Updated July 2008 by Diane Huntrods, AgMRC, Iowa State University.
Overview
The common date (Phoenix dactylifera) is believed to have originated in the Arabian Gulf between the Nile and Euphrates rivers. Nomads planted dates in the desert, and Arabs introduced them to Spain. Ever since, they have been grown on the French Riviera, south Italy, Greece and Sicily. As of 2005, the major date-producing countries were (in order): Egypt, Saudia Arabia, Iran, United Arab Emirates and Pakistan.
California was the first state to plant seedling dates after Spanish explorers introduced dates to Mexico. In 1890, the first offshoots reached California from Egypt, and Arizona started to grow dates in Phoenix and Tempe. California and Arizona now lead the nation in date production.
Commercial production of dates in 2007 totaled 16.3 thousand tons in California. Due to a significant increase in price, $860 per ton in the last two years, fig production in the state was valued at $37 million. Meanwhile, commercial production of dates in 2006 totaled 40 thousand pounds, the largest crop since 2002, for the entire United States.The number of acres planted to date palms, nearly 6 thousand, has also been increasing since 2002. However, per person consumption of dates in the United States has not increased. Of the dried fruits, date consumption per person is only 0.14 pounds, following (in order) raisins and prunes.
Production
Pollination and Thinning
Dates are naturally wind or insect pollinated, and natural pollination can be practiced in seedling orchards with 1:1 ratios of males to females. In most commercial orchards, however, only one male is grown for every 50 females, and pollination is accomplished artificially. The traditional method involves cutting several pollen clusters from the male tree and inverting them among clusters of female flowers. While this practice was performed by hand for centuries, today there are machines that have made the process quicker and easier.
Only female date palms bear fruit, so for commercial purposes farmers plant predominantly female trees. However, male trees that produce plentiful pollen are very valuable, because the quality of the male pollen influences the size of the fruit and the rate at which it ripens.
Fruit thinning is practiced at pollination time or sometimes 6 to 8 weeks after pollination. Thinning is accomplished by bunch thinning, where some strands or portions are removed, by complete bunch removal or both.
Planting and Pruning
Traditionally, new date trees were grown from the pits of dates or offshoots from the tree. Scientists have now devised a method for growing date trees from tiny pieces of the heart of the palm that are cultured in the laboratory.
Dates are planted about 25 to 35 feet apart, yielding about 50 plants per acre on average. However, varieties such as 'Khadrawy' can be planted at higher densities. Persistent leaves and old fruit stalks must be pruned off.
Fruit
The date palm begins producing fruit when it is about seven years old and generally continues to produce for 75 years, although the tree itself may live to be 150 years old. Dates grow in clusters below the fronds of a date palm tree. The fruit is 1 to 3 inches long, thick skinned, with thick sweet flesh and a large seed in the center. Each bunch of dates contains hundreds to thousands of fruit that weigh about 80 pounds. Because each tree produces between five and ten bunches, a mature female tree can produce upwards of 150 pounds of fruit annually.
Climate
Date palms must have full sun; they cannot grow in the shade. The fruit must be produced commercially at a temperature of 90 degrees F with no rain or less than ½ inch of rain during the ripening period. Dates can tolerate long periods of drought.
Harvesting
During development, dates progress through five maturity stages that take about 6 to 8 months: (1) Fruits grow rapidly, (2) Turn their characteristic color, (3) Lose water, (4) Accumulate sugar and (5) Ripen completely. In California, dates are harvested from August through March.
Although dates are historically a labor-intensive crop, modern high-tech processing allows producers to handle the large volume. For post-harvest handling, immature and damaged fruit are removed. In rainy regions, fruit are harvested earlier and dehydrated. In hot regions, dry winds dehydrate the fruit.
For fresh shipment in California, the normally ripe, harvested fruits are transported to packing plants, weighed, inspected by USDA agents, fumigated, cleaned, graded, packed, stored under refrigeration and released to markets according to demand.
Grading
United States standards for grades of dates range from grade A fancy to grade B choice to grade C standard, based on uniformity of color and size, absence of broken skin and insects.
Nutritional Value
Moist or ripe dates are rich in iron, niacin, phosphorus, vitamin A and vitamin C. If dried, the amounts of calcium, fiber, iron, niacin, phosphorus and protein are almost doubled. Dates are known for their digestive properties, such as aiding the growth of useful colon bacteria and as a laxative.
Value-added Products
Dates lend themselves to a wide variety of value-added food products, including date paste, date sugar, date syrup and date vinegar. In some regions, cull dates are used in livestock feed. The leaves of date palms have numerous traditional uses.
Date Paste
Date paste is a condensed product extracted from dates by water evaporation. The paste contains all the same vitamins and minerals as the dates. The paste is used in various industries as a thickener or gelling agent in confectioneries and jams. Nowadays, date paste has became a sweetener, an alternative to sugar due to its fiber, minerals and vitamins.
Date Sugar and Date Syrup
Date sugar is used as a natural sweetener instead of refined sugar. Date syrup, a sweet liquid product, is used like maple syrup to complement pancakes or bread, to top ice cream or to mix with milk.
Date Vinegar
Date vinegar was made 5,000 years ago in Babylonia (Iraq). The fruit ferments readily, making dark, rich vinegar that has a fruity flavor. It can be used like balsamic vinegar.
Cull Dates
Cull dates are dehydrated, ground and mixed with grain to form a very nutritious stockfeed. Dried dates are fed to camels, horses and dogs in desert regions.
Palm Buds and Leaves
The date tree's terminal buds, known as hearts of palm, make tasty additions to vegetable salads. In some European countries, groves of date palms are maintained solely to supply young leaves for religious use. Mature leaves and midribs were traditionally made into mats, screens, baskets, crates and fans.
Exports and Imports
The United States chiefly exports two varieties of dates, the 'deglet nour' and 'medjool,' to the European Union (EU). Although the EU import of dates represents only 10 percent of world imports in volume, it accounts for some 30 percent in value. This reflects the fact that EU import prices for dates are much higher than the world average. In 2006, the United States exported 6.9 million pounds of dates, a decrease of 2.2 million pounds from 2005, while the country imported 15.3 million pounds, an increase of 4.1 million pounds from 2005.
Trends
In California, production has been characterized by the gradual transition of private, individual ownership of the date plantations into large holdings by companies integrated with large-scale packing and processing facilities. There are exceptions to this trend, however, and several individual farmers grow, pack and sell their fruit on the spot in roadside stores.
Due to increasing labor costs, another major change that has taken place in U.S. date cultivation has been the mechanization of cultural practices, especially the timing and method of harvesting. Today, in many instances, the dates are left on the palm longer and are harvested at the same time.
Prepared August 2007 and revised July 2008.