On engines with belt-driven cooling fans, a fan clutch is often used to save energy and reduce noise. The fan clutch disengages slows or disengages the engine's cooling fan when extra cooling isn't needed. The fan pulls air through the radiator and air conditioning condenser when the vehicle isn't moving fast enough to provide adequate airflow for cooling.
St Augustine grass will go dormant when the soil temperatures fall below 55 degrees. If the soil remains warmer than 60 degrees all year, the grass will stay green. It will, however, slow in growth as the soil drops in temperature. Disadvantages of St Augustine grass. One of the disadvantages of St Augustine grass is its poor wear tolerance.
In the mid-west that's usually mid-November thru March when soil temperatures are below 50 degrees. Harsh winter weather will not harm dormant grass seeds.Frost seeding is a type of dormant seeding, overseeding moist soil before freezing weather. The natural freeze and thaw cycle of freezing soils will create small cracks or pockets, perfect for catching and holding grass seed.