Two field trials were carried out to study the effect of 12 treatments represented the combination
between thee bulb sizes of Hippeastrum vittatum (small, medium, and large.) and four rates of NPK chemical
composition (0, 2, 4 and 6 g/plant) on the growth, flowering, bulbs productivity and chemical composition of
Hippeastrum vittatum plant. Results showed that the combination of the large bulb size significantly induced the
greatest values of plant height, leaves number and fresh and dry weights, particularly those treated with chemical
fertilizer at the highest rate in the two seasons. The earliest flowering was recorded by the combined treatment
between large bulb size and chemical fertilizer at 6g/L, followed by the combined treatment between large size
and chemical fertilization at 4g/plant in the two seasons. Furthermore, the combination of large bulb size scored
the highest values of inflorescence length, inflorescence stem diameter, inflorescence fresh weight and flowering
percentage, especially those received chemical fertilization at the high rate in the two seasons. The highest results
of bulb and bulblet diameter, bulb fresh and dry weights and number of bulblets / plant were detected with the
combinations of large bulb size, especially those received chemical fertilization at the high rate in the two seasons.
The highest leaf N, P, K. total carbohydrates and total chlorophylls contents were scored by the combined
treatment between large bulb size and chemical fertilization at 6 g/plant in the two seasons. Conclusively,
fertilizing Hippeastrum vittatum plants with mineral fertilization with N: P: K at 6g/L induced prospective effects
on vegetative growth and flowering parameters with higher bulbs productivity.