Your corn may be approaching tasseling. More likely it's waist-high or better and at the 10th to 12th leaf stage, growing "like a weed." For some, it may still be at a younger stage, but growing points should be above the ground.
If you take a 9 to 10 leaf plant and look from the top into the whorl, you can see the leaves left to come out. The growing point is in charge of the plant.
Dave Nanda, Director of Genetics and Technology for Seed Consultants, Inc., says the tassel is wrapped up inside and is at the growing point level. If you split the stalk and look inside now, you should be able to find evidence of a miniature tassel. When it's finally emerged the reproductive stage begins.
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Corn is in the rapid growth phase right now. If hail or high winds damage the crop, especially hail, it may impact the growing point and the tassel. Corn is most vulnerable to yield loss from hail if foliage is removed at tasseling stage, compared to any other time in the plant's life. That's based on a chart from the National Insurance Association. You can find the chart in the Purdue University Corn & Soybean Field Guide, either in the pocket edition or in the smartphone app.
The value of splitting a stalk or two open at this point is to learn more about how the plant develops. Then when you find a situation that isn't normal, you will be able to recognize it. This may help identify spots where something has gone wrong, and point you toward possible causes and solutions. Sometimes it's something you can address this year. Many times by this point it is something you can assess and make changes in your production program for next year.