Date palm plants require a rather long acclimatization program of about 15–24 months before transplanting them to the nursery or to the open field conditions. The results of the present study showed that Pentakeep significantly increased the growth of plants as measured by fresh weight, dry matter, plant length, stem diameter and leaf width at both VP2- and VP3-stage (Table 2 and Fig. 1). Such effects were not, however, detectable at the VP1-stage. Plants treated with Pentakeep, especially at 0.04 and 0.08%, developed faster (13 months from transplanting) and were ready for transplanting to the nursery or to the open field conditions about 4–5 months earlier than the control or those treated with 0.02% Pentakeep (Table 2 and Fig. 1). These promotive effects of Pentakeep might be attributed to an increase in light harvesting efficiency and assimilation rate of the treated plants. Chlorophylls concentration and chlorophyll a/chlorophyll b ratio were significantly increased by Pentakeep application compared to the control (Table 3).