I am planting corn for the first time this year. I have some Kandy Corn (se) and my neighbor is planting Merit. Our corn is going to be withing 20 yards of each other because he is letting me use some of his space for my corn. Will his Merit affect the taste of my (se) Kandy Corn? I will will not/cannot save the seeds so that is not a concern. I just want to make sure the sweetness of my corn is not going to be hindered and if so, I will have to adjust my planting. Thanks for the responses.
Yes, they will cross. They have similar maturities so staggered planting is the only way to prevent it. Merit is not as sweet as Kandy Korn, but unless your taste buds are very sensitive, you probably would not notice any crossing. Otherwise they are similar in growth and appearance of ears.
Even in Zone 7, you're not planting corn yet. Since you've got time to plan and since seeds are relatively cheap, I'd suggest you get with your neighbor and arrange to plant the same variety of sweet corn, whatever it is. It seems like possible cross-pollination problems could be easily avoided by both of you, at this stage.
I grew Kandy Korn for years and we liked it a lot, but I switched to other (se) varieties because Kandy Korn stalks are so BIG. My Kandy Korn always grew 8+ feet tall, and I found the ears would get stunted if I planted it closer than 42" between rows and 14" between plants in the rows.
There are other varieties, Delectable for one, that grow ears just as big and sweet but on 6' stalks that can be planted 9" apart in rows 36" apart. That lets me raise a lot more corn on the same amount of ground.
Since Kandy Korn is se (or Sugary Extender) it DOES NOT need any isolation from other se or su corn. It DOES need isolation from sh2 and sy corn or it could become "startchy". I'm not familiar with what type of corn that Merit is but you can ask your neighbor and use the guide I gave you.
Also remember that isolation isn't ONLY by distance but you can plant your corn to tassle two weeks before or after your neighbors.