Maximum castorbean (Ricinus communis L.) yields were obtained from combinations of chemical and mechanical treatments. The rotary hoe controlled weeds when used preemergence and during the early stages of crop growth. The flame cultivator gave preemergence weed control and was selective on weeds less than four to five inches tall after castorbeans had attained a height of 12 to 14 inches. The cultivator controlled weeds between castorbean rows, but weeds were occasionally found within the row. 2-Chloroallyl diethyldithiocarbamate gave unsatisfactory preemergence weed control. Ethyl N,N-dipropylthiolcarbamate (EPTC) gave excellent weed control, injured castorbeans at 3 lb/A, but not at 2 lb/A. N-1-naphthylpthalamic acid at 4 lb/A gave good early weed control.