Cotton was a demanding crop because of its long growing season. Slaves plowed the land in March, dropped seeds in early April, and once the plants began to grow, continually chopped away the surrounding grasses. In between these tasks, they planted the corn and peas that would provide food for them and the plantation's hogs and chickens. When the cotton bolls ripened in late August, the long four-month picking season began. Slaves in the cotton south worked much harder and more unremittingly than those in the tobacco regions. Moreover, fewer of them acquired craft skills than in tobacco, sugar and rice areas, where slave coopers and engineers made casks, processed sugar, and built irrigation systems. To increase output, profit-seeking cotton planters began, in the 1820s, to use the gang-labor system. Previously, many planters had supervised their workers sporadically or assigned them specific tasks to complete at their own pace. Now, masters with twenty or more slaves organized disciplined teams or gangs supervised by black drivers or white overseers. They instructed the supervisors to work the gangs at a steady pace, clearing and plowing land or hoeing and picking cotton. If this wouldn't have happened, then profits wouldn't have enhanced for slave owners. Productivity wouldn't have increased.