The only thing you can do now is a bit of watering and checling the ears again. The grains at the tip will be smaller so peek a little further and put a baggie and rubber band over the opened up ear.

I hope someone pipes in because I have the same problem. I picked 2 off because the kernals came all the way to the top of the ear and the silks were brown, but my corn looked like yours. I left the rest on the stalks to see if they will fill out. My guess is 1) I planted them too close together and waited too long to thin them out 2) It is super dry here and even with the irrigation soakers, they didn't get enough water 3) Not enough nutrients in the soil. They are heavy feeders and I didn't start adding fish emulsion until the corn was already 5 feet.

Were they well pollenated? That can lead to weak filled ears.

In my experience, dented sweet corn kernels is usually an indicator that it is past ripe. What does the row development on the ear look like? (You may have to sacrifice and ear to check.) If the rows are well developed but dented down most of the row then it is past ideal harvest time. Still good, just "starchier" to taste and won't keep as well. Good luck.

Dave

I thought mine weren't "done" enough because while they were indented, they are also very skinny.

Corn is usually ready just over 2 weeks past the time you get silks. The easiest test is when the silks turn brown, open one and puncture a kernel or 2 with your fingernail. If the liquid is clear, it's not ready... if the liquid is milky, it's ready to eat. You may be past the prime time already.

I think the optimal time to fertilize sweetcorn is when it's about knee-high or so, or continuously (slow & steady) with drip fertigation. Corn's a heavy feeder, I don't know if I'd rely just on fish emulsion.

If the ears are full without missing kernels but there are slight gaps between all the kernels, the corn is too old.

I wonder if mine is old or just too dry. I have tried to puncture a kernel but they have virtually no juice to speak of. I am going to go down the row today and see what the other plants look like, i only pulled one cob off yesterday, maybe the other plants are different. All the rows were even but VERY small kernels. The silks at the top were brown but they were still green going into the husks.

SAo I pulled a new one this morning. Kernals are full, white fluid comes out, but the ear out of it's husk is about 5" long. Its a little mini me corn to say the least. I'm ready to pull out the hole crop and toss it into the compost bin. What a waste of time. Well, not a complete waste, I know what NOT to do next time and what to do better.

I have not grown Fleet, it is only recommeded above the 42 parallel. I have grown Quickie which is similar. It is naturally a small very early corn. It is never going to get big ears like mainseason corn. You may also have planted too thick and had insufficient nutrients or you may be too far south for it to perform well.