Whether you’re in the arid Desert Southwest or in the temperate regions of Europe, summers can get hot, the rainfall a little more sporadic, and even the most tolerant plants can begin to struggle. Fortunately, there’s a simple, time-tested solution that’s making a comeback: ollas. Used for thousands of years, this low-tech method relies on unglazed terracotta pots buried in the soil to deliver water directly to plant roots. By creating a steady, subsurface source of moisture, ollas help regulate soil conditions, reduce evaporation, and discourage weed growth....