Advice for Home Gardener from the Help Desk of the
UC Master Gardener Program of Contra Costa County
Master Gardener Help Desk Response: Thank you for contacting the UC Master Gardener Program of Contra Costa County about the strange fungus looking things growing on your mulch. Your photos were very helpful.
What you have is called a slime mold--not really a fungus, but similar to one. The most common one in our area is aptly called the 'dog vomit fungus' or 'scrambled egg slime' since it sort of looks like that when it's fresh. It is common to see this on recently-applied wood chips in landscaped areas, especially in spring. I have seen quite a few of these in my yard recently on chips that were spread last fall. The common ones start out a shocking yellow color, but as they dry, they turn brown and gray, and become quite dusty when disturbed.
Slime molds are not harmful to landscapes or people or animals, although if it appears on a lawn, it could cause a little damage underneath from shading and suffocation. Undisturbed, slime molds usually disappear within a week, but you can easily remove them by raking, or spraying them with a stream of water from a hose although that could spread the mold.
Slime molds are pretty interesting. They start out as individual cells and then coalesce into a single entity. They then start to move, although not very far (maybe a few inches) before they die. You can sometimes see their tracks in the morning.
You mentioned that you have begun using non-potable water in your garden. I don't believe that the non-potable water is cause of the slime molds your seeing. However, if you see any changes in the health of your plants which are being watered with non-potable water, feel free to contact us.
Please let us know if you have more questions.
Help Desk of the UC Master Gardener Program of Contra Costa County (MPL)
Note: The UC Master Gardeners Program of Contra Costa's Help Desk is available year-round to answer your gardening questions. Except for a few holidays, we're open every week, Monday through Thursday for walk-ins from 9:00 am to Noon at 75 Santa Barbara Road, 2d Floor, Pleasant Hill, CA 94523, although we will be moving this spring. We will notify you if/when that occurs. We can also be reached via telephone: (925)646-6586, email: ccmg@ucanr.edu, or on the web at http://ccmg.ucanr.edu/Ask_Us/ MGCC Blogs can be found at http://ccmg.ucanr.edu/HortCoCo/ You can also subscribe to the Blog (//ucanr.edu/blogs/CCMGBlog/)