The researchers studied how extracts from different parts of hot pepper plants affect the germination of four types of vegetable seeds. They found that low concentrations of hot pepper extract improved Chinese cabbage and radish seed germination, but higher concentrations inhibited all four vegetables. The order of allelopathic effects from hot pepper parts on seed germination was leaf, stem, plant, and root. Tomato and Chinese cabbage seeds were sensitive to hot pepper chemicals, while radish and cucumber seeds were not.