Fruit IPM Pest Advisory, a semi-weekly newsletter that is sent via email. Go to utah pests for information on signing up.

    Fruit Maturity and Storage

    A number of factors will help you determine if fruit is sufficiently ripe for harvest. Keep in mind that “tree ripe” fruit is great to eat but will not keep long and the quality will diminish quickly. If you intend to store fruit for a time through freezing or “home canning,” you should consider harvesting it at the firm ripe stage rather than tree ripe.

    One of the best places to start when determining fruit ripening is to know the characteristics of the particular variety you have. Nurseries can generally provide you a list of fruit trees in order of ripening. When selecting trees for a home orchard, this list can help you choose the varieties that will best meet your needs. For example if your desire is to have enough fruit to home can then you should choose varieties that ripen at about the same time. If you desire is to have a smaller amount of fruit throughout the season then choose several varieties that ripen at different times.

    Stone Fruits

    Fruits that contain a pit such as peaches, apricots, and nectarines go through a “final swell” the last 2 weeks prior to harvest. During this time fruit size increases rapidly, the flesh begins to soften and the fruit becomes sweeter. The outside skin color also changes, turning from green to more red and yellow. The shaded side of the fruit (facing the ground or to the inside of the tree) will also begin to turn from pale to more of a cream or yellow color.

    Pome Fruits

    Apples and pears will also change in their appearance as they begin to ripen. Apples in particular will take on their “fall color” and the red and yellow pigments will become more noticeable. Internal seed color will begin to turn dark and the fruit will begin to soften.

    European pears will not ripen while on the tree, and should be harvested and stored for several days to complete ripening. As pear fruit approaches ripeness, the small pores on the fruit surface (lenticels) will turn from white to brown, the peel color becomes lighter colored, and the fruit will begin to loosen at the stem during the final stages of ripening. Asian pears stay firm when ripe and will ripen similar to apples.

    Apple and pear fruit should come loose from the branch with a gentle lift and twist. Picking the fruit by pulling down will break the fruiting spur. Many homeowners have the mistaken notion that winter apples aren’t properly ripe until they have been frozen. The conditions that result in ripening are cold nights (not freezing) and sunny days. Ripe apples will freeze when the fruit temperature is about 28 F. Once frozen and then thawed, apple tissue will begin to break down rapidly. If fruit freezes on the tree before you can pick it, it may not be a total loss. Wait until the fruit thaw on the tree, then pick and eat or process (juice or sauce) as quickly as possible.

    To maximize the post-harvest life and quality, ripe fruit should be harvested when temperatures are cool, or the fruit is cooled as soon as possible after harvest.