If you have problems with moss growing on your asphalt driveway, there are a few things that you can do to remove the moss and prevent it from growing again in the future.
Remove the Moss
Find a flat blade spade to scrape the moss off of the asphalt. Use only the amount of pressure needed to scrape the moss off of the surface without gouging the asphalt. Scrape until you have removed all of the moss as well as the dirt and debris that is giving the moss the organic material it needs to root and grow.
Purchase metal-sulfate base moss herbicide. Read the label to ensure that it is safe for use on asphalt surfaces.
Treat the area that you have scraped clean with the herbicide on a day in which rain isn't in the forecast. You want the herbicide to sit and work for a couple of days so that the roots and spores can be penetrated and killed before it is washed away by rain.
Prevent Future Growth
To prevent future growth, you must take the time to inspect your driveway regularly. Look for water that has settled after the rain or areas in which the sprinkler system is hitting the driveway.
Inspect the gutters and downspouts to ensure they are not allowing rain water to drain onto the driveway. Excess water will result in regrowth.
If you have areas of the driveway that dip and cause puddles to form, get a bucket of asphalt patch material and use it to fill in the holes and level the surface.
Trim back any bushes, shrubs and trees that shade the driveway in the areas that moss is typically a problem. Those plants are preventing the sun from reaching the surface and drying the moisture that will eventually lead to moss growth.
Sweep your driveway often. This will keep the organic material that the moss needs to grow to a minimum. Without the dirt, the moss won't be able to root and will no longer grow on your driveway.
If you notice that rainwater is washing soil from your yard onto the driveway, consider installing a raised border that will keep the soil from being washed onto the surface.
Talk with your local asphalt expert (such as one from Northern Asphalt LLC) to learn more about protecting your asphalt driveway from moss and other issues that could result in damage and premature replacement or repairs.