Remove leftover leaves, dead plants, and lawn debris. Trim shrubs that brush against the house.
Plant grass seed in bare patches.
Apply pre-emergent weed preventer, if needed. Fertilize lawn, if needed. Make sure to use a zero-sulfur fertilizer (the number is on the bag).
Unless trees have been storm damaged, hold off tree trimming until autumn or winter when it's healthier to prune trees.
In the Summer
Move the lawn mower blade height up so that it cuts no more than the top one-third of the grass blade. Your lawn will be healthier, and you'll have fewer weeds if the grass isn't mown shorter than two to two and a half inches.
If it doesn't rain, water lawn weekly. Deep watering is better than frequent, shallow watering.
Take inventory of your yard. Are there areas of grass that never do well? Consider replacing grass with shrubs, perennials, or ground covers. Take photos now for winter planning.
Allowing grass clippings to remain on the lawn after mowing is actually beneficial. This process is known as grass-cycling.
Make sure to water in the early morning or late evening to prevent excessive evaporation.
In the Fall
Trim back any tree limbs that hit your roof or house. If needed, arrange to have trees pruned this fall or winter.
To ease raking, cut grass to a shorter length and try mowing over leaves. Use chopped up leaves for mulch. Rake leaves off lawns and streets (especially leaves clogging storm sewer openings).
If needed, fertilize your lawn: once in mid-September and again in early October. Also, consider aerating your lawn.
Deeply water trees and shrubs. Consider planting bulbs to enjoy next spring.
Shut off and drain outside faucets.
If you have an underground lawn sprinkler system, check for leaky valves, exposed lines, and back-flow protection.
In the Winter
Shovel sidewalks and driveways before foot or car traffic makes snow hard to remove.
Very carefully remove heavy snow from roofs to avoid ice dams. Hire a professional if you are not sure how to do this.
If your home is near a fire hydrant, shovel snow away from the hydrant so firefighters can access it quickly.
If your home is next to a storm sewer opening, shovel snow away from the sewer grate when temperatures begin to rise.