Will sawdust turn especially acidic like pine needles do?

[EdwinNJ]

Pine needles - when they fall on the ground and rot, they make it VERY acidic, to the point where that property dominates the ecology of pinelands areas (like in New Jersey and a few other places in the East Coast) - craberries and blueberries are native to these areas because they're one of the only things that can grow in the acidity, and they're still grown in these regions for that reason; there isn't much else place to grow them well. Only other plant you see is Clethra (summersweet) and a few others that can handle the acidity.

OK, so that's pine NEEDLES. What about sawdust, which would also come from pine trees (commercial lumber is all softwood/pine species). Will the wood have the same super-acid effect? Yes yes, all plant material tends to degrade into a more acidic pH, but is it to the same extent as the needles?

I ask because I figure I could get free or cheap sawdust as a mulch

 

[Randy]

I can't say sawdust has the same degree of acidity, but I know it is used as a top dressing by blueberry farmers.

 

[mr_yan]

The type of wood will dictate the ph level. None I know of are as highly acidic as the needles though.

I used to be in super acidic and sandy northern Michigan but have now traded that for the lime stone based old grass lands of Illinois.

I have used saw dust as mulch in my garden. It was a few years ago and I found that the fine dust matted together and created a layer which water would not penetrate. I had to mechanically break it up to save the garden.

A second consequence of sawdust use is the C:N ratio is astronomical and can lead to nitrogen decency depending on how you use it. The available nitrogen will be used by microbes while decomposing the sawdust this nitrogen will then be locked up in the compost for a little while before it becomes bioavailable again.

I have a lot of mixed species sawdust (made with a table saw and router) and have been looking for uses for it. The most recent idea is using it as a growing medium for something like oyster mushrooms.

 

[Randy]

I have some photographs that I took on my friend's farm, but I don't know how to post them since the changes. He grows tons (literally) of blueberries for the market. In one of the photographs there is a pile of sawdust that is used under the blueberry bushes. The pile before they start using it is about 20 feet high and larger than a normal sized house. I don't know from what wood it is, but I suspect either fir or alder. Mark has three very large fields of blueberries and has done well growing them for the market.