The effect of different concentrations of aqueous extracts of leaf, stem, and root of Leucas aspera L. on seed germination and seedling growth of Cajanus cajan. The result revealed that the aqueous leachates of leaf, stem and root of high concentrations significantly inhibited germination, growth and fresh weight of seedlings. But at low concentrations (5%, 10 and 15%) the same leachates promote both germination and seedling growth of Cajanus cajan. The inhibitory effect of various concentrations of aqueous leachates was found to be concentration dependent. Hence it is known that the weed, L. aspara naturally growing in crop fields of Cajanus cajan has some influence over the germination behavior and seedling growth of crop.