Why is my grass not greening up? By this time last year, it was beautiful! Grass, along with most plants, doesn’t go by what the calendar says, it goes by the temperature. We had another cold snap last night that dipped down into the 40s! Lower temperatures like that make the process of coming out of dormancy just a little bit slower. It is still happening, of course, just a bit slower than usual. Once we get some consistently warmer weather in our area, the grass will begin to green up quickly. Hope this helps, and keep on keepin’ on!