What is this freaky fungus / spider nest / cat vomit?
February 5, 2015 1:07 PM   Subscribe

Two potted plants in my yard just came down with a freaky ... fungus? Cat vomit? Spider nest? It's a crust about 1-2" thick. It was on the top of one plant pot and around the base of another. Pictures (and a spider-related joke) inside.

Image gallery with four pictures
(no spiders visible)

We both thought it was cat vomit at first glance. But I've seen my share of cat vomit, and the color is right, but it doesn't exactly stay so crusty. Plus it's a lot of vomit for one or two nights. And it's not homogenous, but a yellow crust around a darker interior.

It seems to have popped up out of nowhere. On day two, it crusted over, or the crust got more defined lines on it. It also seemed to have a darker tan oily substance on it for a bit?

The yard has wood mulch over cardboard. The pots sit on top of that. These pots were about 15' apart. It popped up both places at basically the same time.

On one, the fungus was on top. On one, it was nestled around the base of the pot on top of the wood mulch. I've put that mulch in the compost bin now. It didn't seem any different from nearby mulch except for the very top.

I feared it was spreading under the mulch, but the plant with the fungus on top showed no sign of fungus (or filaments or roots or anything at all) near the water drainage holes that would connect the mulch of the yard to the soil in the pot.

Then I thought: fertilizer? something in the water? But two plants in between these two pots showed no signs of it and have the same watering regime. No ongoing fertilization, I am told. The original soil source of the two pots was different. The one with the fungus near the base had some eggshells and other organic fertilizer mixed in especially in the lower half.

There were some spiders on top of one; maybe it's a spider nest?

Please tell me my entire mulch yard is not about to explode into 200 square feet of cat vomit fungus with spiders that eat my faaaaiiii--
posted by ruff to Home & Garden (10 answers total) 1 user marked this as a favorite
I don't know what it is but we have it here in North Carolina, too - it pops up seemingly overnight in the mulch or soil near the house, in shady areas, a couple times a year and goes away after a few days.
posted by something something at 1:11 PM on February 5, 2015

Very close: its actual name is dog vomit mold. I looked into it a bit after getting it all over me and my kid when dropping him off at daycare (slimy! fluorescent yellow! fun!) It's gross but not hazardous.
posted by tchemgrrl at 1:17 PM on February 5, 2015 [2 favorites]

Say hello to Fuligo_septica. It's kinda ugly and gross, but nothing to worry about.
posted by sportbucket at 1:17 PM on February 5, 2015 [1 favorite]

It's not cat vomit fungus, it's dog vomit fungus! It's a type of slime mold, and harmless to your plants unless there's enough to smother them.
posted by Gneisskate at 1:17 PM on February 5, 2015

From wikipedia:
In Scandinavian folklore, Fuligo septica is identified as the vomit of troll cats.
posted by sportbucket at 1:19 PM on February 5, 2015 [15 favorites]

Are you guys serious? Amazing! Thanks. It's not as bright yellow as in some of those pictures, but this one looks just like it. I'll stop freaking out now. Nature is cool and so are all of you. Thanks.
posted by ruff at 1:25 PM on February 5, 2015 [1 favorite]

And it featured on an episode of Bones. The brainy beetle guy loved it.
posted by Kerasia at 2:27 PM on February 5, 2015

Gneisskate: It's not cat vomit fungus, it's dog vomit fungus! It's a type of slime mold, and harmless to your plants unless there's enough to smother them.
For the record, it's dog vomit slime mold; slime mold:fungus :: cactus:chimpanzee.

In fact, fungus is more chimpanzee-like than it is slime-mold-like.
posted by IAmBroom at 12:55 PM on February 9, 2015

Ooh! And I forgot to add: slime mold can move of its own "volition". Slowly, to be sure, but it can flow its mass towards food and away from threats (like dry surfaces). It was actually the inspiration for the 70's monster movie The Blob.
posted by IAmBroom at 12:56 PM on February 9, 2015

Thank you for validating my sense that it belongs in a horror movie! I spent Sunday raking back the mulch to create a nice defensible gravel perimeter along the front of the house.
posted by ruff at 10:45 PM on February 10, 2015 [1 favorite]

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