lettuce, head lettuce, lettuce variety tests, lettuce variety trials, McCrory
Head lettuce is a crop that would have greater possibilities in South Dakota if its limitations were better known. One of the main problems in growing head lettuce is the selection of a quick heading variety of good quality and good yield If the plants are grown at temperatures above 80 ° F., they tend to send up seed stalks instead of heading. Soft rots also develop at temperatures above 80°. This circular reports the results of a test of standard varieties and strains, as well as the investigation of plant growing practices that would encourage maximum heading of lettuce varieties before temperatures exceed 80° F. Also reported is the influence of fertilizers and manure in hastening maturity. By starting lettuce seed indoors March 15, April 1, and April 15, Snyder (I) was able to mature plants 9 to 15 days earlier than field sown seed. Preliminary work showed that seed sown March 15 and seedlings transplanted outdoors gave the largest harvest of heads when compared with later sown seed started both indoors and out (2). As a fall crop, head lettuce does not appear to be dependable.
South Dakota State College of Agriculture and Mechanic Arts, Agricultural Experiment Station
McCrory, S. A., "Head Lettuce Varieties and Cultural Practices" (1950). Agricultural Experiment Station Circulars. 77.