How Long is a Piece of String?
That’s the answer to how long it takes for corn to emerge; in other words, it depends.
There are many considerations influencing corn emergence; soil temperature, soil type, environment, weather, wet/dry conditions, crusting, etc. However, typically, corn requires from 100 to 125 growing degree days (GDD) to emerge.
Under ideal conditions with warm soils, emergence can occur in a few as 5 to 10 days after planting. In cold conditions, emergence can take up to four weeks. Corn must absorb 30% of its weight in water to germinate. Growth occurs at soil temperatures of 50ºF or higher.