March 20 marks the start of spring, but even before then, the fluctuations between continued winter weather and doses of unseasonably warm weather could lead to a sense of “false spring.” And while that may lead to mild disappointment among residents of Northeast Ohio, eager to bask in more temperate weather, it could have serious consequences for native plants.
False spring happens when winter is interrupted by a period of warmer temperatures, according to Frank Becker, an educator in agriculture and natural resources with The Ohio State University extension in Wayne County. This can give the illusion that spring has finally arrived, only to be shattered when colder weather returns. False spring, Becker said, can pose a threat to perennials and some crops.
“If we have that for too long or too significant of a time, or even too warm of a temperature, then it can cause a little bit of a concern with plants coming out of dormancy,” he said.
So far, Becker said the region has not warmed for a long enough stretch for a false spring to endanger plants.
Plants become dormant in the winter to protect themselves from the cold, according to Becker. They rely on cues from both sunlight and temperature on when to start growing again.
While many plants in Ohio, he said, have a tolerance to limited frost exposure, a plant’s ability to survive an extended stretch of colder tempearatures following a false spring depends several factors.
“A lot of the plants that, especially when we think about trees, something that's woody, it's well-established, it would take several years of that kind of situation to really cause plant death,” Becker said. “Now on the other side of that, when you think about some of your more herbaceous perennials, it doesn't necessarily take a lot.”
Some crops, like peaches, plums, nectarines, and apricots, are more susceptible to damage, Becker said.
The false spring in mid-February didn't pose much of a risk since the overnight temperatures still usually remain below the 50-degree threshold, Becker said.
"If our daytime high was only like 52, but our nighttime low stayed well below 50, basically you would have no heat unit accumulations those days,” he said. “The concern would be, you know, having warm daytime highs as well as warm nighttime lows.”
Ultimately, Becker warns home gardeners not to let a false spring lull them into a false sense of security about getting an early start on getting plants and even seeds in the ground.
“Until our ground temperatures are really consistently above 50 degrees,” Becker said, “ ... with cool wet soil conditions it really is conducive to loss of seeds, just through rot or, if you're putting plants in the ground, they're just not really going to get the jump start they need with good soil conditions.”
If you're still planning on planting, the OSU extension's gardening calendar advises waiting until the dangers of a last frost have passed, typically the beginning of May.
