A pot experiment was conducted under plastic house conditions at the Nursery of Bot. Gardens Res. Dept., Hort. Res. Inst., ARC, Giza, Egypt during 2021 and 2022 seasons to study the effects of planting in the following media: sand (S) alone as control (M0), S + bentonite (B) at 3:1, v/v ratio (M1), S + organic compost (OC) at 3:1, v/v ratio (M2), M2 + 10 ml/l EM biostimulant (M3), S + B + OC at 2:1:1, v/v/v ratio (M4) and M4 + 10 ml/l EM biostimulant (M5), irrigation frequencies at thrice a week, twice a week and once a week and their interactions on growth and chemical composition of the dwarf umbrella tree (Schefflera arboricola Endl.) transplants. The obtained results indicated that in both seasons amending the sand with either bentonite or organic compost or both improved the mean values of various growth traits over control means in most cases both seasons, with the prevalence of M4 and M5 mixtures, which gave the highest values compared to the control. The plants irrigated thrice or twice a week had better growth than those irrigated once a week, with the dominance a week water treatment, which recorded in most growth characteristics. It was also, noticed that the various single and combined treatments raised chlorophyll a, b, carotenoids, total carbohydrates, N, P, K and proline concentrations in the leaves, with some exceptions relative to control, but the superiority was M4 or M5 mixture, with irrigating thrice or twice a week and their interactions, which acquired the utmost high concentrations over the other individual and combined treatments. Accordingly, it can be recommended to culture Schefflera arboricala Endl. transplants in a mixture of sand + bentonite + organic compost (2:1:1, by volume), with 10 ml/l EM biostimulant and irrigating them either thrice a week (when water is available) or twice a week (at water shortage) to get the best growth appearance and high quality of potted Schefflera plants.