The effect of sowing date and season on the development and yield of Navy beans (Phaseolus vulgaris) in south-east England

Abstract
SUMMARY: The results of experiments in which Navy beans (cv. Purley King) were precision drilled at the beginning, middle and end of May in 1972, 1973 and 1974 suggest that the optimum time to sow is mid-May when soil temperatures at 10 cm depth have reached 12–13 °C. Earlier sowing usually led to a reduced plant stand and low yields whilst in 1972 and 1974, two exceptionally cool years, later sowing resulted in lower yields following a reduction in 1000-seed weight.Despite contrasting weather conditions acceptable yields of seed were obtained in all 3 years from mid-May sowings although cool wet conditions in the autumn of 1974 curtailed drying of the seeds below 30% moisture content. Accumulated temperatures (Ontario units) were successfully used to predict stages in crop development and the data used to demarcate the areas in England most suitable for Navy-bean production.