Control of "green slime" in lawn and flower beds

Asked April 10, 2015, 7:49 AM EDT

Please explain how I can control the "green slime" that grows in the lawn and the flower beds.

Bennett County South Dakota

3 Responses

Perhaps you are referring to slime mold. one of the most common is dog vomit slime mold, named because that is what it appears to be. There are many different types and though not a pretty sight, they are basically harmless. Information from Extension source below on what it is and how to control it: If you think it is something else, a picture would be helpful.

What is a slime mold?
Slime molds are not true fungi but primitive fungal-like organisms. More than 700 different species of slime mold exist. Those found on lawns or flowerbeds have a two-part life cycle. During warm, moist weather the slime mold lives as a shapeless, growing blob called a plasmodium. The plasmodium may be gray, cream, colorless, bright yellow or orange. A plasmodium can slowly creep across the ground, moving like an amoeba and consuming bacteria, fungi and organic debris as it moves. Beds of shredded, decaying wood mulch are prime real estate for slime molds because mulch is especially full of tasty fungi and organic debris. Those that live on turf feast on the fungi and bacteria that live in the thatch. When the environment dries out, the plasmodium transforms its shapeless body into many small, often stalked, fruiting bodies that are full of dust-like spores. Sometimes, a plasmodium moves itself to a dry spot to accomplish this transformation. The dry, sporulating slime mold often looks hard and crusty. The tiny spores can remain dormant in the soil for years, waiting for another period of moist weather, when they germinate and each release a small, motile cell. Two motile cells fuse together and grow to become a new plasmodium, starting the cycle anew.

How can I get rid of it?
Slime molds are usually only a cosmetic problem, and they do not severely harm the plants they grow on or near. Slime molds on turf may cause the grass to temporarily turn yellow because they block the sun, but once the slime dries out and disappears the grass quickly recovers. In only extremely rare cases, a Fuligo plasmodium has been known to crawl onto a small garden plant and inadvertently suffocate it. Slime molds are usually considered beneficial organisms because they decompose dead organic matter and help the cycling of nutrients. They also may consume plant pathogenic fungi or bacteria in the soil, helping to reduce plant disease.

Although they are harmless and even helpful, it is understandable that most gardeners do not welcome homely slime molds. Because slime molds thrive in a moist environment, the best way to get rid of them is to allow them to dry out. Raking the mulch or grass to introduce air helps to accomplish this. Slime mold on turf also can be simply mowed off. Heavy thatch in the lawn provides a reservoir of organic matter and moisture, so reducing the thatch layer may help reduce slime mold growth. Chemical treatments rarely work.

The simplest thing to do is to learn to tolerate a little slime now and then. Untreated, a slime mold quickly disappears on its own as the weather dries out and it returns to its dormant, and invisible, spore stage.

Image result for green slime in the lawnThis is what it looks like in my flowers and my lawn. It is not yellow as you have described. Are you sure that we are both discussing the same problem? If one steps on it, it is so slick that you will fall to the ground.

There are many different types of slime mold from white to yellow to green etc. Many are slick and I have attached a website with pictures of many types of slime molds and some resemble the picture you sent. I have also attached your county agent in case you want to check with her. I tried to find the name of the turf specialist currently at SDSU but did not find a name. However you can call the Extension number below to try and find a turf specialist.

SDSU Extension 605-688-6191

Bennett County
501 Second Ave., Ste. A, P.O. Box M, Martin, SD 57551 | 605.685.6972

Kari O'Neill, Community Development Field Specialist