Production Practices in Almería Greenhouse Production Most of the producers are small family-owned greenhouse operations and have low capital investments, generally producing on a site of 1-1.4 hectares in size. The family companies generally retain low labour costs and have a strong motivation for work. Production and labour requirements are seasonal. The crops are grown continuously from October to July, with production peaks in December-January when tomato, cucumber, green beans, and pepper are harvested, and then again in May-June when melons are in season. Tomatoes and sweet pepper represent the greatest crop area, followed by melons. Producers use a lot of temporary labour, especially from north Africa, Central and South America. Certain eastern European groups are also migrating to southern Spain for work. There have been recent clashes between growers and mainly Moroccan immigrants, due to poor working and living conditions for foreign labourers. Several growers have faced strikes, and labour issues appear to be some of the greatest problems facing producers in the area. Approximately 90% of the greenhouses use an artificial soil called Enarenado in order to overcome the extremely poor indigenous soils of the region. This is a soil mix of clay, manure and sand that sits on top of the original soil base. In the remaining greenhouses, plants will never touch soil - they grow using a hydroponics system where chemical fertilisers are drip-fed to each plant from large, computer-controlled vats. Water quality is a prime factor in determining the price of land in Spain. Greenhouse production has a requirement of 800-1000 mm per year in a region that receives just 200 mm of annual rainfall. Water efficiency has improved dramatically, especially with the use of drip irrigation, and a new seawater desalination plant opening in 2009 will supply 60,000 m³/day of fresh water to the region. Production and Transport Costs Almería has a comparative advantage over northern Europe with production costs less than half of those found in Holland. Energy costs are low, greenhouses are often homemade and labour costs are one third of those in the Netherlands. Transport costs, however, are nearly doubled, leaving total costs for production and transport 20% less than those in the Netherlands. British Supermarkets Supermarkets British supermarkets are secretive about how much produce comes from Almería. Tesco calls this "commercially sensitive information". But Rafael Losilla, editor of a local farming magazine, names Tesco, Waitrose and Sainsbury's as valued customers. "Britain is the third-biggest export market after France and Germany," he says.