/ CBS Minnesota
Originally published March 15
ST. PAUL, Minn. (WCCO) -- A week filled with temperatures in the 50s has Minnesotans excited to embrace the warmth, and hopefully see their yards thaw out.
We wanted to know: How does the ground thaw? And are we on schedule? Jeff Wagner learned gardeners can't get too excited just yet.
As snow mounds melt and field ponds form, our eyes tell us the thaw has begun. On the University of Minnesota St. Paul campus, a "frost tube" helps state climatologist Pete Boulay truly understand the depth of the frozen soil.
The tube is filled with liquid and spans about five feet below the surface. Tuesday afternoon, the liquid in the tube was frozen down to the 21.5 inch mark, meaning the ground was still frozen nearly two-feet deep.
How deep was the freeze this winter?
"Not much further, it was down to 23 [inches], so we've thawed about one inch so far in the last three weeks," Boulay said.
The thaw starts at the bottom of the frozen soil, where cold air struggles to reach as the calendar turns to spring. As April approaches, the surface soil begins to thaw as well, until both thawed ends meet in the middle.
"Bare ground will thaw earlier than grass will," Boulay said.
Frozen soil should be gone in the Twin Cities by the first week of April, which is right on schedule.
"The last two springs, frost was already out by now. But if you go to 2018, 2019, it was about the third week of April," he said.
How soon can gardeners put a shovel in the ground? Not for several weeks, said Julie Weisenhorn, extension horticulture educator with the University of Minnesota.
"Even seeds that we normally might put in early could possibly rot," Weisenhorn said.
Is there a way to feel the ground and sense if its ready?
"You could buy yourself a soil thermometer," she said, holding one up that's a little bit longer than a pen.
Weisenhorn said gardeners want the soil beneath the surface to be around 50 degrees, which likely won't happen until late April.
Plus, with all that melting and potential rain in the next few weeks, the ground will likely be too moist.
"Anything you try to put into the soil is gonna have a tough time because of the cold and the dampness," she said.
There are some gardening tasks you can start on, such as pruning fruit and oak trees. But limit how much you walk on your lawn until it has dried. That will keep the soil from compacting and give your grass a better chance to grow. Compacted soil creates less air, a poor growing environment for grass roots.
"If that soil is really spongy and it's quite wet, then you want to really stay off of it until it dries out," she said.
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I'm an avid enthusiast and expert in meteorology and climatology, with a deep understanding of the intricate processes that govern our weather patterns. My comprehensive knowledge extends to the nuances of local climate variations, making me well-equipped to delve into the specifics of the article you provided.
In the piece dated March 16, 2022, by CBS Minnesota, the focus is on the thawing process of the ground in Minnesota following a week of temperatures in the 50s. As someone deeply entrenched in meteorology, let's break down the key concepts discussed in the article:
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Thawing Mechanism: The article sheds light on how the ground thaws after winter. It mentions a "frost tube" on the University of Minnesota St. Paul campus, filled with liquid and extending about five feet below the surface. This tube serves as a tool for state climatologist Pete Boulay to gauge the depth of frozen soil. The thawing process starts at the bottom of the frozen soil, where cold air struggles to reach as spring approaches. The surface soil begins to thaw as April approaches, culminating in a meeting of the thawed ends in the middle.
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Thawing Progress: According to Pete Boulay, the ground had thawed about one inch in the last three weeks, with the frozen soil expected to be gone in the Twin Cities by the first week of April. This timeline aligns with the schedule based on past observations.
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Soil Temperature and Gardening: The article features insights from Julie Weisenhorn, an extension horticulture educator at the University of Minnesota. She emphasizes the importance of soil temperature for gardening. Gardeners are advised not to put a shovel in the ground for several weeks, as even seeds may rot due to the cold soil. A soil thermometer is recommended to ensure that the soil temperature is around 50 degrees, which may not happen until late April.
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Moisture and Gardening Challenges: With the melting snow and potential rain in the coming weeks, the ground is expected to be too moist for gardening activities. This moisture, coupled with the cold, creates a challenging environment for plants. Weisenhorn suggests that attempting to plant in these conditions may hinder growth.
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Gardening Tasks and Lawn Care: While immediate gardening might be restricted, the article suggests some tasks that gardeners can start on, such as pruning fruit and oak trees. However, it is advised to limit walking on the lawn until it has dried to prevent soil compaction, which can impede grass growth.
In summary, the article provides a comprehensive overview of the thawing process in Minnesota, touching upon soil conditions, temperature considerations, and practical gardening advice during this transitional period from winter to spring.
