This article is by TORO
It takes work, but it is not impossible to give your lawn a facelift. While it may take two or three growing seasons, your hard work will eventually pay off in a beautiful lawn. Follow these steps to help wake up a tired lawn:
Step 1: Remove Thatch and Weed Buildup
Thatch is un-decomposed stems and roots that accumulate near the soil surface. Dig up a small, triangular-shaped plug of turf several inches deep. If the spongy layer above the soil is more than ¾- to 1-inch thick when you compress it, it is time to have your lawn dethatched. The best time to dethatch is in the spring or fall when your lawn is thriving.
Step 2: Fill Depressions and Level Bumps
Poor grading, uneven settling, or the decomposition of buried tree stumps, logs, or roots can cause depressions and bumps. While you are dethatching your lawn, check for bumps and depressions. Mark any irregularities with latex spray paint so you can find them easily when you are ready to level.
Smooth slight depressions by topdressing—applying a combination of topsoil and compost—the surface topsoil. A wide landscaping rake is the best tool for this job. When handling larger depressions—those more than an inch or two deep and several square feet in area—raise the sod; fill the depression with a mixture of soil, humus, and fertilizer; replace the sod, and press it in place. Be sure to keep repaired areas moist, or the edges will dry out and turn brown.
To level small bumps, raise the sod using a sharp spade, and remove the necessary amount of soil beneath it. Cut out at least a 2-foot x 2-foot section of sod. If you lift smaller patches of sod, they will likely dry out and die. While the soil base is exposed, mix in some compost and fertilizer. Soak the area using a hose; press the sod back into place; then sprinkle some soil into the seams.
Step 3: Adjust Your Soil’s pH
It is best to test your own soil or obtain test results from a professional testing service, before applying any amendments. Conduct soil tests and learn what to do to correct your soil’s pH level.
Step 4: Add Nutrients
Use a slow-release fertilizer, and avoid putting down more fertilizer than you need. Adding too much nitrogen can cause rapid growth and a thinning of plant cell walls, which makes grass more susceptible to disease. The excess fertilizer may also leach and eventually find its way into waterways, polluting them.
When restoring a lawn, apply the fertilizer as recommended by the results of your soil test.
If you did not test your soil, apply a slow-release fertilizer with a nitrogen-phosphorus-potassium ratio of 3-1-2. Apply about ½-pound of nitrogen per 1,000 square feet of lawn. It is best to apply fertilizer at least a week prior to spreading seed. Water the fertilizer into the soil if it does not rain before seeding.
REMEMBER: you shouldn’t feed a stressed lawn—adding nutrients without knowing what nutrients are required is like taking medicine when you don’t know what’s wrong
Step 5: Increase Organic Matter and Microbes
Applying fertilizer will not help if your soil does not contain an adequate population of microbes; you need billions of these microscopic organisms per handful of soil. Your soil must contain 2- to 5-percent organic material to have a thriving microbe population.
Step 6: Aerate Compacted Lawns
Aeration allows grass roots to deeply penetrate the soil and for fertilizer and organic matter to reach the roots. Avoid aerating during dry summer months because you may damage an already stressed lawn. Also, avoid periods when weed seeds are prevalent to prevent further weed infestation.
Step 7: Prepare the Surface and Overseed It
Before you begin, choose the seed that is best for your geographical area and buy the amount you need to cover the size of your lawn.
You have several tool options for spreading seed evenly and at the recommended rates. They include your own hands, hand-held, and walk-behind spreaders, and slit-seeders (power seeders), which are powerful machines that cut shallow slits in the soil and sow seed at the same time. Slit-seeders, available at many rental stores, are the preferred tool, especially if you were not able to remove all thatch prior to overseeding.
Before sowing seed, use a thatching rake to roughen the exposed soil to a depth of ½-inch. Second, apply seed to the edges of the area you are sowing first. Third, divide your seed, and apply half while walking in one direction and the other half while walking in a perpendicular direction. Spread extra seed on bare areas, and lightly cover the seed with a mixture of compost and topsoil. Then spread more seed on top. If you were not able to remove all thatch, or if you have a higher percentage of weeds, sow a little extra seed. If using a spreader, set it to deliver the seed as recommended by the seed producer.
Overseed in the late summer and/or early fall. You may also try this technique in early spring, but the fall gives the young grass plants a better chance to germinate, establish strong roots, and store food needed for a head start in the spring.
Overseed in the spring or early summer to give young grass plants a better chance to germinate, establish strong roots, and store food needed for a head start in the fall.
Step 8: Take Care of Young Plants
Your efforts to restore your lawn will be in vain if you do not care for the young grass plants as the seeds germinate and begin to grow. The most critical need is to apply water at least twice a day, assuming no rain. If the soil dries out, the seedlings will not germinate or will soon wither and die.
To maximize the germination rate, soak your lawn on the same day you sow the seeds. On the next day, assuming no rain, lightly sprinkle or mist the lawn for about five minutes morning and afternoon. Be sure you have moistened the soil to a depth of 1-inch. Keep the overseeded lawn moist until the young grass plants are 2-inches tall by repeating a light watering every day after periods without rain. This will take four to six weeks.
Stay off the seeded areas, except to fertilize once more. If needed, apply a second dose of a ½-pound of nitrogen per 1,000-square feet six weeks after germination. However, do not add more fertilizer if the grass will soon be dormant.
When the grass is 2-inches tall, resume normal watering patterns. Begin mowing again once the grass reaches 3- to 4-inches tall before it is long enough to fall over. Make sure your mower blade is sharp; a dull one may tear up young grass plants.