Is it too cold to water your lawn in 40 degrees?
Any temperature below 40℉ is too cold to use sprinklers to water your lawn. Although air temperatures are still above freezing, water droplets clinging to grass blades will be exposed to wind chill or colder nighttime temperatures, which may freeze them solid. This can result in brittle, frozen grass.
The colder weather does not evaporate moisture from the lawn as quickly as it does in the warmer weather. Most lawn experts recommend watering your grass until the soil or ground temperature reaches the 40-degree Fahrenheit mark.
It is best to water the grass the day before a freeze because the wet soil acts as insulation to the grassroots. Roots are more likely to freeze if the ground is too dry. Stop watering when the ground freezes.
However, if the temperatures do dip down into the 20's, or temperatures remain below 32 degrees for an extended period of time, your irrigation system can be damaged.
Spring seeding and dormant seedings won't germinate until soil temperatures are above 50 degrees Fahrenheit. A range of 50-65 degrees is optimal (measured at a depth of 2 inches). Once we reach this soil temperature, the process of germination will begin.
When temperatures are consistently warm in fall and winter, take advantage and keep the plants hydrated. Avoid watering when temperatures are below 40°F or when sustained freezing temperatures are expected within 24 hours as this water will freeze and not be available to the plants.
Starting in November there is no need to water your lawn as much as at the start of autumn. Be careful not to overwater. Overwatering can lead to drowning your lawn and is both a waste of money and resources. We recommend winterizing your irrigation system before freezing temperatures.
When your lawn goes dormant, irrigate once or twice a month. Winter irrigation keeps the grass root cells full of water and acts as an insulator, giving the cells a better chance to withstand freezing temperatures. And moist soil adds even further protection to the roots because it stays warmer than dry soil.
When temperatures are below 40 degrees, you may want to wait until mid-day to water, still allowing time for water to soak in before nighttime freezing. If it has just rained, or it is expected to rain, don't water. Grass grows more slowly during the colder months, requiring less watering and mowing.
In water that is 32-40 degrees Fahrenheit, a person can typically swim for up to 7 minutes before exhaustion.
Should I water plants at 40 degrees?
Water for Plants During Winter
Just make sure that the ground doesn't stay soggy, as this situation creates a serious hazard for plants from root rot as well as suffocation. As a rule of thumb, water when the soil is dry to the touch, the temperature is not below 40 degrees F. (4 C.)
Avoid watering grass on a hot afternoon when it's 95 degrees or higher. The best time to water grass is at dawn or in the early evening. Water deeply three times a week instead of a little water daily.
