They are warm season annuals, highly branched and having trifoliate leaves like the other legumes. Both upright and vine types of growth habit occur in mungbean, with plants varying from one to five feet in length. Self pollination occurs so insect and wind are not required. Mature seed colors can be yellow, brown, mottled black or green, depending upon variety. These round to oblong seeds vary in size from 6,000 to over 12,000 per pound, depending upon variety.
Germination is epigeal with the cotyledons and stem emerging from the seedbed.
Adequate rainfall is required from flowering to late pod fill in order to ensure good yield. Late plantings which result in flowering during the high temperature-low moisture period in July and August will reduce yield. High humidity and excess rainfall late in the season can result in disease problems and harvesting losses due to delayed maturity. Mungbeans are responsive to length of daylight so short days hasten flowering and long days delay it. Varieties differ in their photoperiod response.