Despite their botanical name, Prunus persica, historians believe peaches originated in China before becoming widely cultivated in ancient Persia.
A species in the rose family, peaches have corrugated seed shells placing the fruit in the same subgenus as almonds.
Although Georgia is known as the “Peach State” and has produced statistically significant harvests since the late 1500s, California tops the nation in production, followed by South Carolina, then Georgia, and New Jersey.
Types & Varieties
Velvety skin differentiates peaches from nectarines, which are the same species, but bear a recessive gene that inhibits the tiny ‘peach fuzz’ of its biological sibling.
There are hundreds of peach cultivars growing in the United States, and over 2,000 worldwide. Fruit is classified as either clingstone, freestone, or semi-freestone according to how easily the pit or seed separates from the flesh.
There can also be melting and nonmelting flesh types, referring to how quickly flesh softens and fibers pull away from the stone when ripe. Melting flesh peaches can be either clingstone or freestone and are favored for the fresh market; nonmelting types are better for processing or canning.
Regarding flesh color, there’s yellow (most common in the United States for both clingstone and freestone varieties, usually with a higher acid content), white (growing in popularity, originally cultivated in Asia, and sweeter), and the rare red (lesser known and with limited availability).
Clingstone peaches are juicy, soft, sweet, and often used for processing; varieties include Halford, Indian Blood, Independence, Red Beauty, Santa Rosa, and Sims.
Freestone peaches have a firmer texture, are often larger in size, less juicy, have lower sugar content, and stand up well to heat, making them popular with bakers. Varieties include August Pride, Bonita, Cardinal, Early Amber, Elberta, Frost, Golden Jubilee, O’Henry, Redhaven, “Rio Grande, Santa Barbara, and Veteran.
Semi-freestone varieties include Babcock, Dixi Red, Florida-prince, and Springtime.
Specialty cultivars include donut or doughnut peaches, a type of white-flesh fruit with a distinctive flat shape and preferred for their sweetness, lower acidity, and delicacy.
Dwarf cultivars, which will bear fruit in less time than traditional trees, include Bonanza II, El Dorado, Empress, Galaxy, Golden Gem, Pix Zee, Saturn, and Southern Sweet.
Peach trees grow best in temperate climates with well-drained soil and sloped land for good air circulation. Fields previously planted with soybeans or alfalfa are not recommended due to soil viruses. New trees will not bear fruit for 3 years, but most enjoy an average lifespan of 15 to 20 years.
Mature trees can reach heights and widths of 25 feet and require ample chill hours (ranging from 800 to 1,500 hours) before the onset of warm weather blossoming can begin.
Excess flowers and young fruit should be thinned out (often done by hand to prevent mechanical injury).
Varieties are classified as early, mid, or late depending on the number of days from bloom to harvest; clingstones tend to begin earlier than freestone cultivars.
Pests & Diseases
Although its fuzzy exterior is said to protect peaches, a number of pests are still attracted to the succulent fruit including squash bugs and stink bugs, which bite into developing drupes, leaving tiny marks on immature fruit that can turn into wrinkles as the skin matures.
Most of these imperfections are harmless and occur frequently in organics due to restrictions on pesticide use.
Other pests of concern include aphids, beetles, borers (including the aptly named peach tree borer), caterpillars, cutworms, leaf hoppers, leafrollers, moths, nematodes, scale, and spider mites.
Peaches are susceptible many viruses and diseases including bacterial canker, brown rot, coryneum blight, crown gall, grey mold, leaf curl, mosaic, powdery mildew, root rot, rust, scab, sunburn, and wood decay.
Storage & Packaging
Peaches do not ripen on their own after harvest and should be picked when ripe (though fruit intended for processing can be less mature).
Color (no green left on the skin) and firmness (a slight give to the touch) are external indicators of ripeness. If fruit is harvested too early, it can shrivel. Most trees require multiple harvests; a gentle twist should suffice to dislodge the fruit, without undue pressure as peaches are susceptible to bruising.
Peaches can be stored for 2 to 4 weeks at 31 to 32°F with 90 to 95% relative humidity. Exposure to lower temperatures can cause chilling injury; symptoms include a water-soaked appearance, internal browning, mealy flesh, and flavor loss.
Ink or black stains on the skin can occur if fruit is damaged during harvest and exposed to common metals such iron or aluminum.
References: Oregon State Univeristy, PennState Extension, UC Davis Postharvest Technology Center, University of California Agriculture & Natural Resources, University of Georgia, USDA.
GRADES & GOOD ARRIVAL
Peaches are divided into U.S. Fancy, U.S. Extra No. 1, U.S. No. 1, and U.S. No. 2 grades. All grades stipulate fruit be of one variety, mature, and well-formed (with the exception of U.S. No. 2, which are described as ‘not badly misshapen’).
Generally speaking, the percentage of defects shown on a timely government inspection certificate should not exceed the percentage of allowable defects, provided: (1) transportation conditions were normal; (2) the USDA or CFIA inspection was timely; and (3) the entire lot was inspected.
|U.S. Grade Standards||Days Since Shipment||% of Defects Allowed||Optimum Transit Temp. (°F)|
Canadian good arrival guidelines (unless otherwise noted) are broken down into five parts as follows: maximum percentage of defects, maximum percentage of permanent defects, maximum percentage for any single permanent defect, maximum percentage for any single condition defect, and maximum for decay. Canadian destination guidelines are 15-10-5-10-5.
References: DRC, PACA, USDA.