Answer: The best time of year for extensive lawn work is in late summer/early fall. You should begin by running some basic soil tests to check fertility and pH levels. Then fertilize and/or add lime according to the test results.
If the soil is compacted, you may want to do a core aeration (pulling up plugs or cores of soil, not the type that just punches holes with spikes) along with a top dressing of compost as well. Those steps should help improve the soil conditions for the grass.
Good care includes mowing correctly. Set the mower blade high at three inches and mow often enough that you do not remove more than one third the grass height at a time. In spring, this can mean mowing more often than once a week. In summer, you may mow less often.
Watering may be needed for an established lawn in times of extreme drought, however a natural protective mechanism of lawn grass is to go dormant during dry spells and then recover once it rains again. How long it can go between watering/rain depends on the specific type of grass you are growing in your lawn.
Newly seeded areas must be kept evenly moist until the seed germinates and the new grass becomes established. Hopefully a fall planting will receive moisture from the season rains so you are only watering as needed to supplement the rain.
Kentucky 31 is an older variety of bluegrass. Bluegrass is pretty in a lawn but it absolutely must be watered heavily in summer, so in some cases it is not the best choice for a lawn. There are many good lower maintenance lawn grasses besides bluegrass (such as fescues) and many newer improved types of grass seed on the market.
I would strongly suggest you work with your local county extension to develop a plan for your lawn. They should be able to help you with the soil testing and suggest the best varieties of grass for your lawn conditions and expected maintenance program.
In the meantime, you may find the following information helpful in planning your lawn care/improvement project this fall.
Good luck with your lawn!
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