Grafting cucumbers onto low temperature tolerant rootstocks Cucurbita ficifolia and Sicyos angulatus promoted vegetative growth and early fruit production at suboptimal temperatures in winter. The positive effect of grafting. onto C. ficifolia on length growth and leaf initiation depended on the genotype of the scion. Lines which benefit much from the grafting may possess a relatively inefficient root system to sustain growth of the shoot. At normal growing temperature in winter, S. angulatus as a rootstock drastically reduced leaf necrosis of powdery mildew resistant cucumbers, especially when the plants were grown on rockwool. The reduction of necrosis of the leaves was accompanied by a higher fruit yield. In rockwool grown plants, the concentrations of Mg, Mn and Cu in the xylem sap were much higher in grafted plants, while no clear systematic differences were found in plants grown in soil. Further studies may possibly demonstrate a relation between these differences in the xylem sap and the intensity of necrosis. Detailed studies of rootstock-scion interactions could result in lower costs for the glasshouse cucumber cultivation.