An experiment was conducted at Andalas University area to evaluate the efficacy of plant extracts on the growth and yield of maize. The first trial was testing the crude extracts of several plants on vegetative growth of maize factorial completely randomized design (CRD). The first factor crude extract sources from five species of plants, and the second factor was levels of extract concentration. The second trial was application of the purified extracts on growth and yield of maize using factorial CRD. First factor was the purified extract concentrations, and second factor was application frequencies. Results showed that application of 100 mg/L crude extract of Gleicheni linearis leaves was the most effective in increasing plant height and leaf area, compared to control. Treatment with 100 mg/L crude extract was better than the purified one. However, application of purified extract resulted in lower growth and yield of maize compared to control. The highest growth and yield attributes were recorded in 100 mg/L crude extract of G. linearis when applied at 15 days after planting (DAP). Further experimentation is needed for confirmation of the results.