In every preindustrial farming operation, some of the most important and insurmountable limits to a household’s food supply are imposed by the size and demographic makeup of the work force it can muster to produce it. Apart from the energy for photosynthesis provided by the Sun, the energy for food production in subsistence farming is almost entirely biological in nature – mostly human and secondarily animal (in some places), with wind or water power very occasionally playing a minor role. Almost universally, the labor needed for household food production is organized by the household itself and is indeed made up overwhelmingly of its own members. Granted, as will be discussed in more detail in Chapter 12, voluntary work groups that draw in members of several neighboring households may be mobilized at certain times of year for particularly heavy tasks that need to be done quickly, often in return for some kind of payment in kind (perhaps a part of the harvest, a feast, or a beer-drinking party) or a promise of reciprocation; in addition, individual labor contributions by close relatives living in nearby households may be requested on a day-to-day basis. In this chapter and the next, however, I shall make the model assumption – one of those tactical “lies” discussed in Chapter 1 – that labor on the household farm is provided exclusively by the household itself. I do this to show some of the built-in limitations to household-based food production, limitations that require special social arrangements – the expenditure of “social capital” – if they are to be overcome. The idea that households are wholly on their own when it comes to farm labor may be a tactical lie, but the truth is that most labor in traditional farming is provided by the household that runs the farm (Figure 9.1). The subsistence-oriented household provides by far the largest contribution of nonsolar energy for its own food production.