Grass stops growing when it's not getting the things it needs to grow normally. Grass needs heat, light, water, and nutrients to grow. If it can't get what it needs, it goes on vacation (dormancy…). Dormancy protects the grass from environmental extremes (especially in temperature).

Does grass eventually stop growing?

When does grass stop growing? If the weather is warm enough, grass keeps sprouting. Generally, the cutoff point comes when temperatures drop below 50°F during the day. Usually, that's late October or early November, but some warm areas may push that date back to the beginning of December.

What happens if you let grass grow too long?

When you allow grass to grow long and then suddenly cut it, the mowing can send grass into shock. Grass roots become diminished and your lawn weakens, making it susceptible to insects and diseases.