My cousin gave me a big garbage bag of sawdust.
How do I make "aged sawdust". I want to use some
in my compost bin and use some for mulch.
I'm not sure what you mean by aged sawdust, but it sounds like sawdust that has been sitting around for a long time. In otehr words, sawdust + time.
I don't think there's any real need to let it age, though. You can use sawdust in compost or as a mulch as is. It's very high in carbon, so in compost, you need to mix a lot of nitrogen.
You can add the sawdust to the compost as a 'brown', mixing it with high-nitrogen 'greens'.
If you use it as a mulch, it will only rob the soil of nitrogen where it actually touches the soil. So, you could get a bag of alfalfa meal and scatter it around where you'll be putting the sawdust, then spread the sawdust over it.
(Alfalfa meal is very expensive at nurseries in those little bags, but much cheaper at feed stores in large bags. If they don't have meal, pellets will do; same stuff, different form.)
For the 'aged' look, just dump it into a pile, water it occasionally, and let it age.
Aged sawdust is sawdust that has been sitting around for some time. Sometimes what I have had laying around will darken in color. However, there is no need to leave that sitting around for any time since you can use it, as I have many time, as a mulch really soon after it is created. Most all sawdust, from wood working shops, comes from wood that is aged so the sawdust is already aged.
I believe "agedÂ sawdust refers to sawdust that has been worked on by fungus etc, not sawdust from old wood.
I have never used it as mulch, have you observed any negative effects?
We've used sawdust as well as fine wood shavings tilled into the garden with no ill effects. Of course we added manure at the same time.
My best suggestion for "aging" sawdust to use as a mulch is to mix it with alfalfa tea, even fresh alfalfa tea, which wil color the sawdust as well as provide needed nitrogen. I've mixed it in our cement mixer but I think you could do it in batches in a 5 gallon bucket.
If you leave a pile of sawdust beside your compost pile/bin you can sprinkle some over each layer of kitchen goodies.
If the sawdust came from walnut or redwood, it will harm other plants. Walnut contains a substance called (?) juglones, which in nature keeps competition down; other plants won't grow. Redwood is the same; in nature, redwood prevents other plants from sprouting near it via a herbicidal substance in its roots/wood.
It's also better if the wood/sawdust has not been treated with arsenic- or copper-containing preservatives.
I'm sure others who've had ongoing wood availability can tell you in more detail how to deal with it. I know as much/little as I do from living in California and from reading widely. Heck, I don't even have regular access to *leaves,* much less wood. (But I do have a redwood tree in/as my back yard, and only agapanthus grows near it. I don't even have dandelions near the redwood.)
You age the sawdust as you would age anything else: let it sit around for a while. Or you can add it to your compost.
The sawdust at the bottom of a sawdust pile, that's been in contact with moist soil, is the part that rots fastest, so mixing some dirt into your sawdust and keeping it moist would speed up the rotting. Might still take months, but not as long in your climate as in ours.