Photo credit: Purdue Plant and Pest Diagnostic Lab

In this month’s column of In the Grow, B. Rosie Lerner, Purdue Extension Consumer Horticulturist, addresses algae that can pop up on stone, concrete, gravel or even lawns this summer as we are getting large amounts of hot, rainy weather.

This terrestrial algae known as Nostoc can look unappealing and also be a slippery safety hazard, but unfortunately, there isn’t much to do about it. Raking the algae will just spread it to larger areas. Keeping the area aerated and dry as much as you are able can help a little with controlling this algae, and applying copper sulfate will also shrink it a little bit, but it will just reappear when warm, rainy weather conditions occur again.

To read Rosie’s full response on terrestrial algae this summer, please check out July’s In the Grow Column.

Resources
Warm, Wet Conditions Prime for Algae, In the Grow, Purdue Extension
News Columns & Podcasts, Purdue Agricultural Communication
What is That? Buckeye Yard & Garden Online
Nostoc: A Green, Jelly-Like Substance Growing in Lawns, Michigan State University Extension

B. Rosie Lerner
Purdue Extension Consumer Horticulturist