Having Problems With Algae And Moss

It can be difficult to eliminate moss or algae from your yard. These organisms typically show up in turf areas because the growing conditions are not favorable for dense, healthy grass.

Mosses are small plants made up of fine stems that grow in a thick, spongy mat. Algae are thread-like green plants that form a thin, dense green scum over the soil surface. While neither moss nor algae are parasitic to turfgrass, algae can be especially troublesome. Once the green scum dries out, it forms a tough, black crust that is relatively impermeable to water and air.

Where and Why They Appear:

• Algae are more likely to appear in wet or humid, full-sun areas with compacted, waterlogged, fertile soils and thin or weak turf.

• Moss tends to thrive in wet or humid, shady areas—especially where the soil is acidic, infertile, poorly drained, or excessively thatched.
  

What You Can Do:

If you want to remove moss or algae from an area, you have two basic options:

• Avoid growing grass in these areas altogether.
  The growing conditions are likely unsuitable for turf, and attempting to establish grass may lead to ongoing frustration and poor results.

• Change the conditions.
  If you’re determined to grow turf in a mossy or algae-prone area, the site will need to be adjusted to support healthier grass growth. Recommended changes include:

• Soil testing.
  Determine the correct lime and fertilizer levels to improve soil fertility.

• Drainage improvement.
  Consider re-grading to improve runoff or installing subsurface tile drainage.

• Increase sunlight and airflow.
  Trim low branches on nearby trees and shrubs. In some cases, removing select trees may be justified. Choosing a shade-tolerant grass type will also help.

• Reduce soil compaction.
  Aerate the area with a machine that removes plugs of soil

• Avoid overwatering.
  Keeping the surface overly moist will only worsen moss and algae problems.
  

A Note on Products:

Chemical control of moss and algae is only a temporary solution. Unless site conditions are improved, the problem will return.

Once the area is improved, sodding or seeding is recommended to re-establish turf in areas that previously supported moss or algae—especially under shaded conditions.