UpdatedThu, Apr 29, 2021 at 1:32 pm ET Reply Outdoor spring planting of corn, green beans, turnips, potatoes, spinach and other popular crops should start after the final frost date, as the Old Farmer's Almanac says tender plants can be killed when temperatures dip below 32 degrees Fahrenheit. (Shutterstock) ACROSS AMERICA — The right time to start planting seeds outside varies by year, and even more so by region. But an Old Farmer's Almanac tool can help gardeners across all 50 states plan ahead by finding the typical date of the final spring frost. There's a 30 percent probability of frost occurring after the spring date listed, as the date is determined using National Oceanic and Atmospheric historical data from 1981-2010 and is not "set in stone," the Old Farmer's Almanac said.