Rates and Methods of Application of Nitrogen and Phosphorus for Commercial Field Production of Head Lettuce in Southcentral Alaska

Abstract

Head lettuce (Lactuca sativa L.) is one of the major agricultural crops grown in Alaska. In 1992, its wholesale value was approximately $314,000, second only to potatoes among Alaska’s commercially field grown vegetables (Brown et al., 1992). The quality of head lettuce is as important as yield, as lettuce heads that do not meet minimum size and weight standards are unmarketable. Head size and weight are strongly influenced by management practices, dictating a high level of management for successful commercial production. Among manageable cultural variables, rate of fertilizer application and the method of fertilizer placement are two of the most critical. Despite the value of the head lettuce crop to Alaska vegetable growers and the importance of fertilization as a management practice, little research has been published on rates of application and method of applying nitrogen and phosphorus to commercially grown head lettuce.