University of Missouri Extension’s Frost/Freeze Probabilities Guide tells us that it’s time to think about protecting plants from frost, said MU Extension state horticulture specialist David Trinklein.
Although near-freezing temperatures are not currently in the forecast, daily temperature normals are dropping and daylight is dwindling, says MU Extension state climatologist Zachary Leasor.
The median dates of frost-freeze probabilities vary by region in Missouri. Based on historical data, northern counties would experience their first frost around Oct. 11. Central Missourians usually see the first freeze around Oct. 20, while the first freeze is around Nov. 1 in the southern part of the state. Frosts are more likely to come earlier over the Ozarks compared to central Missouri due to the Ozarks’ higher elevation.
Not all plants react the same to lower temperatures, Trinklein said. “Certain species, especially tropical ones, suffer ‘chill injury’ at temperatures well above freezing. Most species in this category should not be exposed to temperatures lower than 45 degrees Fahrenheit.”