Frost tolerant Nasturtiums may survive very light frosts, but they are easily damaged by freezing temperatures.Click to see full answer. Also to know is, how cold can nasturtiums tolerate? 30 to 40 degrees Fahrenheit Additionally, can petunias survive a frost? Effects of Cold on Petunias An outside temperature of 26 degree F or below lasting more than four hours is considered a hard freeze, and this can kill even cold-tolerant plants like petunias. However, they can tolerate frost, and they are planted in September in some warmer climates. Also Know, do nasturtiums come back every year? Although most often grown as annuals, nasturtiums are, botanically, herbaceous perennials; that is, they die to the ground in fall and grow again the next spring. In frost-free areas such as coastal California, they grow like weeds, with 6-inch diameter leaves atop 20-foot-long stems sprawling year-round.Are nasturtiums Hardy?The perennial varieties are mostly winter/cold hardy, whereas the annuals have to be grown each year from seed.As well as being highly ornamental, nasturtium flowers and leaves give a crisp, peppery taste to salads, as well as some great colour.