Grandma99
Cool Member
Posts: 66
Joined: Sun Jun 23, 2019 8:53 pm
Location: Oregon Zone 8b

Straw as mulch turning black?

I had a bale of straw seeding mulch with tack https://www.amazon.com/gp/product/B00GR ... UTF8&psc=1

It had been sitting outside in its original bag through the winter. I notice the bottom of it is turning black and, in fact, the 'black' is spreading a bit up the sides of it. Is that harmful to my plants if I use it as a mulch (top dressing)? Or is that 'black' just it decomposing because it got wet and it's not a problem? Is it a fungus or ?

ACW
Senior Member
Posts: 153
Joined: Mon Sep 13, 2010 11:20 am
Location: London

Re: Straw as mulch turning black?

I would say no problem,it will rot down nicely into a soil improver!
A gardener with a small shady back garden and a balcony with containers ,
biggest problem not enough sunshine !

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rainbowgardener
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Location: TN/GA 7b

Re: Straw as mulch turning black?

Probably mold or mildew from having the water held in. Once you spread it out in the sun, it will dry out and be fine. If you take it out of the bag before you let it sit, it is less likely to get mildewed. On the other hand, mice decided my straw bale made a nice winter home.....
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Grandma99
Cool Member
Posts: 66
Joined: Sun Jun 23, 2019 8:53 pm
Location: Oregon Zone 8b

Re: Straw as mulch turning black?

Thank you very much! I set the straw in the sun and the black is disappearing; it must have been a mold. :-)

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