Head Lettuce.pdf

This production summary provides an overview of head lettuce growing, harvesting, and post-harvesting practices. Head lettuce varieties, such as iceberg and butterhead, are planted according to market demand and historical success in specific growing regions. Nearly all commercially produced head lettuce in the US comes from California and Arizona, with optimal growing temperatures between 73°F and 45°F. Lettuce grows best in silt loams and sandy soils with good drainage. Prior to planting, soil is amended to loosen clods and improve quality, and fields are prepared using various implements. Lettuce is typically planted using pelleted seed with a precision planter, and growers thin the density of growing plants to reduce disease. Irrigation practices vary, with many using ground water or surface water, and crops are irrigated every two to three days until seedlings emerge. Commercial growers use chemical fertilizers or composted organic materials, and weeds and insects are controlled using herbicides, pesticides, and traps. Head lettuce is harvested mechanically or by hand, and is not washed. After harvest, lettuce is cooled as soon as possible using forced air cooling, hydro-cooling, vacuum cooling, or evaporative cooling to maintain quality and prevent decay.