Phoenix dactylifera

Cultivation Details

Date palm is a plant of drier areas in the tropics, where it is found at elevations up to 1,500 metres. Hot dry conditions are required for free fruiting, the fruit not forming very readily in cooler or moister climates^[1]. It grows best in areas where annual daytime temperatures are within the range 26 - 45°c, but can tolerate 10 - 52°c^[2]. When dormant, the plant can survive temperatures down to about -15°c, but the leaves and young growth can be severely damaged at -4°c^[2]. It prefers a mean annual rainfall in the range 200 - 300mm, but tolerates 100 - 400mm^[2]. The tree transpires large quantities of moisture and the amount of available rainfall is often little, or entirely absent in the production areas. The water requirement of the palm must be provided for by ground water (the roots of the tree can reach 2 - 6 metres deep) or by irrigation^[2]. Plants are tolerant of a range of soil types^[3], so long as they are well-drained^[1]. Plants grow well in full sun, even when small^[1]. Tolerant of salty soils, though fruit quality might be adversely affected^{[4, 5]}. Prefers a pH in the range 6.5 - 8, tolerating 6 - 8.5^[2]. The plant has escaped from cultivation and become established as a weed on several Pacific Islands, including Hawaii^[6]. Seedlings begin to develop a stem when about 4 - 5 years old and will usually start flowering soon afterwards^[5]. Plants propagated from suckers can commence fruiting within 2 - 4 years and normally reach full production at 5 - 8 years, although productivity may increase up to 9 - 15 years^[2]. Pollination is critical for good fruiting; therefore, pollen is usually artificially introduced to the female flowers by cutting a male inflorescence and placing it strategically within a female inflorescence - this may be thinned a little to accommodate it. It is important that male trees are planted with females in ratios of about 1:50 in order to provide sufficient pollen^[5]. An average well-managed palm can produce about 60 - 70 kilos of fresh dates per year^[2]. Commercially, yields of dates are often restricted to about 50 kilos per tree in order to ensure high quality, though yields of 100 kilos have been recorded^[7]. Yields decline after 40 - 50 years, but the tree will continue to produce until about the age of 75 years^[2]. When fruit yields are poor, the tree is often tapped for its sap. The yield varies with management and site conditions, but it is in the range of 4 - 8 litres per day^[5]. There are many named forms^[7]. Phoenix species are quite liable to hybridize where the various species meet as a result of cultivation^[8]. A dioecious species, at least one male plant for every 6 females is necessary to ensure fertilization^[1].