The corn is planted about one inch below the surface, and usually germinates in about six days. The places where corn does not grow should be replanted to ensure six plants per tub. Corn is nitrogen hungry and usually kept on grow nutrient until after the top has tasseled and the silk has formed. When the corn tassels, the pollen has to fall from above onto the leaves below and into the fold of the leaf. If all the silk is pollinated the corn kernels should all form.
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.