In wet rice agriculture, seeds are sown in small seedbeds; the seedlings are then transplanted one by one to prepared paddy fields. While the plants are maturing, they must be kept irrigated, but as the rice ripens the fields are drained. The rice is then harvested and threshed by hand. Wet rice agriculture is labor-intensive, meaning that many people are required to do the job (as in the cultivation of silk worms and tea). Labor is particularly important when the fields are prepared, seedlings transplanted, and again when the rice is harvested. At these times, increasing the number of people working can significantly increase the amount each field can produce. In some areas a farmer can increase productivity by double or triple cropping (2 or 3 crops of rice) each year, a technique that requires even greater concentrations of labor because the harvesting of one crop and the transplanting of the next crop occur virtually simultaneously. At other times during the winter or while the rice is maturing, the demand for labor is greatly diminished. Traditionally, Chinese farmers, with their families as their labor force, put everyone to work in the field when labor was needed. During slack periods women and younger children could do other work for the family, including handicraft production.

Traditional agricultural methods and population growth are thus closely related. As the amount produced increased, population increased. As population increased, the added labor led to increased production. The more workers available to help in the field the more rice one field could produce, so it was to a family's advantage to have many sons (since daughters married out of the family, they generally were not considered assets). High infant mortality and the reliance of aged parents on their children for support reinforced the ideal of the large family. At the same time, the larger the family, the more rice the farm had to produce in order to feed them. Consequently, the best chance a Chinese peasant had to improve his life was to have a large family, intensify the family effort to cultivate rice, then use whatever extra income they were able to produce to buy more land until he owned just as much land as the whole family, working together, could farm at maximum productivity. In some cases, even more land might be purchased for rental to tenants.