Starting a Home Fruit Garden

All fruit plants need a period of cold weather once they become dormant in the fall. The amount of cold that overwintering buds need in order to develop flowers and fruits properly for the following year is referred to as the chilling requirement. The accumulation of chilling hours affects the fruit plant’s balance of growth hormones.  It is often measured as the cumulative number of hours between 32 and 45 degrees Fahrenheit beginning with the first fall frost. The production of growth-promoting hormones increases and the production of growth-inhibiting hormones decreases as the plant comes closer to meeting its chilling requirement.  

In Maryland, chill hours range from 950 in Western Maryland to 1,300+ on the Lower Eastern Shore. The number of chill hours will vary yearly based on weather conditions. There are enough chilling hours in Maryland to grow all of the recommended fruits on this website. 

Most fruit nurseries list the chill hour requirements of the varieties they sell. “Low-chill” varieties require less than 300 chill hours. This table shows the broad range of chilling hour requirements for common fruit plants. Varieties bred for far Southern or Northern regions may have requirements outside these ranges.

 Chilling hours are more of a concern for gardeners in very warm and very cold regions of the U.S. For Maryland gardeners, the plant’s hardiness, bloom time, and extreme weather events are more important considerations than chill hours. For example, fig plants may need protection from extreme cold temperatures to avoid injury to main stems. Chilling hours might be a concern if you grow a very low-chill variety that comes out of dormancy during a late winter warm spell and is then injured by a late freeze. Chilling hours directly affect fruit bud development, but the rate of overall plant growth in spring is determined by weather, soil conditions, and fruit species and variety.

Mid-Atlantic weather is becoming warmer, wetter, and more extreme. Warmer weather in winter and early spring can stimulate early emergence from dormancy, making flowers and young fruits vulnerable to late frosts and freezes. Higher winter temperatures overall can reduce winter injury to cold-sensitive plants like fig and pomegranate. Even with a warming climate, we will have periods of very cold winter weather that can injure plant roots, crowns, bark, and buds. The level of injury depends on the type and variety of fruit, and the timing, duration, and severity of the cold weather. High summer temperatures and droughts can stress and injure plants and fruits (e.g., sunscald).

Resources:

• University of Georgia (with national chill hours map)
• University of Arkansas
• University of Alabama
• Penn State University

• Pollination involves the transfer of pollen from the anthers (male parts) to the stigmas (female parts) of flowers. 
• Depending on the type of fruit, the pollen transfer may occur: from the anthers to the stigmas of the same flower; to stigmas of different flowers on the same plant; or to the stigmas of flowers on different plants. 
• Pollen grains fertilize the ovules (undeveloped seeds) that reside in the ovary (undeveloped fruit). The pollination/fertilization process causes fruits to grow and ripen. 
• If the flower is not fully pollinated, the fruit may fall off prematurely or be malformed. 
• Consult fruit catalogs, websites, and reference books for pollination and bloom time information for specific cultivars. Enough overlap in bloom time needs to occur for cultivars to be compatible for pollinating each other.
• For the majority of fruit plants, pollinators are essential for best fruit production, so it is very important to support these insects. Bees are key daytime pollinators, and moths may be equally important at night. Never spray insecticides on blooming fruit trees or when pollinators are present. Limit overall pesticide use, and select least-toxic products when pest management is needed.
  • Native bees (pollen bees)- bumble bees, carpenter bees, orchard/mason bees, and many other bee types are responsible for more than half of all fruit plant pollination, and can be more effective at pollination than European honey bees. There are over 4,000 North American native bee species, and many are threatened by habitat loss, parasites, predators, and infections, and pesticides.

Self-fruitful crops do not need to receive pollen from another plant from cross-pollination; growing a single plant can yield fruit. They include: peach, nectarine, apricot, grape, raspberry, blackberry, strawberry, tart cherry, currant, gooseberry, jostaberry, and fig. Many European and Japanese plum cultivars are self-fruitful, though not all. Blueberries and elderberries fruit best with cross-pollination, but can produce a smaller harvest without it. When plants produce fruits without pollination, the fruits will be seedless. 

Self-unfruitful crops require pollen from another plant of the same type in order to fertilize the flower to develop fruit. At least two different individual plants of the same species are needed. You can use either two distinct wild-type plants (seed-grown or cuttings from different individuals), one wild-type and one cultivar, or two different cultivars in order to have enough genetic differences for compatible pollen. For example, a European pear cultivar won’t be a suitable pollinator for an Asian pear cultivar; you need a second European pear. Similarly, two ‘Fuji’ apples cannot pollinate each other because they are genetically identical and bear the same pollen, being the same cultivar. ‘Gala’ and ‘Fuji’ are genetically different and can cross-pollinate so each tree produces fruits.

Self-unfruitful crops include most varieties of apples, pears (Asian and European), and sweet cherries. Ornamental fruit trees (varieties grown only for flowers) may provide needed pollen for a good fruit set if they are within 100 feet and if their bloom period overlaps with the fruit trees. For example, crabapple trees are excellent pollinators for fruiting apples. Blueberries will yield larger fruit and a bigger harvest if two different cultivars can cross-pollinate. Pawpaw is often seed-grown and will require cross-pollination; cultivars will need pollination from either a wild-type tree or a different cultivar.

• Identify suitable locations in your yard (or community garden if permitted) in the fall. 
• Don’t crowd plants! Take into account the expected mature size of the desired fruit plants to make sure that you have enough room, especially if another cultivar is needed for cross-pollination. 
• Select a location receiving full sun, which is at least eight hours of direct summer sun. Blueberry, currant, and gooseberry will grow well in six hours of direct sun. Pawpaw will tolerate more shade, though the harvest can diminish. Leaves and fruits dry faster in full sun, reducing the risk of infection after rain, dew, or irrigation. Fruit will also color-up better and ripen more evenly. Northern exposures shaded by trees or buildings usually don’t receive enough direct sunlight for growing fruit.
• Lawn grasses and weeds will compete with your fruit plants for water, sunlight, and soil nutrients. Before planting, kill existing vegetation by covering it with a tarp, landscape fabric, or cardboard. These covering materials should be removed once the vegetation is completely killed.
• The soil should be well-drained, where water doesn’t pool and remain on top of the ground after heavy rainfall. Stone fruits, particularly peaches, do not tolerate “wet feet” (having roots in poorly-drained, compacted clay soil). Very sandy soils drain quickly and require more frequent irrigation. Pears are somewhat tolerant of heavy clay soils, as are pawpaw, elderberry, and chokeberry. Small fruit species tend to have shallow, fibrous root systems and grow best in well-drained soil high in organic matter (at least 5% in soil test results).
• Planting in raised beds can improve root aeration when the underlying soil is high in clay and drains slowly.
• Fruit plants need adequate soil nutrients for good growth and productivity. If planting in spring, test the soil in the fall so that you can change the soil pH and correct nutrient deficiencies if needed. This is very important when planting blueberries because the soil pH may need to be lowered with sulfur. All other fruit plants will grow well in a 6.0 to 7.0 soil pH range. 
• Increase the organic matter content of the soil before planting. Organic matter enhances root growth, provides a wide range of nutrients, and increases the soil's water-holding capacity. 

Resource: Home Orchard Site Selection (Penn State University)

Fruit trees for sale are not grown from seed, with the exception of a few native species like pawpaw. They are propagated vegetatively, as rooted or grafted cuttings, from plant tissue taken from a known variety. Tree fruits, especially apple and pear, are genetically complex. If grown from seed, they will not be true to the variety -- the offspring trees and their fruits will have different traits from those of the parent tree. (Peach can be an exception.) Most temperate fruit tree seeds also need special treatment, such as exposure to winter conditions, to germinate reliably.

• Fruit plants should not be an "impulse purchase," even though trees may look tempting in a store or catalog. Avoid multi-fruit trees like the “5-in-1” apple (five cultivars combined into one tree), because they are harder to grow successfully
• Bargain plants may not be healthy or may be a variety not well-adapted to your area.  Buy recommended varieties from local nurseries and garden centers or from specialized fruit nurseries, preferably located in the mid-Atlantic.
• When purchasing from a mail-order nursery, place your order December through February for spring planting, specifying the cultivar, size, grade of plants desired, and preferred time of shipment. It is best to have the plants arrive when you are ready to install them. Have the planting site prepared well in advance of planting.
• Bare-root plants will catch up to container-grown plants and are less expensive. 
• Be sure that you understand your suppliers' terms, return policy, and guarantees.
• When possible, select varieties that have resistance to diseases you are likely to encounter. 
• Consult fruit cross-pollination charts in nursery catalogs when making decisions about which cultivars are compatible.
• Grafting is the process of uniting two different plants, usually by merging a stem from one variety (called scion) with the roots of another (called rootstock), and it can provide several advantages. Most tree fruits are grafted onto rootstock that is hardier and more pest- or disease-resistant than the root system of the desired cultivar would be. Rootstocks may also dwarf the tree, making it easier to manage. 
• A preferred starting size for fruit trees is a healthy one-year-old “whip,” approximately four to six feet tall with a good root system.
• Tissue culture is the process of propagating a plant cultivar by multiplying tissue samples in a lab. This results in highly uniform, free of diseases. Strawberry, raspberry, and blackberry plants are the fruits most often designated and sold by fruit nurseries as propagated by tissue culture. Tissue-cultured plants are grown in a greenhouse and are more cold-sensitive at first than plants propagated outdoors, so plant them only after the last frost date. 

• Suckers are new stems arising from the plant’s root system, often appearing some distance from the main cluster of stems or original trunk. Some fruits sucker more readily than others, such as raspberries, blackberries, pawpaw, and chokeberry. Small fruits are easy to propagate from cuttings and the root suckers of established plants, but it’s illegal to propagate commercial cultivars with a Plant Patent (PP) designation. Don’t propagate wild brambles because they may carry viruses; viral infections are incurable.

The best time to plant is late February through March, before buds open. The second-best time is mid-September through mid-October (except for stone fruits, which should only be planted in spring because they need more time to establish). The soil should be prepared before planting.

When bare-root or mail-ordered plants arrive:

• Check the label closely to make sure that you are getting the correct cultivar and (for fruit trees) rootstock.
• Unpack the bundles and inspect the plants. The roots should be moist and have a bright, fresh appearance. Shriveled roots indicate that the plants may have frozen or dried out in storage or transit and may not survive. Plant roots must be kept moist and free from freezing temperatures at all times.

• If the plants can not be set out immediately, wrap them loosely in a plastic bag with some holes cut for ventilation and store them at a temperature just above freezing.  Surrounding the tree roots with moistened sawdust, shredded newspaper, or peat moss will prevent them from drying out.  Strawberry plants, in small quantities, may be held in a refrigerator for a few days. Pack the soil firmly around the roots to eliminate all air pockets and to prevent the roots from drying out.
• You can plant your small fruit plants and fruit trees in a temporary trench of moist soil in a shaded location, a technique known as “heeling-in.” The root system is placed in the trench with the trunk or stems nearly parallel to the ground. Firm soil around the roots to eliminate air pockets and prevent root drying.
• Hydrate the root system of fruit trees for 4-6 hours the day before planting by placing them in a large container filled with water.
• Before planting, use sharp pruners to trim any roots that are broken, or damaged, or badly kinked (sharply elbowed).

• Plant fruit trees so that the graft union (the bulge where rootstock meets scion wood on the trunk) is two to four inches above the ground after the soil settles. The root flare should sit just at the soil surface.
• If your fruit plants are container-grown and they are pot-bound (circling, overgrown root system), gently tease the roots apart and trim excessively long roots to encourage root expansion into the potting media. You may need to score the sides of the root ball with a sharp knife to loosen the roots. 
• Plant small fruit plants so that the roots are covered and the crown (where stems emerge from the roots) is 1-2 inches above the soil.
• The diameter of the planting hole is more important than the depth of the hole. The hole should be big enough to lay the roots out without crossing or bending them, although very long roots can be pruned. 
• Backfill the hole, firmly packing the soil around the root system, and water well.

• Add a complete liquid fertilizer (contains nitrogen, phosphorus, and potassium) to the water applied around the roots after planting. Follow the dosage recommendations on the product label.
• You can build a low ridge of soil one to two feet from the tree base to hold water in.
• Place a three-inch layer of organic (biodegradable) mulch under the tree, starting at the tree’s drip line (branch spread) and tapering to zero inches at the trunk. Apply mulch around small fruit plants, similarly keeping the crown uncovered to maintain good air circulation.
• Water deeply throughout the first year, as needed to supplement rainfall.
• Ripening fruit is a significant resource drain, and young plants should put this energy into root establishment and sturdier branch growth instead.
  • Do not allow fruit trees to bear fruit before their third season after planting. Remove the flowers and fruits from small fruit plants the first year after planting. 
  • Remove flowers from strawberry and bramble plants for one year after planting. 
  • Remove flower buds (or open flowers) from blueberry plants for two years after planting. If plants are vigorous, you can leave half of the flower buds in the second year and allow them to produce fruit.

Fruit Plant Care 

• Many fruit plants will grow in a container, but will not be as large or productive as the same plant growing in the ground. One advantage of using containers is portability, especially for citrus and other tropical and subtropical plants that will be moved indoors or into a greenhouse at the end of the growing season.
• Containers restrict root growth for tree fruits and small fruits. When roots run out of growing space, the plant’s ability to grow is limited, which reduces flowering and fruiting. Some of the common causes of failure are undersized containers, insufficient sunlight, and insufficient or inconsistent watering. Larger container volumes will encourage larger root systems and won’t dry out as quickly, but they are also substantially heavier, making them more difficult to move.
• There are cultivars bred for container use for raspberry, blackberry, and blueberry, as well as columnar apple trees, which are slender single-stem plants 8-10 feet tall that can more easily fit into tight spaces. 
• Recommended minimum container sizes:
  • 16” diameter (10 gallon capacity) for raspberry and blackberry
  • 18” diameter (15 gallon capacity) for blueberry, currant, gooseberry, and fig
  • 21” diameter (20 gallon capacity) for small fruit trees like columnar apples and dwarf peaches
• If containers are placed on hard surfaces, place them on top of bricks for drainage. 
• Fill pots with a 50:50 mix of compost and lightweight soilless potting mix. Moisten the potting mix before filling containers.
• Keep root systems moist at all times. Drip irrigation systems with one or more emitters per container can be used to water plants with a battery-operated faucet timer.
• Fertilize regularly through the growing season, starting in spring when leaves start to expand. Use a complete and balanced all-purpose fertilizer that contains macronutrients (nitrogen, phosphorus, and potassium in roughly equal amounts) as well as micronutrients like iron and manganese. Foliage should have a deep green color. Overfertilizing with nitrogen will result in soft, succulent growth and reduced flowering and fruiting.
• Move containers to protected locations over the winter, and mound bags of leaves, mulch, or straw bales around the sides of the containers to reduce the risk of winter injury to root systems. Do not move cold-hardy plants indoors, because it will interfere with dormancy.

Placing bags of leaves or straw around the containers will help protect the root systems from cold injury. Also, water the plants periodically during the winter if rainfall is lacking to prevent root desiccation. Larger containers (up to 50 gallons) are less likely to suffer severe root injury because they do not change temperature as drastically.