The experiment was conducted during the period from January 2006 to June 2007 on tissue culture-derived plants of the commercially important ‘Khalas’ date palm cultivar at the Date Palm Research and Development Unit(DPRDU),and the Horticulture Laboratory of the College of Food and Agriculture, UAE University (Al-Ain, UAE). On 4th January 2006, uniform tissue culture-derived plants were transplanted in paper pots (9 cm 8 cm),maintained in a greenhouse (28 8C and 80–90% relative humidity, 40% shade net allowing an average PAR of about 600 mmolphotonm2 s1) and received the normal acclimatization program (including irrigation, fertilization,and disease control)developed by DPRDU. All the plants were fertilized with NPK (20:20:20 plus trace elements) at 400 g/ 100 L water (300 mL/pot) once a month.