oh- and they are pretty close together that's also why i just left the pollination to nature. i have 3 rows of corn with 6 stalks in each row. each stalk is about a foot away from another. any ideas?

Phil is right on. Being an old farm boy, I know a bit about corn growing and perfect weather during pollination adds greatly to yields. A poor "stand" (plants too few and far between) also greatly impact production. We had a very heavy rain right at peak pollination time this year and some of my ears had "blank spots", an area where no kernels were produced. This is caused by poor pollination. (It also can be caused by over zealous gardeners opening up the tip of the ear to check to see if the corn is getting ripe. ) Ears which show good kernel development at the base but have a tip which is blank or is not filled out have suffered from lack of moisture/excessive heat when the ear is filling.
By the way, unless you are doing it for fun, it is a waste of time to grow sweetcorn in a small garden. The very nature of the crop requires a larger area. Four 25' rows of corn about 24-36" apart with plants about 6-8" apart is a good place to start. Go bigger from there. If you ever look closely at huge fields of sweetcorn or regular fieldcorn, you will notice that the outside rows and end rows are seldom as productive as inside rows. Moisture and poorer pollination are some reasons are well as soil compaction.