How to Control Algae in Your Lawn

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lawn algae

As I sit in my office staring out at about 12 inches of slowly melting snow, it’s nice to know that there are parts of the country where grass can be seen and lawn care has started. I recently received a picture from one of our Field Service Professionals in Opelika, AL of some algae growing in one of his lawns. Although lawn algae do not infect the grass plant, they can be a significant pest problem in home lawns. But before we get into lawn algae control, let’s understand why it happens.

How Do Algae Form on My Lawn?

Algae contain chlorophyll just like plants, but they produce thread-like growths similar to fungi. Algae grow in areas of a lawn that are thinned by poor growing conditions, areas that retain water due to poor drainage, or areas that experience excessive watering or extreme shade. The amount of algae can increase if air flow is restricted by fences or other structures. Additionally, they can grow across the turf canopy or on top of the mulch, and they generally grow best when it is warm and humid during the late spring, summer, and early fall. When they dry out, they form a crust that may repel water, slowing down turf recovery.

How Do I Get Rid of Lawn Algae?

The best ways to control lawn algae growth are:
  • Change the growing conditions, making it less suitable for algae to develop.
  • Prune low growing or dense foliage, and core aerate.
  • Improve the drainage patterns of a lawn. This can be a difficult task, but if the algae are a consistent problem, it may be the only solution.
  • Reduce the amount of water that the area receives.
  • Mow higher to allow the grass growing in a shady environment to receive more sunlight.
Once the algae dry out, they can be raked out, but care has to be taken not to damage the existing grass in the area. Once the algae have been raked out, the area can be core aerated and overseeded to improve the density of the turf. Please leave any questions, comments, or lawn algae stories you’d like to share in the comments section below.