A pot experiment was carried out during the winter season of 201 4 under alluvial soil at the green house of Soils Dept. Faculty of Agriculture, MansouraUniversity. The aim of this experiment is to study the response of lettuce plant to different rates of humic substances (humic and fulvic acids).The experiment treatments included four different application rates of humic and fulvic acid (0, 7, 10 and 13 kg fed^-1) using three methods of application (soil, fertigation and foliar applications). The used experimental design was a split plot design with three replicates for each treatment .The effects of soil applications, fertigation and foliar of humic substances on the plant growth and some nutrient elements uptake of lettuce (Lactuca sativa L.) grown under different rates were examined. The results of the present study showed that the significant effects of different application rates of humic substances on   fresh and dry weights, plant height, N%, P % and K%. The results indicated that the highest values of fresh and dry weight of shoot   as well as plant height (cm) were at foliar addition of fulvic acid at 13 kg fed^-1 treatment. Also, the nutrient content (N, P, and K) of lettuce was significantly increased with raising of application rates of humic substances..