Chill hours are the total number of hours below 45°F and above 32°F during winter while the plant is dormant. Not all plants have a chill hour requirement, but for those that do, if they need more chill hours than your location provides, they may not bloom or set fruit.
Bloom Date and Late Frost
Some locations have late frosts after a warm period in the spring. These frosts can destroy the buds on early blooming plants and severely reduce fruit production. There is also a trade-off between bloom times and chill hours. Often, especially with fruit trees, late-blooming plants need longer chill hours. The average chill hours and last frost date for your location will help determine which plant variety is best.
Some fruit plants are self-fruitful (self-pollinating or self-fertile) and do not need pollen from another plant. Many, however, require a different cultivar as a source of pollen so each can pollinate the other. Still others simply do better with a second plant of the same type. A few cultivars do not produce pollen at all and are dependent upon another one that does. Still others will produce fruit on their own but the seeds will be sterile or missing without another pollen donor. Finally, some species have male and female flowers on separate plants. To sum up, you may need to purchase two plants rather than one unless you are sure that you have a plant that is self-fruitful.
Years Before Fruiting Another factor to consider when choosing a fruit-bearing plant is the number of years between planting and when the first fruit will appear. Generally, plants grown from seed can take the longest time to produce fruit; plants purchased in five-gallon containers, and plants grafted onto a special rootstock, will take less.
Tree Size and Longevity
It can be hard to get at the fruit at the top of a 25' full-sized tree that has not been pruned to control its height. Some ways to control the size of a fruit tree are to use (1) genetic dwarf trees which are smaller at maturity; (2) dwarfing rootstocks; and (3) large containers that limit the root volume and hence the total size of a tree. The disadvantage of dwarf varieties is that, for some species, they may have a shorter life span, or not be drought tolerant, compared to full-sized trees. Containers are not appropriate for all plants, may severely limit the health or performance of some, and will need more frequent watering.
Water Usage by Plant
Below are the gallons of water used to produce one pound of harvested fruit per plant. This is a United Nations estimated average for the world as a whole. Usage may be less in some regions. Tree crops consume more water than non-tree crops, and nut crops consume more water than wet fruit crops.
Read About Your Plant
It is important to have enough information about the plant you want to buy that you understand selection and cultivation issues thoroughly. Be familiar with your location's climate zone, chill hours, and soil. Choose the microclimate in your yard that is best for the plant. Understand what varieties will do best in your location. Know what fertilizer to use when and what soil acidity level is needed for each plant.
Do not plant fruit trees near other trees or large shrubs where their roots may compete. Keep a minimal distance between trees based on the maximum width of the larger tree when mature.
Fruit trees often require large holes that are at least 3' deep, at least twice the diameter of the pot they come in, that drain well, and that are filled with properly amended soil.
Young fruit plants do not compete well with weeds and need weeds removed under the canopy above the roots. Because many plants have shallow roots, hoeing can damage them if the hoe digs too deep. Pulling weeds by hand to avoid root damage is a safer option.
Watering Fruit Trees - Basin Irrigation
Double ring basin irrigation means (1) building a circular dirt dike one or two feet outside the drip line (tree canopy) surrounding the tree; (2) building a second dirt dike circle inside the first, one foot away from the trunk; and (3) flooding the area between the dikes with water, deep soaking the soil to a depth appropriate to the species of fruit tree. The inner dike avoids getting water on the graft union and causing disease. For all but a few plants, the soil should dry out at least 6" deep between waterings. Most fruit trees will need soaking in this manner once a week while they are fruiting.
Culling Excess Fruit
It takes many leaves to support one fruit, and larger fruit require more leaves. For most Prunus species, remove excess small green fruit so that those remaining are spaced 8" apart. This includes apricot, peach, nectarine, plum and pluot. Other species may also need green fruit culling to provide a proper leaf to fruit ratio. Culling keeps the total fruit load from breaking branches and avoids undersized fruit. Blueberries need short shoots pruned to remove excess berry buds so the remaining berries can grow larger.
Reasons to Use Containers
Strawberries and blueberries need moderate to high soil acidity and consistent moisture. Containers are an easy way to achieve this environment when local soil is alkaline and dry. One caution: do not use concrete containers. They are alkaline and inhospitable to acid-loving plants.
Companion and Antagonist Plants
Antagonist plants are those that should not be near the plant you are putting in the ground. They may take up the same nutrients as the desired plant, chemically interfere with its growth, or carry the same diseases. Companion plants are those that keep insects away with their scent or those that attract beneficial insects which prey on plant-destroying insects.
For example, do not plant blackberry vines where tomatoes, peppers, potatoes or eggplant have grown or are growing. Pear trees need to be far away from apple trees, roses, pyracantha and Bermuda grass. On the other hand, apple trees are helped if you plant chives, marigolds, nasturtiums and/or onions thickly around them as companions.
Food crops in Tucson, Phoenix and Southern California need to be protected from hungry rats, rabbits, birds, javelina, deer and more.
Gnaw guards should be installed around the base of many fruit trees, especially rose family members, to keep rabbits and rodents from eating the bark and possibly killing the tree. These are made of 1/4-1/2" wire mesh, wrapped around the trunk, but not tightly, with the bottom buried in the ground so a mouse, vole or rat cannot tunnel underneath. The guard must be adjusted periodically so the trunk can grow without getting constricted. Plastic pipe is also sometimes used. The guard should rise at least 10" high above ground.
Irrigated trees need to be in an area surrounded by a stout fence to keep out javelina that like to dig and lie in moist, shaded soil. Trees should also be draped in large bird nets, reaching to the ground, with no openings.
To keep rabbits out, grow berries in 18" high raised garden beds or use 18-24" high chicken wire. Young rabbits can get through 2" x 4" fencing.
Protecting from Frost Two methods can be used to protect a plant from frost. One is to pack it in hay bales while temperatures are at or below freezing. Second, with holiday lights hung on the tree, place a tarp over the top with the lights turned on. Remove the hay and tarp during the day if the plant is evergreen, unless wind chill remains below freezing.