Microbes limit risk by stochastic bet hedging - low frequency expression of cells constitutively preadapted to many stresses including antibiotics/ By contrast, here we report continuous variation in the induced frequency of cells with slow osmotic stress signaling, survival and proliferation among 50 ecologically-distinct strains of budding yeast challenged by sudden hyperosmotic stress. Despite extensive variation in early mortality, strains displayed robust perfect adaptation and recovery of steady-state viability in moderate stress. In severe stress survival depended on strain-specific proportions of cells with divergent strategies. Cautious cells survived without dividing; reckless cells attempted to divide too soon and failed, killing both mother and daughter. We show that heritable frequencies of cautious and reckless cells produce a rapidly diversifying template for microbial bet hedging that mimics natural variation in stress responses whose timing, amplitude and frequency could evolve -be tuned by- different patterns of environmental stress.