This chapter discusses the Preceramic plant-use history of the Zaña, Jequetepeque, and Nanchoc valleys. The long-term accumulation of water flotation data throughout the valleys from El Palto, Las Pircas, Tierra Blanca, and terminal Preceramic phase sites has produced a fine-grained plant-use record that may be set against the culture history as produced by more traditional datasets. During the early Preceramic El Palto phase (11500–9800 bp), highly mobile groups used plants as reliable supplements to their hunting lifeways, with a strong coastal focus on algarrobo pods, cactus fruits, snails, and other wild foods. In the upper valley, the cultivation of squash began during this phase. The Las Pircas phase (9800–7800 bp) was a time of continued broad-spectrum plant collecting in much of the valley but also the local development of multiple plant cultivation and house gardening in selected areas such as the south bank of the Nanchoc River. Simple feeder ditch technologies may have begun during this time as well (Dillehay et al. 2005). The cultivated plant inventory increased toward the late Las Pircas phase (8500–7800 bp).

During the following Tierra Blanca phase (7800–5000 bp), the intensity and nature of plant cultivation changed, with a shift from single-family house gardening to multifamily fields and canal systems (Chapters 6,11,12). Plant use during the Preceramic phases is understood in terms of persistent hunting-gathering in much of the valley, plus a gradual adoption and proliferation of house gardening and then irrigation technology applied to community agricultural fields in the upper valley.