Moss/algae? growth on gravel drive

Asked May 1, 2017, 5:14 PM EDT

I have some sort of growth on my driveway that isn't phased by weed/grass killer. Two years ago I raked up most of it, in it's dry form, only to return 3 fold. When it's dry, it has a brittle crusty texture, after rain fall it swells up like seaweed of sorts.I tried to submit pics but they are not uploading.

Owen County Kentucky

1 Response

The following article on moss control was written by Amy Aldenderfer, County Extension Agent for Horticulture in Hardin County, KY:

The snow melts and rains fall to the earth giving moisture to the first plants that usually green up in spring: moss. Don’t be alarmed if this happens in your yard; one should not always consider lawn moss as a weed, but as a valuable ground cover.

Mosses are very short, primitive-branched plants that often produce a dense, green felt-like mat over the soil surface. Moss does help stabilize the soil and cover an otherwise unprotected soil surface.

Ninety-nine percent of the time, the presence of moss or algae in the lawn is due to heavy shade and poor drainage. In general mossy areas are more common in lawns of Kentucky bluegrass than those of fescue or perennial ryegrass.

Moss does not directly compete with lawn grasses but generally begins to move in after a lawn begins to thin or decline. Its presence is often associated with the following conditions: Shady or full-sun lawn areas that remain wet for long periods of time; areas of poor surface drainage; areas that are over irrigated; or areas with poor air circulation. Turfgrass does not perform well in these areas and will provide an excellent area for moss to become established.

Moss is also very common in shady areas where air circulation is poor but it will grow in full sun where the soil is very moist.

The following are several methods you can use to control moss or algae in your home lawn:

  • Improve the soil drainage by re-contouring the surface to prevent puddling.
  • Prune lower limbs from your shade trees (this does NOT mean to top the tree!!!); this will allow more sun to penetrate the tree canopy and will help with better air circulation.
  • Maintain adequate soil fertility in the lawn areas, be careful not to over or under fertilize especially where there is heavy shade. This can be done by taking a soil test.

Even if the moss is killed, it will rapidly recolonize an area unless you improve the conditions for the turf. Permanent moss control can only be achieved by growing healthy grass. Reseeding the areas with a turfgrass species that will tolerate shade may slow the regrowth of the moss.

If you have any questions, you are welcome to call be at the Owen County Extension Office at (502) 484-5703.

Steve Musen
Owen County Extension Agent for Agriculture and Natural Resources Education