A convex reflective surface, such as mirror (1) or an equivalent deflector of radiation, designed to suit a FIG. 5 particular location or type of location, fixed in position and requiring no adjustment, can re-direct solar radiation (2,3) downwards onto a chosen target area throughout the calendar year or such lesser period of operation as may be chosen, benefitting the growth of plants in a greenhouse or the open air, and other human activities, at minimal expenditure including of fossil fuel.