Wanted: A crop alternative that can handle arid conditions and scorching sun during this current era of mega droughts and rising temperature. An option that tastes great and is nutritious is a major plus.
The answer to this wanted ad need not be new crop varieties or biotech alternatives. The answer may lie with the ancient bean known as the tepary. Tepary beans are known to be among the most arid-adapted crop varieties in the world. They have been grown in the Sonoran desert region, typically without supplemental irrigation, for thousands of years.
HISTORY AND ORIGIN
Tepary beans were domesticated in Northwest Mexico from wild beans that can still be found growing in isolated areas of the Sonoran Desert (see Wild Crop Ancestors). Exactly when they were domesticated is difficult to determine because remains of beans are rare finds in archaeological sites. It was likely around 6-4,000 years ago. One thousand year old archaeological remains of tepary beans are commonly found in ancient Hohokam sites throughout Arizona, including Casa Grande.
For the contemporary O’odham people of Southern Arizona, tepary beans, called Bawĭ, have been central to cuisine and culture for generations. There are many traditional stories about tepary beans including legends that describe how the Milky Way is white tepary beans scattered across the sky. Traditional recipes include variations of tepary bean stews and the dense little beans are hailed as being one of the most filling food gifts from the desert.
COMPARISONS TO OTHER BEANS
Tepary beans (Phaseolus acutifolius) are a different species than other beans and are distinctive in many ways. They are used as a dry bean and are considerably smaller than their cousins the common bean (Phaseolus vulgaris) and lima beans (Phaseolus lunatus). Tepary beans have a characteristic wrinkly skin, although varieties from higher elevations are considerably more plump and round. There is a high degree of diversity including white, tan, yellow, brown, red, pink, black, and speckled or mottled colors and patterns. Color differences do have flavor differences which will be discussed in part 2 of this post. At Native Seeds/SEARCH we conserve nearly 100 accessions of domesticated and wild tepary beans that are adapted to low and high desert environments.
Tepary beans are one of the few crops in the world that have been documented to produce lower yields with increasing amounts of water. They will produce copious amounts of vegetative growth, but lower rates of pod set in overwatered conditions. During periods of water scarcity they are known to produce a yield, although smaller than when ideal conditions are present. No crop will grow without any water or soil moisture reserve. In these types of extremely dry condition most conventional beans will die before producing any yield.
Their ability to grow in hot, arid conditions is the result of several adaptive traits resulting from being grown in hot, arid conditions for millenia. Traditionally they have been dry-farmed in our region that only receives between 2-5 inches of rainfall in the growing season. Temperatures typically exceed 95 degrees here. Other beans are not able to set pods in such extreme temperatures because pollen becomes sterile. They are a short season plant which requires less water over the season. They can produce dry, mature beans in 60 to 120 days. Their leaves are smaller than other bean species and contract with the rising sun to conserve water. Their roots can reach twice as deep as conventional beans allowing them to take advantage of soil moisture reserves.
PLANTING AND HARVESTING
Traditionally, tepary beans are dry farmed and therefore planted after the first soaking rain of the summer monsoon season in early July. They can be planted as late as the first week of August in the low desert. In low desert areas of Arizona where irrigation is available, such as Akimel O’odham territory of the Salt and Gila Rivers of Central Arizona, it is possible to plant two crops – one in the dry spring in March and again with the monsoons. The timing of this planting works well because the rains are absent, around June and early October, when the pods are set and drying in the field. This prevents mold and allows for easier harvest. In areas outside of the Sonoran Desert consult your local agricultural calendar and plant the same timing or even a few weeks later than other dried beans, typically in May or June. Ensure that you have at least 100 days before the first frost date.
Plant seeds at least 1 inch deep, 4-6 inches apart. Rows should be at least 12 inches apart to give them room to bush out. Do not presoak tepary beans. They generally do not tolerate wet conditions and clay soils. Soils that hold some soil moisture is critical, especially if you would like to only rely on the rain. For most varieties their growth habit is classified as a prostrate bush and their branches will lie upon or just above the ground which is why overly moist conditions can be a problem. For small garden areas it is possible to train many varieties to climb a trellis, particularly high elevation and wild varieties.
When the pods begin to dry out you can stop giving supplemental water. Harvest the entire plant by pulling it out or cutting at the ground surface when about 75-85% of the pods are dry. If you have a small plot of tepary beans you can pick individual pods as they become dry. Pile plants up on a tarp or sheet for a couple weeks to allow the remaining pods to dry. The pods of tepary beans shatter easily which is one reason more widespread commercial adoption using mechanical means has been slow to catch on. They will begin to pop open on their own and a little stomping or hitting with a rake will loosen the remaining beans. The beans will sink to the bottom of the tarp. Rake away stems and leaves for your compost. The remaining beans should be winnowed to remove any remaining chaff and dirt. Use the wind or pour beans in front of a low fan. Seed screens or colanders work well.
Ensure that the beans are fully dry before putting them up for storage. Storing in high moisture conditions could cause them to mold. The high moisture will also lead to longer cooking times.
Part 2 of this series on tepary beans will cover cooking instructions in more detail and provide nutritional information as well as recipes. In general, tepary beans require longer cooking times than other beans. Even though they are smaller, they are denser. Soak clean beans overnight and drain. Cover with water and cook in a slow cooker for 6-8 hours or on the stove top for 1 ½ to 3 hours.