ashy powder like dust on my wood chips that have sat for awhile: is it mold? (answer: yes)

Hi, I have recently had two loads of free wood chips from our local power company who have been working in our area.  The first load sat there a few weeks before we began to use it.  The very little green looked to be like from some kind of evergreen.  When we began to use it, there arose an ashy powder like dust.  My husband was worried that it might be some kind of mold spores?  I was wondering if anyone might have some answers for me?  Also, the load that came today had a lot more evergreen pieces and had a very strong Christmas tree smell😀.  Are the evergreen tree mulches okay for flowers and vegetables and just for improving the soil?  I Saw some info online that said it wasn't and my heart began to sink because we have been so excited to get some free wood chips.  Thank you.

This will probably spark the woodchip debate again, but there are a few reliable bits of info that are necessary to know about woodchips.  Not sure where you are, but that might matter when it comes to redwood trees or red cedar that do have some plant growth inhibiting qualities.

Can you call the place that provided the woodchips and ask them what kind of tree  trimming they came from?  

A Christmas tree smell does imply pine or cedar.  Could the dust be pollen?  Pines and cedars can a lot of light yellowish pollen.  Tap a few pieces onto a white piece of paper and see if any bugs land on the paper.  Usually wooden trunks and limbs do not have powdery mildew, like what forms on rose leaves sometimes.  

In general, woodchips are carbon, and when they are green they will soak up water that has nutrients that ought to be meant for the plants.  So they will absorb some of the nitrogen that's in the water, that will help the chips break down, but it means the plants will need some extra because for the first year or two they are sharing nutrients with the chips.  This isn't growth inhibiting, it's just one of those chemistry kind of things we run into when gardening.

If you think the woodchips are a type of wood that termites get into, then be prepared for that to happen, pine and even young redwood (not clear heart redwood, which is pretty rare these days) can definitely get termites.  If it's anywhere near your house, be very careful.

So far I have not found any termites in wood chips.  We use a mixture of mostly Juniper ("Cedar") with some Oak and Elm.  We have so many rotten trees near our house that the termites probably go for those before they go for the chips.

Evergreen is usually pretty acidc. The wood chips should be great for mulching blueberries and any other plants that like acidic soils.  

For other things I would want to have them at least partially composted before using them. If they sit in a pile for a year or two before you use them that might be good.

Okay, thank you.  We live in North Georgia.  I am pretty sure it is not pollen.  It doesn't look anything like it.  It is like a smoky dust when you start shoveling and working with it.  It has been a very hot pile and smoking a lot.  It has been in the low nineties here most days.  Thank you for the tip that it is acidic.  We will definitely keep that in mind.

So the "dust" could be the moldish stuff that happens when the pile is breaking down.  That's normal for composting, but we probably shouldn't breathe it in large quantities.  Paper gardening masks might be a good idea.  And be careful if it's a hot pile, it could be 120 F to 150 F in some places and we really can get burned.

Thank you Cristo.  I was thinking the same thing about using a mask.  Probably the safe thing to do.

We get loads of woodchip delivered - a mix of conifer and deciduous, depending what they guys are cutting. We mostly use it on the paths to keep mud down in winter. It makes a huge difference. In that application, it really doesn't matter at all if it has some allelopathic properties.

Having spread chips directly on growing areas in past years, we now reserve it for certain areas, like the raspberry patch, where it supresses weeds but doesn't impact growth of the berries.

Yes, it's probably mold spores.  You need to be really careful with those wood chips now.  Once they get hot and moldy like that, it's dangerous to breath that stuff.  Believe me: my dear wife had breathing issues for about a month after one big moldy batch where she was breathing that steam all afternoon while we were scooping them up and moving them.

I get 4 to 5 loads of wood chips a year and I move them all by hand (a hay fork and a wheelbarrow).  I'm pretty disciplined now about  moving them as soon as possible.  Once they get moldy, you need to wear a mask and try to work from an up-wind position.  Once you put them on the ground, it's not a big deal -- the wind blows away the worst of whatever is on the surface, and the stuff below is buried.  As long as you aren't kicking those chips up, the mold will quickly do it's job and then go away.  The sun does a nice job of irradiating it.

Any variety of wood chip will mold if it's left in a pile for a week or so (depending on the conditions).  If the wood was particularly wet, it will heat up quicker and will show signs of mold quicker.  It's not usually black mold, which is super toxic, but even white mold is bad enough.  

PLEASE use caution.  It sucks to have wear a mask, but it's not worth a respiratory infection.

I know this post is old, but was looking up what all the white/bluish powderey stuff is in my bark.  I bought a home couple years back and the previous owner put wood chips in the entire front yard; and she had it layed way too thick.
Bark should never be layered more than a few inches.  There were areas that were 12+ inches deep.  I don't even like any bark because it attracts wood roaches over here.  At a previous home that I owned, I had added some bark to a planter boarder, and one evening whilel sitting outside, I saw dozens of wood roaches running out of the bark; creeped me out.  I looked up wood roaches and sure enough they love nesting in bark!   I got rid of the bark that weekend and it got rid of the roach issue; they stayed back to wherever they came from prior to adding the bark.  When I moved into my current house few years back I started replanting the front yard almost the first week I moved in!  I removed most of the bark that was within 15 feet of the house; the front yard is deep.  The stuff that's left is towards the street, and it's very thick in some areas; the previous owner piled it on so high that not much will grow well in it.  Most plants need dirt unless you are planting bulbs!  I've gotten rid of buckets of it.  I put it in the "green" recycle can.  There are a few areas that are still so deep in bark, and it's decaying and it has a lot of bluish-white power.  So I'm not a fan of bark at all anymore!   Instead of adding piles of mulch to keep plants cool, I plant very drought tolerant plants that thrive in heat.  I live in Sacramento, CA.  It gets pretty hot Central Valley, CA.  There's a lot of nice looking evergreen perrenials that thrive in heat; need little water and flower from spring thru late fall.

Welcome to the forum!

Do you have an out of the way corner of the yard where these wood chips might be turned into a compost pile.