I don’t want to grow it outside.
First things first, you’re going to need a bigger barn.
After you get a bigger barn, remove the roof, or install at least two gro-bulbs. You’ll need an elephant to tell when the corn is done growing.
You could just plant popcorn, that grows well inside. And some varieties come in ready-to-use li’l bags that say “This Side Down” to make it easier to know where to sit.
Since it would be a barn, ( hopefully a very large barn ) You could take the roof off and just make it a sun roof or you could use that white nylon screen in place of the roof so when it rains, the water will get through and when it’s blazing hot you’ll have some protection from the sun.
First, plant it in a greenhouse. Then, roll up your greensleeves and get to work!
Corn has a seriously long tap root, so you’ll also need to get rid of the base that is probably there in your barn already. You should remove it to at least 2 foot deep and replace it with high nitrogen soil.
Look at hoop houses for a more realistic idea.