Abstract: This invention describes a method and apparatus for the capture, storage and release of carbon dioxide for use in the horticulture industry, the method including reduction of a transition metal oxide to form a transition metal and carbon dioxide; carburization or partial carburization of the transition metal to form metal carbide; carbonation of an alkaline metal oxide or alkaline earth metal oxide to form an alkaline metal carbonate or alkaline earth metal carbonate; contacting the metal carbide with air to produce a transition metal oxide and carbon dioxide; and calcining the alkaline metal carbonate or alkaline earth metal carbonate to form carbon dioxide and alkaline metal oxide or alkaline earth metal oxide. Also described is a sorbent material for use in the method and apparatus of the invention.