effect of humic acid and yeast on the yield of greenhouse cucumber

Purpose: cucumber is a very sensitive plant even under standard conditions, and its fruit, reaches the harvest stage rapidly. in addition to, in yemen a lot of fertilizer and fungicide chemical have used during the production. for this purpose, effect of exogenously applied of bio-stimulators (humic acid and yeast) was examined. research method: cucumber hatem f1 cultivar was used as plant material. plants were grown during the clean horticulture practices under polyethylene greenhouse condition. the experiment designed as completely randomized blocks design (rcbd). humic acid at 0, 100 and 300 mg l^-1, as well as yeast at 0, 2000 and 4000 mg l^-1, sprayed once alone or in combination. findings: as compared to control, humic at 100 mg l^-1 alone increased the yield about 14.88%. yeast at 4000 mg l^-1 alone offered the significantly (p≤0.05) highest of the plant (88.2%) and higher yield (91.00%). yeast at 2000 mg l^-1 significantly increased leaves dm% (26.6%). yeast significantly increases chlorophyll spad. the interaction of 100 humic × 4000 mg l^-1 of yeast increased the yield by 168.26% than the control. research limitations: further studies were needed to clarify the interaction effect of both substances by using the higher modern technique. originality/value: the finding obtained from this study could probably use to manage and successfully applied to the production of organic cucumber. moreover, it could be suggested that the combination between yeast at 4000 mg l^-1 and humic at 100 mg l^-1 is the best for the productivity of cucumber.