Farm yields and crop quality are closely linked to environmental exposures during growth. Stresses can occur when too much or too little water is delivered. These nuances of farm production are often overlooked by the typical small scale farmer in sub-Saharan Africa. The result is that small scale farms, on average, underproduce by more than forty percent. In this paper, we describe the development of a small scale precision farming approach where fast soil moisture sensing via wireless sensor networks provides a low-cost, low-power option to reduce the potential for water induced plant stresses and increase yields. The solution is particularly suited to resource constrained environments with no access to grid power and poor network connectivity. By monitoring water intake by plants, we demonstrate the potential for fast data collection from wireless soil moisture sensors in the farm. Finally, we show that the developed wireless sensor nodes can run for more than five years with limited human intervention.