Fall is the best season for starting or rejuvenating lawns because Minnesota lawns are made up of cool season grasses, fescue, perennial ryegrass and Kentucky bluegrass, which have growth peaks in the spring and fall. All lawns need water and mowing all during the growing season and depending on the lawn condition, fall is the recommended time for fertilizing, aerification, thatch removal or weed control. Adequate watering or rainfall is one to one and a half inches per week. Well drained or sandy soils may benefit from two lighter watering sessions per week instead of one. Early morning watering is best. Less of the water is lost to evaporation because the temperature and sunlight levels are lower. Watering in the evening encourages turf diseases to develop because the grass does not have time to dry before the temperature drops. Lawns should be mowed until the time of the first snow. Three inches is a good height which will encourage the root system to develop deeper into the soil and keep the lawn in good condition all year long, and especially over winter Mulching the grass clippings and allowing them to drop back into the soil is a good way to recycle the nutrients and to reduce the need for fertilizer. Lawn clippings decompose easily and usually do not cause thatch to occur.Fertilizer will help the lawn to be in the best possible condition to survive the winter. Fertilizer packages have three numbers on their labels. The first number is the nitrogen level which promotes growth and root development and this number is usually the highest. The second number is phosphorus which is also required for growth. However, phosphorus is often naturally found in the soil and because it can run off the lawn and accumulate in our lakes and streams, it is no longer allowed in lawn fertilizer, except for the seeding of new lawns. The third figure, potassium, is also required for growth and also may naturally occur in the soil. A soil test is the best way to determine whether or not a lawn needs any of these fertilizer components and how much should be added to the lawn. The thatch often seen on lawns is made up of stems and other denser material that has not decomposed and remains on the soil surface for a long period of time.Unless this layer is more than a half inch thick, it does not need to be removed.Thatch is removed with a vertical mower that has blades which cut the thatch and leave it on the surface of the lawn where it can be raked up and removed Lawn aerification is needed only in soil that has become very compacted so that it does not drain well. Aerification is done with a machine that makes holes in the ground about a half inch wide and up to three inches deep to allow air and moisture to reach the grass roots. If fertilizer is applied after aerification the holes will soon be refilled with new growth.Not all weeds are controlled by a fall application of a herbicide but a majority of them can be eliminated at this time. After identifying the weed, use the recommended herbicide following the label directions exactly to avoid harming humans or desired plants. For further help with fall lawn care, access the University of Minnesota Extension website,www.extension.umn.edu/gardeninfo. Help with home horticulture is available by calling our voice mail, 444-7916. 
