A large swath of the central United States comprises U.S. Department of Agriculture hardiness zone 5, where winter low temperatures reach minus-10 to minus-20 degrees Fahrenheit. In includes metropolitan areas like Denver, Kansas City, Chicago, Indianapolis and Pittsburgh. While cool-season grasses like fescue and bluegrass dominate this tier, drier regions in the West may utilize drought-tolerant but warm-season buffalograss or blue grama grass for lawns.
Mention a lawn, and the issue of mowing likely arises as the most onerous maintenance task. While people may relish a tight, low-cut lawn on par with a putting green or household carpet, Michigan State University shares that higher-cut lawns have more extensive root systems, more vigorous and green leaf blades, tolerate lack of water better and tend to choke out competing weeds. Consider mowing your lawn at a height of 2 to 3.75 inches. Properly timed mowings allow gardeners to remove no more than one-third of the grass blade at each cutting, keeping the turf plants growing and looking their best.
The amount of water required for your lawn in USDA zone 5 depends on the quality of your soil and the current weather regime. Signs of water stress include curling leaf blades and failure of grass blades to pop back upright when walked on. Sandy soils need more frequent watering than loam or clay soils. Fescue and bluegrass need 1 to 2 inches of rain or irrigation each week in the hottest days of summer to remain their lushest green. Buffalograss can survive without a summer watering for upwards of four to five weeks. Over-watering a lawn is a common mistake in the United States, leading to high water bills, wasted water and threat of turf fungal diseases. Irrigate in early morning rather than just after sundown and always when windless.
To begin, allow the cutting from the lawn mower to naturally decompose on the lawn. These shreddings supply nutrients, especially nitrogen to the soil, allowing the grass to remain green and actively growing. As a general guideline, apply a high nitrogen/low phosphorus lawn fertilizer (20-5-15) to cool-season lawns around Easter, Memorial Day and Labor Day each year. Consult product labels for recommended dosages. Conduct a soil test, too. If your topsoil is naturally rich and fertile, the need and expense of fertilizers may not be warranted. Fertilize warm-season turf in midsummer and again at Labor Day.
Primary lawn concerns include infiltration of weeds and root-eating pests like Japanese beetles. Rather than relying on herbicides and pesticides, determine a threshold of damage tolerable before such chemicals are needed. A healthy, properly cut and watered lawn can withstand common pest problems quite well before visibly looking bad. Remove weeds before they set seed and get scattered by the lawnmower.
In bare areas of the lawn, seeding cool-season grasses in the early spring or around Labor Day allows for moister soils and less chance of hot, drying weather. Seed in late fall only in areas where a protective snow cover will keep the dormant grass seed in place to germinate first thing next spring. Sod rolls may be placed anytime in spring or summer but must be watered well to make sure roots don't die and have a chance to penetrate into the topsoil before the cold winter.
Aerating the lawn--the removal of small core pellets of thatch and soil--can improve the health and vigor of lawns. Aerating alleviates soil compaction, which is most common in areas with lots of foot traffic. Aerate once in early spring to early summer annually.