In the growing and processing of canning peas there are many factors which influence yield and quality. Of these, the stage of maturity is possibly the most important. Beyond the stage of maximum quality, peas continue to grow in size and yields increase but quality decreases. Consequently, both growers and processors are definitely interested in knowing the stage of maturity at which peas should be harvested for the greatest yield of acceptable quality. Peas harvested and processed at that stage should give both growers and canners the maximum returns if grading methods are satisfactory and price schedules equitable.
Pollard, L. H.; Wilcox, E. B.; and Peterson, H. B., "Bulletin No. 328 - Maturity Studies with Canning Peas" (1947). UAES Bulletins. Paper 289.