Tuesday is the first day farmers in South Dakota can plant and still be covered by crop insurance if that crop is damaged by frost. In Minnesota, that day is Wednesday. Yet despite the cool weather looming in our forecast, farmers expect to be hitting their fields early Tuesday.
Temperatures will largely dip below freezing the next two nights. With dry weather in all but the farthest west counties, the topsoil is dry. Since moisture is lacking, ice crystals forming underground should not be the major concern with newly planted seed buried deep. But dry ground also heats and cools quicker than moist ground, so we're more likely to get colder farther down, if only briefly.
With some gardens already planted and shoots sprouting, the exposed parts aren't protected by soil. In Iowa, the soil temperature varies a lot from the middle 40s to near 60. That mirrors the air temperature.
Our climate suggests frozen soil through April so cold is not unusual. What isn't typical is how fast plants shot up and that could harm them with the cold snap.