Joe Jamies wrote:

Hi,

About 10 cubic metres of fresh fir sawdust was just delivered to my
garden site. The soil is basically clay and very hard to work with. I
would like to use this sawdust to improve the soil structure.

Should I compost the sawdust in a pile (or several piles), or can I
spread the sawdust over my soil so it can compost "in place" (due to
the large amount of sawdust)? As a nitrogen source, I am thinking of
using urea. How long before this soil is ready for planting
vegetables?


Your best bet for soil conditioning is to rototill the sawdust into the
soil rather than just spreading it on top. If you want to compost it you
will have to mix some of the urea into the sawdust, keep it moist and
turned for a few months.

It will compost in place, but since sawdust has a large surface area
(compared to an equal weight of chips or sticks) it will tie up nitrogen
while it is decomposing. You may have trouble with some plants under
these conditions.

If you are direct seeding, watch the seedlings to see whether or not
they are thriving. If transplanting, watch for yellowing leaves that
could signal a nitrogen deficiency. If you see problems, get the soil
tested rather than adding nitrogen blindly. Too much nitrogen can burn
the young plants. You might have to put up with limited productivity
this year.


My vegetable garden will take up half the site, so I would like to
prepare that soil ASAP. I would like to use the other half of the site
for trying other ways of improving soil, eg. cover crops, etc. Can I
start some cover crops now in the area I will not be using for my
vegetable patch? Any suggestions on what a good combination of cover
crops would be?


Depending on where you are, and assuming you can see the soil under the
snow, you can probably seed cover crops now. Most such crops will take
some cold weather.

Clover is good for breaking up soils. Get the field clover, not the low
growing lawn type clover. Buckwheat can be a good summer cover crop, but
don't let it go to seed or you will have it as weeds later. Late in the
summer you might consider oats and hairy vetch. The oats will winter
kill, but the vetch will fix nitrogen and provide some fertilizer as
well as organic soil amendments when you turn it under. Again, don't let
it go to seed.

There may be crops which are particularly well suited to your area. Ask
your state extension service for recommendations. After all, you're
paying them through your taxes, so you might as well get some
information out of them.