Since Cat Grass is actually wheatgrass sprouts, it helps to think of it as produce and care for it in a similar way. The average lifespan of wheatgrass is about 2 to 3 weeks, depending on a variety of factors like the temperature, humidity, etc. The good news is there are things you can do to extend the life, like storing the pots in the refrigerator when your pet is napping or out on a play-date. Keeping it trimmed helps, too, and you can sprinkle the trimmed ends on your pets’ food. Transplanting to a larger pot will not extend its viability.