Good chances are that after the long winter, there are at least some patches in your lawn that are either sparse or completely bare. Those spots can lend themselves to erosion, as well as spoil the overall appearance of your lawn. Fortunately, there are some fairly easy steps you can take to thicken or replace the grass in such areas.
First off, you will want to completely clear the area of anything but established grass. This means that any leaves, twigs, dead grass, or weeds must be raked out before you begin the process. This will help to ensure that the new grass you are about to put down will get the fullest possible amount of sunlight, as well as prevent the possibility of lawn fungi later on. Next, you will need to lay down your new grass seed. If possible, try to select a seed which is similar to the rest of your lawn. For example, if you have mostly bluegrass, don’t patch with a rye or fescue, as the patches will be noticeably different from the rest of the lawn. If your grass is already mixed, you can simply reseed with a basic mix intended to grow well in your climate region. To lay the seed down, use either a pull behind or hand-held spreader to help ensure that you achieve even coverage. You can also put down a starting fertilizer at this point if you want to give the grass a little extra boost. Make sure, however, that the fertilizer you apply is intended for new grass, as products meant for established grass contain enough nitrogen to harm new grass seed.
Once you have applied the seed and fertilizer, the rest is simply maintenance and patience. If you have a large area that you are patching, or if part of the area is on a slope, you will want to consider using a seed blanket to keep the seed from washing away. However, if you are only reseeding small, mostly flat patches, this is really not necessary. You will, of course, need to water your new seed every day until it germinates, for which reason a sprinkler and a timing system may be well worth the investment if you don’t have time to water the new grass daily. You will also need to make sure that the areas you have reseeded remain clear of too many leaves, branches, or other debris during this period.
If all of this sounds like more work than you want to get yourself into, you can also get any one of a wide range of patching products available on the market today. These products will contain seed, fertilizer, and mulch, all in one, and will therefore be nearly foolproof to grow. While these patching compounds do still require daily watering, they are much more forgiving if you miss a day, because the mulch that makes up a large part of them will help to retain water longer than ordinary seed will on its own. These products should only be used to patch small areas, as there is very little chance that they will match with the mix of grasses that is already making up your lawn.
Using either method you choose, you will be able to repair the thin spots in your lawn, thus restoring it to its best possible appearance. Once the grass is up, you will also want to begin a standard fertilization regimen throughout the year, in order to keep yourself from having the same bare spot problems in years to come.