White powdery stuff under my mulch - HELP what is it??

I went to my rental property to do some maintenance on some flower-beds, and when I pulled up some garden light wiring from under the mulch (which was texas-hardwood with cow-manuer for added fertilizer), it showed some white powdery stuff underneath. Since I pulled pretty hard on the wire, the white-stuff went everywhere in the air and i'm afraid I inhaled alot of it, not to mention got it all over my clothes.
I live in Austin, Tx and as you can imagine the heat around here is pretty heinous. The renter hasn't taken care of the flower beds with proper watering and has done a good job of ensuring everything is pretty dried out. If it wasn't for the xeroscape plants I put in, everything else would be dead.

Anyways, my mind is wandering on what it could be and I'm trying to find some answers. Everything I've found on the web so far talks about white mold on plant leaves, but this was about 1 inch under the mulch.

Anyone know what is it?

T.... It hard to say without a picture. It could either be overwintering spore s from a plant that was there before which means it a disease ,or it could be a good fungi that helpign in the breakdon of the mulch chips.

If you have had lots of water there and the mulch been wet or damp for long time, I would guess it a bad fungi.

Anyway you try and take a coupel of pic. what your looking at and maybea close up to s e what type of hyphea structure it is?

What are the conditions like down in yoru mulch? Wet dry, damp, see any leftover plant roots or dead foliage lying around there on top of that area?

It could be mold growing in the mulch, I've seen stuff like that before. It never seemed to hurt the plants but I never had a ton of it.

Yikes, pictures. I'm afraid I don't have a digital camera (yeah, I know, I'm thinking the same thing).

Well, the conditions under the mulch were super-dry. Everything was super dry cause we're still in winter and cause my tenant does a good job of forgetting to water anything....along with the grass (*eek*). The plants seem ok in the flower-bed since they're native plants that are used to not having alot of water.

I guess I'll ask my landscaper to re-do the flowerbeds and scrape away the top layer of mulch & soil ... put down new top-soil & mulch ....

ces-la-vie!

I had the same stuff. I have raised veg beds then mulched around them in a corner of the yard. Turn over the red dyed mulch and you see white hard powder clumps in spots. Must be bad mulch. It's also the only spot in the yard where mushrooms keep growing!

Tpot... If your conditions were dry then I would not have the beds redone. No need to go to that expense. That just natural break down happening. That good microbial activity going on.

Tir Na Nog... If you have mushrooms growing you need to back off the water. Mushrooms grow in very moist wet conditions. Try and let that area air out and then keep on the dry side. Soon your mushrooms will disappear.

Fungal mats will grow under hardwood mulch. It is actually a decomposer, but the problem with it is that it often forms an impenetrable mat that water can't get through. The water doesn't soak into the ground, but runs off laterally. If it's bad enough, plants can die from lack of water, even though it has been irrigated. I have used it and lost plants. I don't use it any more.

I have alot of that stuff in my rose beds and it doesn't seem to be a problem.

Maybe it depends on the climate, I don't know. Maybe it has to do with how long the hardwood has been composting. Again, I don't know. Mercer Arboretum in Houston had the same experience. I volunteered there so I knew about it, but one day my DH had the yard guys mulch my back flower beds. When I came home and saw what went down I was very upset, but I was far too lazy to rake it all up! I suffered the same fate that Mercer had. When the plants started to get sick, I pulled up some of the mulch and dug through the fungal mat, and the soil was dry as a bone. And I had been watering.

Maybe it just needs to be broken up periodically? Come to think of it, I do have a problem with my dirt being dry after I water, but I thought it was because the water was running down the mole tunnels instead of soaking in.