[afcb]

Hi All, first full year coming up and after clearing the plot i filled it with manure from a farm i had worked at. a fair amount of sawdust was mixed in and i've been told this is not good, will it break down before spring?
nice to meet you all !

[Yorkie]

Welcome to the site 

It will eventually break down but might not do so by next spring.  What are you planning on growing where you've put it?

[upthetump]

welcome

mirroring yorkies question, how much is in there and how far have you spread it? can you take it back off and leave it in a pile to break down or have you dug it in?

[afcb]

I haven't decided what to put in there yet, but have probably dug in 1/3 of the plot already. The rest has no sawdust at all

[gavinjconway]

Hi afcb... There are many mixed views on this..

Although most say it's wrong I have grown for years in tubs on my rooftop garden with the same soil / compost.. All I've ever done is added horse manure mixed with shavings, some chicken poo pellets and some fertilizer.. My crops have been brilliant.

Now that my first year on the allotment has just finished I'll tell you what I did..  I added a 4" layer of same horse poo with shavings to the whole plot and dug it in around march and planted a few weeks later and brilliant crops. I'm busy spreading again and will dig in before it freezes over - I hope (I'm still waiting for the manure to be delivered free to the site for all of us to use.)

(If you go to my profile you can find a link to see my web blog where everything I've done is shown)

There are various theories and statements about the sawdust/shavings use up a lot of nitrogen... but also it gives it back once decayed.. so If you have already done it i'd leave it.

[allotmentann]

If you cannot remove it, I don't think it will do any long term harm, other than leach a little nitrogen from the soil. You can counter this by adding grass clippings. Although it may rob some nutrogen, sawdust should break down relatively quickly as the particles are so small. I have been doing a lot of reading on the subject of adding woodchips to soil, trying to get at the truth. Opinions are very varied and it is hard to find real facts and research, but there does seem to be a consensus on sawdust and that is that it will rob some nitrogen from the soil, but as I said if you are aware of that you can counter it. The link below is to one of the most interesting articles that I have found and about halfway down you will see that it mentions the effect of sawdust. (Just seen Gavin has posted something very similar as I was replying!)

http://www.uvm.edu/vtvegandberry/Pubs/Wood%20Chips%20in%20Vegetable%20Production.pdf

[allotmentann]

Also, I forgot to mention that the reason I have been reading up on this, is that I have always kept thick layers of woodchip mulch on my gardens, everything has always grown and the soil has always improved greatly, but I keep being told that woodchips are bad. Personally from all that I have read I don't think so. I understand that sawdust is a different thing but if I had dug it into my plot along with the manure I would not be worrying about it.

[gavinjconway]

Hi lottieann - very interesting article. thanks for finding it.. As my post said I have done it for years and grown great veg... especially as the compost was never changed in about 6 years..

[gremlin]

Hi. I dont think its a mistake. If you dug in 6" of fresh  pure sawdust in every year for many  years, it wouldn't be good.  But once, mixed with manure, no worries.

The same problems would apply to over liming, over manuring, over use of chemical fertilizers, year on year.

[SG6]

I wouldn't worry about it.
You would have to have a lot of sawdust to make any appreciable difference, and being fine it will break down pretty fast and as said we put a lot of wood chip down as mulch and it rots down happily.

To break up a heavy soil I have dug in just about everything, a hell of a lot being wood based and if I had had access to a few bags of saw dust believe me that would have gone in as well.

[ilan]

I also have no problem with using sawdust or wood shavings in a compost mix The biggest problem is the introduction of weed seeds in poorly composted manure

[afcb]

Thanks for all advice, very helpful

[JayG]

Strictly speaking, woody materials do not "rob" nitrogen from the soil - it is "borrowed" from the surroundings to feed the fungi and bacteria which break it down because such materials contain virtually no nitrogen of their own.
It is returned when the fungi and bacteria have done their job and in turn are broken down.

If mixed with manure (a source of nitrogen) the overall borrowing requirement is obviously much reduced - equally, mixing loads of plain sawdust into ordinary soil would not be such a good idea.

(Using as a mulch is not a problem as it can't "suck" nitrogen out of the soil, it just will take longer to break down, which is usually what you want from a mulch anyway, especially a moisture-conserving one.)

[gavinjconway]

Well explained JayG 

[JayG]

Thanks GJC - seems to be a topic I get more than the average amount of practice with!