Itâ??s hard to believe with temperatures in the 90â??s just a few weeks ago that parts of the Heartland could be experiencing a frost come this weekend. A grim outlook for many summer plants, but there are some things you can do to protect your plants.
Experts recommend covering vulnerable plants with sheets or row covers. You can also use a five gallon bucket by placing it directly over the plant. While these will help protect plants in the ground, non native and potted plants need to have more aggressive action taken.
â??The potted plants are often more at risk then the ones in the ground because they have limited root volume in the pot that they are in. We do recommend that people bring in any kind of potted plant, especially tropicalâ??s. Tropical plants tend to even get damaged in the middle 30â??s. When temperatures get below 40 degrees a lot of those tropical plants really should be moved into a garage or into the house,â?? University of Missouri Horticulture Specialist Jennifer Schutter.
Typically heading into the fall even a light frost will destroy more tender summer crops such as tomatoes, peppers and annuals leaving many with dead blackened plants. But for hardier fall crops and plants, a light frost wonâ??t do severe damage.
â??Cool season plants such as the broccoli, turnips and even cauliflower. A lot of the fall plants will withstand a frost. They generally wonâ??t be killed until temperatures get down around 25 degrees. I have seen pansies even, a nice fall flower, grow through the snow,â?? said Schutter.
Now getting a frost in September is a few weeks early for the Heartland, but not unheard of. Climate data shows across southeast Iowa the first frost occurs in early October while areas near Macon experience their first frost towards the end of October. The average first freeze or killing frost, for Kirksville is around October 10.
For all but the tenderest plants, it doesnâ??t matter whether conditions produce a frost or a freeze. Whatâ??s important is how cold it got and for how long. When temperatures near the freezing mark, a few degrees can make a big difference.
Temperatures from 28 to 32 degrees usually only harm very tender plants with frost forming on the outside of plants. If the temperature falls from 25 to 28 degrees, it is considered a killing frost or freeze and only the hardiest plants survive. The inside cells of the plant will form ice, causing it to burst. At temperatures less than 25 degrees, the growing season end for all seasonal plants.