I made these a few years ago with my students but before I even tried it out I made my own with my little cousin.
What You Need:
Hot Glue Gun
Begin by adding soil to the grass, add as much as you want to the size of what you want your head to be and then add some grass seeds.
Use a rubber band to secure it close and cut off excess sock. Then using rubber bands make some ears and a nose by grabbing a small chunk.
Glue on some googly eyes and a pipe cleaner. Soak the sock into water and place it on a plate or bowl. Make sure to keep the sock wet and grass should be growing in no time.
My students loved making their own grass heads and when the grass was long enough they got to give their grass head a haircut.
The following year, I did a different variation of growing grass, I bought small clear cups and took a photo of each student close up. Then I printed out their picture and taped it to the cup so it was their own hair that was growing.
There are many other variations on pinterest.