How to Avoid Green Slimy Ooze From Growing On Your Lawn.

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nostoc algae

What is this Green Slimy Ooze?

During the last couple of years, I’ve received several questions about a strange green slimy ooze growing in lawns. So after doing some research, I learned that it is a type of cyanobacterium, formerly called blue-green algae. This green slimy ooze has been called many colorful names over the years, including witches, butter and star jelly, which is based on the belief that the ooze was indeed the remnants of shooting stars.

Why do I have it?

Nostoc Algae will occasionally appear after excessive rain falls and will not only develop on lawns, but also on sidewalks, driveways and other paved surfaces where it can even become a slippery hazard. If it is developing in a lawn, it usually does so in areas where the turf is growing poorly, soil is compacted, area retains moisture or if fertilizers used  are high in phosphorus. The important thing to understand is that the Nostoc Algae is not the cause of the decline in the lawn. It develops in areas that provide the ideal conditions for its growth.

How do I get a rid of it?

Once the Nostoc Algae develops in a lawn, it can be very difficult to remove. The gelatinous mass will dry up into a black crust that reforms when favorable conditions return. If you have seen this grow in your lawn, the best solution is to improve the growing conditions where the algae developed. This may include improving the drainage in the area.  Core aeration is a great process to help reduce compaction. Unfortunately, there is a risk that the algae will be distributed to other parts of the lawn during the aeration process. This may require applying a moss and algae control product to your lawn as a supplement to core aeration. There are several commercially available moss and algae control products available at hardware stores and garden centers.  Be sure to follow all label directions when using these products. If the algae forms on paved surfaces, use a shovel to scoop it up and throw it away. Nostoc is not a very common problem. I have never actually seen it on a lawn and have only seen pictures of it.  Normally this problem develops in late spring. But the picture above was sent to me by a manager of our Baton Rouge, LA office from when he observed it in December. As mentioned in a previous blog post, if the conditions are right for a disease to develop, and algae could be included in the disease family, it will develop. Do you think you might have Nostoc Algae in your yard? Let us know by either commenting below or asking your local Spring-Green.