The experiment was carried out under plastic house conditions during autumn seasons of 2016 and 2017 at the Agricultural Experiment Station, Faculty of Agriculture, Cairo University and Laboratory of Handling of Vegetable Department, Horticulture Research Institute, Giza Governorate, to study the effect of foliar spray with potassium silicate at different concentrations on vegetative growth, yield and its components, fruit quality and storability of cucumber fruits (Cucumus sativus L.) Hisham F₁ hybrid. The results indicated that foliar spray with potassium silicate at 4% or 3% significantly increased vegetative growth parameters (plant height, number of leaves/ plant, fresh weight of plant and chlorophyll reading (SPAD) in leaves, silicon and potassium contents in the leaves, yield and its components (fruit weight and total yield / plant), physical and chemical properties of fruit and silicon and potassium contents in fruits as compared with other treatments or untreated plants (control). Potassium silicate at 4% improved storability of cucumber fruit (reduced weight loss, color change and maintained fruit firmness, TSS and V.C) and exhibited good appearance after 15 days of storage at 10^o C.