PREHISTORIC AGRICULTURE:
GRID AND WAFFLE GARDENS OF THE U.S. SOUTHWEST
by Tom Baker
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It is not surprising that archaeologists show great interest in early forms of farming, since the adoption of agriculture by prehistoric peoples as their main source of food is viewed as a prerequisite to true civilization worldwide.
When buzzing about in remote areas of the U.S. Southwest in an airplane, it is not unusual to encounter traces of prehistoric agriculture on the landscape below that are usually referred to as "grid gardens" or "waffle gardens," so named because they often appear as either gridded lines on the ground or areas of contiguous squares reminiscent of a breakfast waffle ("prehistoric" in this area means prior to Spanish contact in 1541). Often the lines on the ground are formed by stones that prehistoric farmers apparently gathered and used to outline or surround their rectangular growing plots or gardens. In the case of waffle gardens, the squares may be the remains of low clay or adobe walls rather than rockpiles or alignments, although in the aerial photos above they appear to be stone borders. As the accompanying aerial photos show, these garden plots are anything but standard in size, and in fact can appear in a wide variety of shapes and sizes. As some of our photos illustrate, the lines can also be curved, sometimes almost into circles, apparently done when necessary to conform to the lay of the land. It is noteworthy that prehistoric gardens often appear in sandy plots, possibly because sand holds moisture well, and although straight alignments were obviously preferred, the stone or adobe lines will sometimes curve or curl around the edges of a sand formation or dune.
This is a type of agriculture called "dry farming" because it did not employ irrigation from constantly flowing streams or rivers, which are rare in the deserts of the Southwest. Instead, the prehistoric Indians depended on rainwater for their crops, which in this arid country is relatively scarce and had to be collected and hoarded assiduously. Irrigation farming was not unknown before the arrival of Europeans, as shown by the many miles of irrigation canals in certain areas of Arizona, which were built by a vanished people known as the Hohokam. However, from the evidence visible to the aerial archaeologist today, the Anasazi Indians of New Mexico and southern Colorado appear to have preferred dry farming on hillsides and mesas away from the few flowing rivers for some reason. Of course, it could be that some form of irrigation farming was carried out in river bottoms at the same time as the dry farming on surrounding hills, and the evidence in the river bottoms has perhaps been washed away by centuries of flooding, but at least we can say from an aerial point of view that the Anasazi left no traces of extensive canals such as the Hohokam built.
Although I have not kept myself up-to-date on research into this subject, to my knowledge no one has been able to figure out exactly how prehistoric grid or waffle worked, although informative experiments have been conducted and I have heard a lot of educated guessing over the years. One theory is that the stones or clay walls surrounding the little square or rectangular garden plots absorbed the heat of the sun and thus warmed the nearby ground, while at the same time the sand or gravel they contained helped hold moisture. In this scheme, warm rocks (especially black igneous ones, which like anything black can get scorchingly hot in the desert sun) carrying the heat of the day on into the cool of the evening would have been a way of extending the short desert growing season a bit. Archaeologists digging in grid gardens have found gravel that was apparently deliberately dumped into the plots, so that some prefer to call them as "gravel-mulch gardens." The tight clay walls surrounding waffle gardens would have also held moisture around the plants within each square.
When flying over the Hopi Indian villages of Arizona we have photographed garden plots adjacent to the pueblo villages that look remarkably like some ancient ones. Likewise the Rio Grande pueblos often have small rectangular garden plots around the towns. In historic times, observers recorded that the Pueblo Indians carried water in pots or jars from some source such as a well, spring, or cistern to each individual plant in their gardens, a tedious but effective way to water the crops between rainstorms.
We have photographed artificial lines of stones in usually dry gulches (arroyos or wadis) that, as in all deserts, can become roaring torrents during the violent thunderstorms so common in this climate. In this case the stone lines probably represent dams built by the ancients to slow the rushing water down, promoting absorption into surrounding soils, trapping and collecting fertile sediment to form new garden plots, and may have also diverted the runoff toward nearby established gardens. In some areas we have also photographed small piles of stones set out at regular intervals over wide areas of ground, forming interesting patterns. In that case we may be seeing either the incomplete makings of grid gardens, that is, stones that were gathered by people who intended to create grid gardens with them but never completed the task, or the piles may have some unknown function of their own. Someone suggested that they may have served to slow sheetwash runoff on hillsides during rains.
Whatever you choose to call these ancient garden plots, and however they functioned, one thing is certain, and that is that growing food plants in small bordered garden plots was probably about as efficient as rainwater farming could be in Stone Age Southwestern North America. It may still be an effective way to grow small crops today in areas where stream irrigation is impractical. In fact, as any aerial observer can testify, the ancient grid or waffle gardens, abandoned so many centuries ago, still function today, although their "crops" may now be only the natural vegetation of the desert rather than the corn, beans, or squash planted by the prehistoric farmers. In an aerial view of the landscape, grid gardens are the first things to "green up" in the spring, and the last to fade to brown in the fall, showing that, however they work, they work still.
Tom Baker
Footnote: the six aerial photos above show only some common forms of prehistoric grid and waffle gardens, in this case all from a single area in central New Mexico where they appear extensively (in fact they cover many square miles of the landscape there). They are simply offered as examples of Anasazi food gardens. Drawing from a file of aerial photos taken over decades, we could provide many more illustrations of prehistoric Southwestern agriculture, some of it not bounded by stone or soil alignments at all and only clearly visible in infrared photography. We will expand this section of the website if enough interest is shown--please contact us if you'd like to see more. Researchers into this type (or related forms) of ancient agriculture are also invited to send us information which we will publish here for the interested public. Non-experts are invited to simply speculate on the origins and uses of grid and waffle gardens--sometimes casual observers provide the best insights of all.