Applications of silicon (Si) and potassium humate (K-H) plays essential roles for enhancing many plants agronomic parameters and yield as well as quality characteristics under poor fertile soil conditions. This investigation carried out during 2019 and 2020 summer seasons at North Delta, Biyala district as a poor fertile soil located at Kafr El-Sheikh, Egypt. This investigation aims to evaluate the efficacy of foliar application of silica forms [Traditional-Si (T-Si) and Nano Si (N-Si)] with various concentrations (control, 250, 500 and 750 ppm/liter) combined with or without potassium humate (K-H) as single concentration 14 cm³/liter through (tillering, panicle formation and heading stages) on growth, yield and grain quality of Giza 178 rice cultivar. A split-plot design based on randomized complete block for treatment arrangement with three replicates was used. Two Si forms were designated in main plots, while the concentrations along with or without potassium humate were arranged in sub plots. Data obtained revealed that foliar application of nano silica (N-Si) showed a remarkable superiority with regard to all growth, yield and grain quality parameters in both seasons of study. When the foliar application of Si concentrations increased up to 750 ppm/L cause significant increases in the growth, yield and its components as well as grain quality. Concerning interaction effect, foliar application of Nano Si with potassium humate (K-H) surpassed the remaining treatments and recorded the peak values of growth and other yield and grain quality parameters. Coefficient of determination (R²) also illustrated that, there were obvious relationship between foliar application of silicon forms and number of panicles/m² (0.6431and 0.7432), panicle length (0.7556 and 0.7921), panicle weight (0.7416 and 0.6941), number of filled grains/panicle (0.7667 and 0.8586) as well as grain yield (0.8485 and 0.8793) for both traditional and nano silica foliar concentrations. In the same trend, coefficient of determination recorded a positive relationship between all silica forms and their concentrations in terms of elongation % (0.5085 and 0.5603) and vice versa was recorded in case of amylose content (0.1788 and 0.1167) for both foliar application of traditional and nano silica, respectively. Whilst, a significant sturdy positive correlation between grain yield with each of number of panicles/m² (r = 0.912), panicle length (r = 0.913) and panicle weight (r = 0.857). From the obvious results it could be conclude that foliar application of Si forms with 750/L ppm along with potassium humate with 14 cm³/L through the vital (tillering, panicle formation and heading stages) could be the suit avenue to achieve high grain yield and pertinent quality of Giza 178 rice cultivar under poor soil fertile condition in North Delta, Egypt.