The most important horticultural crops grown in Spanish greenhouses are tomatoes and peppers for fresh consumption. These crops tend to be grown as monocultures and have achieved high levels of specialization in some coastal regons of the Spanish Mediterranean as is the case of the tomato in the Mazarron region (Murcia) or the pepper in campo de Cartagena (Murcia and Alicante), whereas in Almeria, there is greater crop diversification. In fact, Almeria is considered to be the region with the largest concentration of greenhouses in the world ; the surface area of the greenhouses has increased gradually, reaching 38,780 ha (MAPA,2006)