Here are essential ways to make a perfect lawn for cool areas:
Cleanup
Rake the lawn. Rough up bare or thin spots and add grass seed. Sprinkle them with a little special starter fertilizer, high in phosphorous (P), if you have it.
Fertilizer
Apply fertilizer three or four times a year, starting in early spring, again in mid-May, then around Labor Day, and finally an organic fertilizer in late fall. But beware, too much nitrogen makes thin cells walls and fragile grass. Use only the right amount, more is not better. Iron (Fe) makes grass greener. Potash (K) makes it tougher. There are many, many fertilizers for each phase of growth and for each season, as well as alternative lawn care programs that add plant hormones and beneficial organisms.
Lime
Grass likes a pH 6 to 6.5. Lime is usually needed only every few years, but test the soil first.
Mowing
Start mowing when the the spring shoots get 3 to 4 inches high. Try to remove no more than 1/3 of the green shoot at each mowing. Current theory is that mowing high ( about 3 inches) shades out weed seeds, especially crabgrass. For a perfect lawn, mow regularly and often. Keep the blade sharp.
Mulch the Clippings
Best for the lawn is to let chopped up, small grass clippings stay on the lawn to compost and return nutrients to the soil. The fastest way to mow is in a big circle, not up and down with many turns. However, if you love your lawn, you probably prefer a particular pattern to the mowing lines.
Crabgrass
There exists a passionate hatred for this spreading greenery whose seeds germinate over a long period of time. Pre-emergent herbicide control may be applied (with fertilizer) in early spring, however, herbicides may not be a good idea where there are children or dogs. An alternative safe crabgrass control (made from corn gluten meal) is available but has to be re-applied for two or three years to get reasonable results. Combined with mowing high, overseeding spring and fall, aerating, and yes, hand pulling of the light green seedlings, crabgrass can be kept under control.
Pesticides
Use them only when needed after a particular problem has been identified. Then treat just that problem. There are lots of books on the subject or get professional help. Fortunately, there is a new, safer pesticide called Merit for white grubs in the lawn. (Grubex is the same thing.) Apply it in May for control of the new grubs which will hatch in summer. It works slowly and is most effective on small grubs.
For more immediate insect control, one can apply a strong chemical pesticide (after identifying the insect). But remember, if children or dogs play on the grass, they will be exposed. Better to let the kids grow up first.
Water and Sprinkler Systems
Ideally a lawn likes one inch of water about once a week to encourage deep, healthy roots. Fight to get your sprinkler company to cut your frequency to once a week, twice at most. Overwatered grass is shallow rooted, fungus prone, soft and fragile. Have a manual sprinkler override to turn it off when rains are heavy and don’t begin irrigating until the first long heat wave in late May or June. If you pay for sewer charges based on how much water you use, try to get your sprinkler system on a separate water meter. It will save sewerage charges.
Fine Tuning
Aeration (making holes for air in the soil) helps a compacted lawn so, if you own some, wear spikes when you work on the lawn. Topdressing with a fine compost or topsoil helps too. Current theory suggests that a late fall application of organic fertilizer will melt thatch.
Overseed
Lawns grow best in the cool of spring and fall, so twice a year regularly apply grass seed at the start of each growing season to replace all the little grass plants that didn’t get all the love and attention they were crying for.