The unique desert environment of Arizona creates a distinct and extended citrus season, making the timing of the orange harvest a careful balance of climate and variety. The significant temperature swings, with warm days and cool nights, directly influence the sugar development and acid content within the orange. This specific climate requires growers to rely less on visual cues and more on varietal harvest schedules and taste testing to ensure maximum sweetness and flavor.
Arizona’s General Citrus Season and Climate Factors
The broad window for harvesting oranges in Arizona typically begins in the late fall and extends into the spring, running from November through May. The distinct temperature profile of the desert drives the fruit’s quality and flavor. Cool nighttime temperatures are beneficial because they slow the fruit’s respiration rate, allowing sugars to accumulate. This diurnal temperature variation concentrates the sugars and reduces acidity, giving Arizona citrus its characteristic sweetness. The fruit’s exterior color change is primarily a response to these temperature drops, not a guarantee of internal ripeness.
Timing the Harvest for Popular Arizona Varieties
Arizona’s orange harvest is staggered across the winter and spring months, with different popular varieties maturing at specific times. Knowing the general timing for the type of orange planted is the first step in planning the harvest.
Navel Oranges
Navel oranges, known for their seedless flesh and easy-to-peel rind, are considered an early-to-mid-season fruit. The primary harvest window for most varieties, such as the ‘Washington’ Navel, starts in early December and lasts through February or March. Some early-producing navels may be ready as early as late October or November, often before they achieve full orange color. If left on the tree too long, Navel oranges can suffer from granulation, where the juice sacs dry out.
Sweet Oranges
Mid-season oranges, often marketed locally as “Arizona Sweets,” generally follow the Navels. Varieties like ‘Hamlin’ and ‘Pineapple’ are typically ready for harvest from November through February. These sweet oranges are highly valued for their abundant juice content and can hold their quality on the tree until February.
Valencia Oranges
Valencia oranges are the latest-maturing variety and significantly extend the Arizona citrus season. They are ready to pick starting in late winter or early spring, with the best quality fruit available from March through May. Valencia oranges hold well on the tree for several months after maturity, often becoming sweeter over time. They are the variety most likely to exhibit “regreening” in the spring, where the peel color reverts partially back to green even though the fruit remains fully ripe.
Mandarins and Tangerines
Mandarins and Tangerines, while distinct from oranges, usher in the earliest part of the citrus season. Varieties like Satsuma or Clementine are often ready for picking as early as late September and continue through December. Their early timing makes them a prelude to the main orange harvest.
Indicators of Peak Ripeness and Proper Harvesting Techniques
Indicators of Ripeness
Since oranges do not continue to ripen or sweeten once removed from the tree, accurate determination of ripeness is paramount. The most reliable method is the taste test, where a sample fruit is picked and consumed to ensure a satisfactory balance of sugar and acid. Ripe fruit should feel heavy for its size, indicating high juice content, and should have a sweet, citrusy fragrance. Color alone is an unreliable indicator in Arizona, as the fruit may turn orange due to cold nights before internal sugars have fully developed.
Proper Harvesting Techniques
When harvesting, the correct technique involves using clippers or pruning shears rather than pulling the fruit from the branch. Pulling the fruit can damage the peel at the stem end, creating a wound susceptible to decay and fungal infections. The best practice is to cut the stem as close to the fruit as possible, leaving only a small, smooth piece attached to prevent damage during storage.