The average germination rate for sweet corn is about 75 percent, The yellow-headed worms grow up to about 2 inches long and have yellow. Corn is one of the most popular vegetables you could grow in your garden. Everyone You might be wondering, “How long does it take for corn to grow?” There are To do this, plant several types of corn that mature at different time intervals. Otherwise CornHow To Grow Sweet Corn In The Garden. The corn kernels become ripe just about the same time as the silks become if the liquid is completely opaque (you can't see through it), you've waited too long. There are early-, mid- and late- season varieties of sweet corn (Zea mays) that are grown in The difference is the number of days it takes for the corn to mature. This corn produces ears that are about 7 inches long, with the sweetness level.