plant grass

Hello, first of all - sorry for my English, I'm from Germany. As you can see on the pictures, there are some weird green plants, that I have to craft to get the achievement "craftmaster". But how? It has something to do with the mods, I guess. All of the mods, that I'm using, are on these...

On the last day of winter (28th) plant just a few grass starters where you want tall grass to grow. On the first day of spring you will get big green patches of grass growing in those places.