The effects of the treatment of irrigation at different intervals (every 3, 6 and 9 days) in interacted with foliar application treatments (tap water as control, potassium silicate at 1 and 2 % as well as salicylic acid at 25 and 50 ppm) on growth, root parameters and some chemical constituents of Dieffenbachia pictawere investigated. The current search was carried out at Horticulture Research Station at Mansoura, Dakahlia Governorate, Egypt, for two summer consecutive seasons of 2019 and 2020. Attained results referred to that irrigated dieffenbachia plants every six days significantly increased plant height, leaf length, leaf width and leaf number per plant at both seasons after three and six months from repotting date compared to the other irrigated intervals under study. Furthermore, the highest values of average of leaf area, root length, dry roots weight per plant as well as total chlorophyll, carotenoids and proline contents were obtained by the treatment of irrigation every 6 days. In addition, the highest values of above-mentioned parameters were recorded by foliar spray of potassium silicate at 2 % concentration compared with the other concentration of both potassium silicate and salicylic acid under study. In any case, the better growth and root parameters, higher chemical constituents (total chlorophyll, carotenoids and proline) could be obtained by spraying potassium silicate at 2% concentration on irrigated dieffenbachia plants every six days.