The green mold-like growth you’re seeing on your property could be Nostoc algae, a type of cyanobacterium that was formerly classified as blue-green algae. It often appears in lawns and other turf areas under certain conditions, such as overwatering or after a period of rain coupled with high humidity. Nostoc algae can thrive in areas where the grass is growing poorly due to soil compaction or excessive moisture.

Here are some key points about Nostoc algae:

It may appear suddenly in lawns under warm temperatures following rain.

It does not cause turf decline or death but colonizes areas with favorable conditions, like thin grass.

In its hydrated state, it’s a slippery, gelatinous, green substance, which can be a safety hazard.

When it dries out, it forms a black crust that can inhibit grass growth by preventing stolons from rooting.

To control it, improve drainage, reduce watering, and aerate the soil to reduce compaction.

More information at these links:

Nostoc: The mysterious green jelly on your lawn - Gardening in Michigan (msu.edu)

What is this strange looking slime in my yard? | A Fruitful Discussion (uga.edu)

Another possibility is slime molds, which are not true pathogens but can produce spore-like structures that might be mistaken for mold. They are usually harmless to the grass and can be washed off or removed by raking. More information at this link:

Turfgrass Diseases: Slime Molds (psu.edu)

It’s always a good idea to get a confirmed identification as to the type of mold this is. HERE IS WHAT YOU SHOULD DO! - Send all your images by e-mail to the MSU Plant & Pest Diagnostics Lab for a precise identification. The experts there can provide you with the best treatment options. Their email is <personal data hidden> - Please include your name – The lab will let you know if they need a sample sent. FYI – The lab may also ask for additional images too.

Their website is at this link:

Plant & Pest Diagnostics (msu.edu)

Their Contact Information is at this link:

Contact Us - Plant & Pest Diagnostics (msu.edu)

This link will explain the details on submitting a sample to MSU Plant & Pest Diagnostics Lab:

Submit Samples - Plant & Pest Diagnostics (msu.edu)

I hope this helps! Please let me know if you have any other questions – Thank You