The present investigation were carried out in the two successive summer growing seasons 2018 and 2019 on potato plant, CV. Sponta, at South El- Tahrir district, newly reclaimed sandy soils at the experimental station farm, Horticulture Research station Beheira Governorate to study the influence of irrigation treatments and humic acid (HA) application at different growth stages on vegetative growth, yield potential,  tuber quality, water requirements and water utilization efficiency (WU_tE) of potato plants. Nine irrigation treatments were applied at three periods, (S₁) vegetative growth, (S₂) tuber formation and (S₃) tuber bulking. Results revealed that there were significant effects due to the irrigation and humic acid treatments and their interactions on potato production in both growing seasons. T1 irrigation treatment gave the mean highest values of vegetative growth traits (plant height, number of branches, fresh and dry weight of plant, yield/plant, and number of tubers plant^-1, average tuber weight, yield/feddan, and tuber diameter). Application of humic acid (HA) resulted in improving vegetative growth characters, in both seasons. Water stress treatments at S1 generated the lowest mean values of all vegetative growth characters, which illustrated that this stage is sensitive to water stress treatments. The interaction between irrigation treatments and HA reflected significant differences on the studied vegetative growth parameters. The interaction of T1 treatment and HA application showed superior influence on vegetative growth traits, in both growing seasons. On the other hand, the highest mean values for tuber content of starch were obtained by Ta and HA application.