Corn likes a high nitrogen fert and I've used blood meal for side dressing once the corn is knee high with good results. Some recommend using a lawn fert which are typically high nitrogen formulas but be careful not to use lawn ferts that contain weed killers. If I made my own corn fert mix it would be in the 20-5-5 range as a side dressing. I'd let your new corn transplants adapt to their new ground for 10 days before applying any fert.

Agree. Corn is a heavy nitrogen user, one of the BIG nitrogen users in the garden. And at least two staged feeds of a high nitrogen fertilizer is necessary unless your soil is already very high in N. Otherwise feed heavily at 12-18".

Neither of the fertilizers you have will be sufficient.

Dave

I always side dress with sodium nitrate when it is about knee high and have good results.

The classic regimen for corn as I learned it was 13-13-13 tilled in the furrow prior to planting and sidedress ammonium nitrate (34-0-0) at knee high with a hilling at that time and again at waist high.
The second could be skipped if the leaves don't show a need for it. Corn will show a need for nitrogen in it's leaf color, should be a nice medium tending to dark green of an even color.