I am having a little trouble with some corn stalks I have begun. The first problem, is that I think I did not place them deep enough in the soil to germinate properly. So that may or may not be a nonissue. What I am actually concerned about is that they have begun developing a light brown discoloration on the top portion of the leaves. I am posting a photo in hopes that you can help explain what that is and how I can fix it. Any help is greatly appreciated

[img]https://i219.photobucket.com/albums/cc175/carnumbernine/IMG_2845.jpg[/img]
They began germination about 3 weeks ago.[/img]