Hello! Whenever I buy wheatgrass from the store, they always look so healthy and green, but when I take them home, they turn yellow almost instantly. I keep the wheatgrass by the window sill and water them when the substrate looks dry. In the recent attempts of keeping the wheatgrass alive, they did grow some new blades, but they looked thinner and less healthy than how they were when I first purchased them. Do I have to make any changes to my care? Should I try replanting them in a bigger pot?