Why Restore Your Lawn?
A restoration allows improvement of your lawn without removing the existing turf. While restoring your lawn is not nearly as labor intensive as removing all of your turf and starting over, it may require several weekends of work.
In general, the best time to begin restoration of a lawn is in late Spring, before temperatures are too hot. It may take your lawn several weeks to recover.
Removing Thatch and Weeds
When beginning a lawn restoration, the first step is to remove any thatch buildup - even low levels that would otherwise be acceptable. Unless you can expose the soil between the old grass plants, the steps that follow will have poor results.
The best time to dethatch is when your lawn has freshly broken dormancy in Spring - not when it's stressed in the heat of summer or cold of winter. To begin, set the height adjustment on your mower to cut the grass about 1 inch inch height or so. Mow the entire lawn. Short grass will make dethatching and surface preparation easier. If you will be overseeding the lawn, dethatching will also improve seed germination rates as more seed will make contact with the soil and seedlings will have greater exposure to the sun.
The easiest way to remove thatch from a lawn that is over 3,000 square feet in size is with a power power dethatcher. A dethatcher can be rented from your local tool rental store. For smaller lawns, or lawns with a thin 1/2 to 1-inch layer of thatch, a manual thatching rake will do a satisfactory job. When using a power dethatcher to remove average amounts of thatch, and to scarify the soil, set the blades to cut 1/8 to 1/4 inch into the soil. Make several test passes on an inconspicuous area of your lawn to judge how much thatch (and turf) will be removed. If too much or too little is removed, raise or lower the blades accordingly. The spacing between blades can be adjusted on some machines, but this is difficult to do, and is best done by the rental store staff. The blade spacing for Bermudagrass and Zoysiagrass is 1 to 2 inches. Most rental store owners will know the optimum settings for the grasses grown in your area.
When using a vertical mower to dethatch, make several passes over the lawn in perpendicular directions. It is important to be thorough. Remove the thatch you pull up after each series of passes and add it to your compost pile. When you have finished dethatching, remow your lawn to a height of 1 inch.
Fill Depressions and Level Bumps
While you are dethatching your lawn, check for bumps and depressions. These may have been caused by poor grading, uneven settling, or the decomposition of buried tree stumps, logs, roots or construction materials. Mark any irregularities with latex spray paint so you can find them easily when you are ready to level them.
To level small bumps, raise the sod with a sharp spade or sodcutter and remove the necessary amount of soil beneath it. Cut out at least a 2 by 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. Watersoak the area using a hose and press the sod back into place. Keep the area watered to prevent lawn brownout.
Slight depressions can be smoothed over with topdressing. To topdress, apply a mixture of native topsoil and compost. Native screened top soil is recommended over top soil sold in bags. Fill depression and rake smooth with a landscape rake. When handling larger depressions - those more than an inch or two deep and several square feet in area - raise the sod and fill the depression with a mixture of screened native top soil, humus, and fertilizer. Then replace the sod, and press it in place. Be sure to keep repaired areas moist, or the edges will dry out and turn brown.