Corn pollinates the silk coming out of the corn from the tassels at the top of the plant. Ears of corn that are not fully filled out is a result of not enough pollination. Planting several short rows is better than one or two long rows. This will ensure proper pollination. In a very small garden you can take a tassel and go around tapping some of the pollen on each of the silks to increase the chances of pollination.
Corn can grow very tall in hydroponic culture.
Expect the corn to grow to seven feet tall. In hydroponics the corn is often a smaller percentage. There is a loss of nutrient in this process. However, corn stalks make a viable paper product and can be used to wrap food. They are also excellent in composting.