The Construction and Configuration of Anasazi Pebble-Mulch Gardens in the Northern Rio Grande

Abstract

Rio Grande Anasazi in the fourteenth and fifteenth centuries A.D. mulched hundreds of garden-sized plots with pebbles to increase soil moisture, reduce erosion, extend the growing season, and increase crop yields. This paper reports on the construction and configuration of pebble-mulch gardens in New Mexico, focusing particularly on those in the Galisteo Basin. Surfaces adjacent to these gardens were scraped and pits were excavated to collect gravel, which was placed over garden surfaces in layers 5 to 11 cm thick. Gardens averaged 15 x 23 m in size, although both size and shape were highly variable, and they collectively covered an area of 41,000 m 2 Although this unique agricultural strategy has been shown to be effective, construction was limited to sites with natural gravel deposits, pebbled surfaces inhibited the recycling of crop wastes, and such gardens never became as widely used as more traditional field forms.