A pot experiment was conducted to study the response of squash (cucurbita pepo L.) to potassium phosphite and potassium fulvate as single treatments or in a combination with each other. The treatments included: potassium phosphite as a single treatment at four concentrations (C1: 0, C2: 0.1, C3: 0.2 and C4: 0.4 ml plant^-1), potassium fulvate as a single treatment at four concentrations (C1: 0, C2: 6, C3: 9 and C4: 12 kg fed^-1), and the combined treatment of potassium phosphite with potassium fulvate at four concentrations (C1:0, C2: 0.05+3, C3: 0.1+4.5 and C4: 0.2 ml plant^-1+6 kg fed^-1, respectively using soil and foliar applications. The results indicated that the combined treatment of potassium phosphite with potassium fulvate was more effective in increasing of all investigated parameters. At the flowering stage, the highest values of fresh weight (214.96g), dry weight (13.31g), plant length (70.83cm), total leaf area (2547.12cm²) and the nutrients concentrations of (N, P and K%) (5.17,0.72 and 6.50%) were achieved with the combined treatment at C3 using soil application. At the harvesting stage, the highest values of fresh, dry weigh, total leaf area and (N, P and K) were 346.87g, 29.00g, 4720.56cm² and (3.95, 0.62 and 4.43%), respectively, using the combined treatment at C2 as soil application, while the value of plant length was (88.67cm) with the combined treatment at C3 using soil application. The highest values of total yield, dry weight and the characteristics of squash fruit (length, diameter and weight) were 475.67g,19.13g and (16.30cm, 3.63cm and 115.95g), respectively using the combined treatment as foliar application at C3, the combined treatment at C2 as soil application gave the highest values of N,P and K in fruits, these values were 4.12,0.71 and 5.99%. Also, the highest values of available N, P and K mg kg^-1 and OM content gkg^-1 were 70.70, 12.83 and 423.73 mg kg^-1 and 13.5 gkg^-1, respectively with the combined treatment at C4 using soil application.