Almost all corns will cross pollinate if they not either seperated by distance or time. Back when we grew a lot of sweetcorn we would talk to the farmer of the field corn bordering on our ground about it's days to pollination then plant ours to they did not match. That's probably what you will want to do with your plantings. The Midwest Vegetable Production Guide for Commercial Growers has a section talking about isolation as well as some recomendations so you might want to take a look at it. The link is below.

Although we do not grow much corn anymore (there is a massive sweet corn only operation that attends our markets and has a stellar reputation) we really like Obsession. It's a bicolor 79 day SH2 that tastes great and holds really well. Incredible is also a good yellow corn. Back in the day we planted almost exclusively Illini Super Sweet. I know there are some new developments along that line but do not know much about them. It does have good name recognition which can help with marketing.

Tom

Here is a link that might be useful: Midwest Com Growers Handbook 2013

Thanks for the link. A LOT of info on all the vegetable types.
I think I understand the relationships required, and it looks like 14 days +/- from pollen shed start on one variety until pollen shed begins on another variety is safe.
So, IF maturity dates are an indication as to when pollen shed begins and reasonably equal across all varieties (a lot of ifs) then my early variety and my field corn should be OK if planted on the same date (Early Sunglow 66 days to maturity and Hickory King White Dent 89 days to maturity).
What I need is a full season variety to fit between the two. However, only 23 days to work with....
Out of curiousity, What happens when 2 sweet corn types of the same color (white), and also of the same type (say, SU or SE), but one is early and one is late season, cross pollinate?
I'm not interested in producing seed so how will the difference in the two varieties show themselves? I mean, they are both sweet corn and they are both white, so what's the problem if they cross?
I'm also thinking I might be able to plant early corn and dent corn at same time then wait a couple of weeks and plant another sweet corn with similar maturity date to Hickory King..... say "How sweet it is" at 85 days.
Any ideas?

If they are the same type then nothing happens if they pollinate together. If they are different types it may happen that some of the kernels are not sweet enough. The neighbor field's sh2 corn pollinated at the same time as my way too early triplesweet corn and it was just ok to eat, not that sweet. The next ears to mature were super sweet when not crossed.

Both of your corns are su or standard. You can add se without isolation. Only sh2 causes a problem for su and se. I prefer se corn such as Ambrosia. The field corn will have to pollinate quite at a different time from the sweet.

littleminnie- when you say the field corn will have to pollinate quite at a different time than the sweet", I'm taking it that you mean that even if the field corn is an SU type (like my sweet corn) that it WILL still be a problem if they cross pollinate?
Thanks for the info on the ambrosia. So, looks like I can plant that and not have to worry about crossing with my SU type.... however, still need to worry about crossing with my field corn..... correct?

My personal favorite is Seredipity, but haven't grown much myself. I make sure that the surrounding farmers are planting beans that year. I'm surrounded by big farmers.

I've tried many different varieties over the years. Serendipity is indeed good, but my the most reliably good corn for me has been Bodacious. It is sweet, a reliable producer,has a tight wrap, and fills to the tip.

I was only giving my 'tasting' experience. Don't know anything else, but taste buds.

Filling to the tips are sometimes an indicator of how much Boron you have in your soil. The seed people are actually experimenting with adding boron in the corn seed. On our farm, we don't need any at all, not toxic as long as we don't add any for a few years.

I believe that is correct emyers.