You might consider summer as the time for watering the lawn, but don't think you can stop watering grass in the fall. Even those who live in cooler climates aren't off the hook. Along with mowing the grass to an optimal height, fertilizing it, and raking leaves, proper watering is one of the most critical aspects of fall lawn care.
So when should you stop watering your lawn in the fall?
After the ground freezes, it would be pointless to water grass because the frozen ground would act as a barrier, blocking the water's path to the roots.
Plants survive the lack of water by going into dormancy, a sleep-like state in which they don't need irrigation.
If your type of grass is a cool-season grass, then fall is an important growth period for your lawn. Grass does keep growing for a good part of the fall, even if you don't see as much growth on top. Instead, much of the growth occurs underground in the root system. This is crucial to build a solid foundation for your lawn and to help it repair any damage that occurred over the summertime. Don't deprive it of irrigation during this critical time!
As important as it is to water your lawn in the fall until the ground freezes, it's just as important not to overwater it. Overwatering can harm the root system of grass, and the excess moisture can put the lawn at risk for fungal diseases.
If your area receives sufficient rainfall in autumn (around 1 inch per week), you might only have to water areas that have been overseeded or where new lawns have just been started. But if a relatively warm, dry spell occurs, be prepared to water the lawn just as you would in the summertime.
Watering in the early morning is best because the grass has all day to dry out before night falls. For the same reason, the evening is the worst time to water the lawn. This is one reason why automatic irrigation systems come in handy. They have timers you can set, so you don't have to be an early riser to get the grass watered at the right time.
An adequate water supply for grass roots is essential for proper nutrient uptake during growth periods. If your lawn isn't sufficiently absorbing nutrients, it won't achieve optimal health and might not survive a harsh winter.