Bitter melon is an annual climber with a profusion of yellow flowers. The fruit is cucumber shaped with a number of irregular longitudinal ridges and a varied warty skin depending on the variety. The fruit colour ranges from white through light green to dark green. Identifying maturity is a big problem for bitter melon. Consumers prefer a full-sized immature fruit. When mature the fruit ripens quickly and is inedible. The only reliable indicator is the seed colour that goes from white to pink and then red when mature.