Pour wheat grass juice into a jar, leaving little to no room at the top for extra air to get in, and seal it up well with a lid.
Place the jar in the freezer for at least an hour to help solidify it some. It doesn't have to be frozen solid when you take it out of the freezer, but rather should have more of a slushy consistency.
Place the jar in the refrigerator, where it can stay for up to 48 hours.
Mark the date and time when you put the jar into the refrigerator on the jar, so as not to leave it in there too long.
Pour fresh wheat grass juice into an ice cube tray.
Cover the filled tray with plastic wrap or place it in a sealable plastic bag to keep air out.
Place the tray into the freezer, making sure to set it in a safe, level area and avoid placing anything on top of it until the juice has solidified into cubes.
Take the ice cubes out as needed for use in drinks smoothies or for topical remedies.
Discard wheat grass juice ice cubes after six months.