As I descended from higher elevations, there were some irrigated patches of farmland surrounded by desert. Triple Farms in the Mohave Valley beckoned with a farm stand. At the edge of their parking area, pomegranates were growing out of straw bales.
Their chickens seemed to have no trouble walking on straw bales. There was a large inventory of bales out back. Straw covered many of the pathways. And loads of produce was growing out of bales.
Straw bale gardening does not strike me as particularly sustainable, since it generally requires bringing in lots of inputs. To make farming more sustainable, one priority is to reduce off-farm inputs such as fertilizer, water, and growing media. However, there are many farming challenges for which straw bales provide a practical solution. In an urban environment with toxic soils or straight pavement, nothing beats plunking down a bale of straw to let you get started immediately. For back-yard gardeners whose arthritis prevents them from bending over or those who are confined to a wheelchair, straw bales provide an inexpensive alternative to building raised beds. To extend the growing season for a few plants, a greenhouse would be overkill. Perhaps a straw bale or two could do the trick. And then there's the desert and the beach. The soil may be so lacking in organic matter that it needs massive fortification. Straw bales can get you growing right away, if your soil conditions are inadequate.
That said, I would have liked to ask the knowledgeable farmworkers at Triple Farms about the pros and cons of their straw bale strategy. There were helpful farm-stand workers who were happy to answer questions about the diversity of produce for sale, but, alas, all the farmers were out of town.
Nonetheless, I will push forward with something of a thought experiment based upon my observations, in lieu of an actual interview. If you think I am a bit presumptuous, I wouldn't blame you. I imagine that a large quantity of water is necessary to grow anything here, especially for plants growing in straw, a growing medium that does not hold water particularly well. It did not appear that all the plants were growing in straw bales. Some were growing in depressed planting beds - a water conserving strategy. With depressed beds, all irrigation water drains toward the plants.
I also noticed some horses kept beyond the vegetable plots, so Triple Farms may be using straw bales as growing containers and composted manure (or manure tea) as fertilizer. As summer wears on, the straw will continue to decompose into lovely compost that may be spread over the rows or further composted, adding nutrients to the soil. In an area with poor soils, this may be a more sustainable practice than carting in a similar quantity of topsoil from far away. And lastly, the folks at Triple Farms are looking out for the health of their customers, growing chemical-free produce.
Unlike most places in the United States where summer is prime growing season, summer in the Mohave Valley takes its toll on vegetables. It just gets too hot. The farm stand is now closed.