Sawdust.

[beeman]

I have discovered a source of composted sawdust, as much as I want or need. Before I go overboard, filling my garden with this free bonanza, I need some advice.
I know one needs to add extra nitrogen to accommodate sawdust, but the question has to be. How much to add?
I suppose the real answer would be to 'soil test' then add? When, now or in the spring ready for planting?
Any suggestions?
Regards beeman.
PS. If you have a sawmill close by, give them a visit, they just want to 'get rid' of the stuff.

[sunkeeper]

This was taken from the link I posted. Sunkeeper

On the surface it would appear to be a great substitute. However, fresh sawdust right off the saw can be very acidic depending on the type of wood being used. A good rule of thumb, if you decide to purchase the sawdust, is to pile it where it will be undisturbed and let it sit one year. The rains and natural decomposition will leach out most of the acid and then it can be used for mulch the next few years. Or of course, simply use “regular” mulch!
Take care, however, to use sawdust primarily as a mulch for acid-loving plants, such as azaleas, rhododendron, heathers, evergreens, potatoes, and rhubarb. Sawdust has an acidifying effect on the soil as it breaks down

http://www.landsteward.com/page.cfm/65550

[beeman]

This stuff has to be at least 30 years old and well rotted, so I don't think your suggestions should be a problem.
I still need to know how much nitrogen is necessary.
Regards beeman

[sunkeeper]

SAWDUST is a source of carbon and requires additional nitrogen to break down. A little on your garden won't hurt but if you try to mulch with it you will need to consider whether your soil is rich enough to supply the necessary nitrogen to break it down. If you add green manures or grass clippings to it the plants will get by, but it is a judgment call. Even in a compost heap it needs to be layered with nitrogen-rich materials. It is somewhat like oat bran, useful but only in moderation and not very nutritive in and of itself. Be careful about sawdust made from plywood or treated wood. Know your source.


http://rch.my.cape.com/FERT.HTML

[Mervyn]

It was my understanding that rotting process of sawdust (and wood for that matter) is what drained the nitrogen , but if it is already fully rotted, I didn't think it would still drain the nitrogen . . .

[butterfly]

There is a lumbermill 1 km from me

Sawdust is excellent to use as long as it is rotted 2 yrd old

I pay $25.00 a 1/2 ton truck load

One year my cuz and I got into an old mill her father had years ago

The sawdust was at least 30 yr old. WE sure had great gardens that year.

But don't use fresh bark mulch like I did one year.

I did this after I planted 25 delphinines among at least 50 other plants. Everything died from the toxins of fresh bark

That was about 15 years ago when bark was just starting to be used and no one told me about the toxins. I was furious when I saw all the plants dead

[Durgan]

I have discovered a source of composted sawdust, as much as I want or need. Before I go overboard, filling my garden with this free bonanza, I need some advice.
I know one needs to add extra nitrogen to accommodate sawdust, but the question has to be. How much to add?
I suppose the real answer would be to 'soil test' then add? When, now or in the spring ready for planting?
Any suggestions?
Regards beeman.
PS. If you have a sawmill close by, give them a visit, they just want to 'get rid' of the stuff.

Usually one uses what is readily available. I use city supplied wood chips for mulch and often work some into the soil for aeration, and find no problem with lack of nitrogen for plants. If of concern some urea mixed in with the sawdust when spreading might be beneficial. Also too much nitrogen is probably as bad as too little.

If composted sawdust were available I would certainly be using it with little concern, certainly in a small garden. It might be an issue if you were growing a large field of one crop for market gardening.