Long summer days, cool nights, and a mostly dry season are ideal conditions for growing fruit trees. Fruit trees require freezing or close to freezing temperatures during the winter, but generally need at least 150 days between the last spring frost and the first fall frost so that blossoms are not damaged in spring and so that the fruit will mature in the fall.
Do not plant in low spots or areas that flood frequently. If you are planting on a site where the soil is shallow because of a hardpan, break through the hardpan when preparing for planting. Do not plant trees too close together, as this may cause poor growth.
Most fruit trees do best in areas with full sun, good air movement, and well-drained soils at least 4 feet deep. Apples and pears do best in soils at least 6 feet deep. Plant in unshaded areas as much as possible to prevent diseases. The best soils are fertile, slightly acidic sandy loam soils free of alkali or salinity. Avoid sandy, high clay, or shallow soils, although pears can tolerate clay or wet soils better than other fruit trees can. Cherries, peaches, and nectarines cannot tolerate soils without drainage whether from hardpans, claypans, or saturated soil conditions.
Chilling hours are defined as the number of hours that the temperature is below 45° F. It is important to make sure that your area has adequate chilling hours because inadequate chilling will result in delayed foliation and uneven fruit development.
Apples are best adapted to areas with adequate chilling hours for most varieties--1,200 to 1,500 hours below 45° F to fully satisfy the chilling requirement. However, some varieties will produce with less. In areas with a maritime climate, choose low-chill varieties.
Pears are best adapted to areas with adequate chilling hours for most varieties--600 to 800 hours below 45° F to fully satisfy the chilling requirement.
Apricots are best adapted to areas with adequate chilling, which for apricots is 600 to 900 hours below 45° F. There are a few low-chill varieties that will bear with only 350 hours. Because of the early blooming habit of apricots, avoid planting where late spring frost occurs to avoid light crops. High temperatures also influence the quality of fruit. In areas of high rainfall, apricots do not regularly set fruit and are subject to many diseases.
Cherries have a fairly narrow range of adaptability, however they are very popular home-grown trees and can be found in most growing areas in California. For optimum production they require moderate summer temperatures because in high summer temperature areas, the fruit tend to double or spur. Cherries will not be productive in foggy coastal areas because of disease problems. Cherries require between 800 and 1,200 chilling hours. They bloom late so tend to be less injured by late frosts.
Peaches and nectarines are best adapted to areas with 600 chilling hours for low-chill varieties to 900 for higher chilling varieties. Late frosts can also damage newly developing flowers and fruit, as peaches and nectarines bloom early. Adequate heat is required in the summer to ripen fruit properly. Cool, wet climates are not typically good for growing high-quality peaches and nectarines.
For plums and prunes, there are low-chill varieties including the interspecific hybrids (crosses between apricots and plums) that will tolerate warmer conditions. Japanese plums require from 500 to 900 chilling hours and European plums require 700 to 1,000 chilling hours to satisfy the chilling requirement.