Agricultural research linked to government policies to increase the availability of biomass to provide food, forage and medicine requires a re‐think. In particular, by ignoring trees and gathered foods, policies have not met demands for food in arid areas, and an emphasis on increasing production per unit area has accentuated seasonality of production by favouring selection of crop species requiring longer periods of moisture availability. The use of plants for medicines, stimulants and control of fertility also has important seasonal effects, but has received minimal attention to date. The classification of Raunkiaer, who distinguished plants on the basis of their modes of protection and size of buds, enables an analysis related to their effective use of moisture and temperature, so providing a framework for linking the seasonal production of biomass to human needs.