An experiment was established to study the influence of humic acid (HA) application at different rates (0, 1.5, 3.0 and 4.5 g/l) on vegetative characters and the production of black cumin (Nigella sativa L.) sown on three different dates (15^th Oct., 1^st and 15^th Nov.). The plants cultivated on the first date (15^th October) gave the best results compared to the late dates concerning plant height (61.54 and 55.34 cm), branch number/plant (4.42 and 3.62), stem diameter (5.71 and 4.42 mm), number of capsules/plant (18.10 and 16.75), seed yield/plant (8.70 and 8.92 g), total seed yield/feddan (464.03 and 475.38 kg), fixed oil percentage (19.88 and 17.28 %), fixed oil/plant (1.76 and 1.59 ml), fixed oil/feddan (93.88 and 84.52 l), chlorophyll a (0.57 and 0.57 mg/g), chlorophyll b (0.30 and 0.75 mg/g) and carotenoids (0.32 and 0.43 mg/g) during both seasons respectively. Foliar application of HA in medium rate (3 g/l) gave the best productivity of the same previous parameters compared to the lower and higher rates: plant height (58.46 and 53.33 cm), branch number/plant (3.90 and 3.65), stem diameter (5.57 and 5.00 mm), number of capsules/plant (14.94 and 14.67), seed yield/plant (8.26 and 9.13 g), total seed yield/feddan (440.62 and 486.70 kg), fixed oil percentage (26.63 and 23.30%), fixed oil/plant (2.20 and 2.11 ml) and fixed oil/feddan (117.26 and 112.67 l) during both seasons respectively. The application of humic acid in the medium concentration on black cumin sown in mid-October seems to be the best interaction for getting higher seed yield and a high percentage of fixed oil.