With the widespread freeze this morning, the growing season is officially over. This morning didn't just see a freeze, though. Most of you saw temperatures fall into the 20s!
The average date for a first freeze in Louisville of the winter season is November 4. A freeze just means the temperature dips to 32º, but a hard freeze is a little different. A hard freeze happens when the temperature drops to 28º, and the average date for that is November 16 in Louisville. So this freeze is a little early, but not the earliest we've ever seen. The earliest freeze in Louisville happened on October 3, 1974, and the earliest hard freeze was October 10, 1964.
What does this mean?
The growing season is over. According to the USDA, "The growing season is defined as that part of the year when soil temperatures at 50 cm (20 inches) below the soil surface are higher than biologic zero (5 degrees C, 41 degrees F)." The end of the growing season means that soil temperature will be dropping below 41ºF. This also means you won't see any more Frost Advisories or Freeze Warnings until plants start growing again in the spring. Practically this means you'll only need to mow the lawn one or two more times this season before the grass stops growing.
