I look at the corn every few days; grab an ear from each of the three fields and look to see how they're progressing. The little bit of unpollinated corn at the very tip tells me that I've got my population a little too low -- I probably could have planted a little closer together, but overall the corn looks good. The three fields are similar; the one on the left is the top field, the right is the bottom field. The middle field is the largest of the three.
I'm looking for a milk line in the kernels to measure the progress towards being ripe. The milk line is present in these kernels; you can see it as a whiter area of each corn kernel. that line will progress until the whole kernel is the same color, and then as the kernel dries it'll form a little dent in the end, hence the common term for this sort of corn: dent corn.
Having looked at the cobs, I toss them to a waiting pig; the pigs like it a little bit sweet, so a little milky and unripe is just what they like the best. this pig stands on it to make it easier to bite the kernels off, and is oinking with pleasure when she does this. They also eat the green husk leaves. A little salad with the main course.
Most of the corn plants have 2 ears on them; some have 3. This is the first time I've grown commercial quanties of corn, so it's a little nerve racking for me; lots of things can still go wrong.