"JB" wrote in message
...
On Wed, 20 Jul 2005 12:13:39 +0100, Kay
wrote:

In article , H Ryder
writes
My soil is compacted clay, with hardly any worms. Have decided to try
double
digging the borders. Is this a good idea?

Probably not. The clay you have at the surface is as nothing to the clay
you'll have two spits down.

What should I dig in - I've got
some sharp sand and compost. Will this do - I can't really afford grit
.
Would appreciate any advice

Also what is the best technique for actually breaking up the great, hard
lumps.

A pickaxe.

Hitting them with a spade just seems to make them harder! TIA,


Spread a 6 inch deep layer of compost over your borders. Worm activity
will incorporate the compost into the soil (they're fast breeders, and
even though you don't have many to start with, you soon will once you
start spreading compost).

Meanwhile start a compost heap if you don't already have one, and
continue spreading 6 inch of compost each year.

This will be more effective than trying to improve the soil by a once-
off digging in of compost and sharp sand.

I have a clay soil and found double digging to help greatly. You're
right that two spits down it really is quite disgustingly pure clay.
But as long as you don't mix the top soil, such as you have, and sub
soil then it will greatly improve drainage. Easier that pure double
digging is to single dig but while each row is dug out then use a fork
to loosen the soil at two spits depth and then return the top soil.

The biggest benefit however is just to add 'organic matter' in
quantity. You should be adding a layer of horse or farmyard manure
over the top. Although you say you have hardly any worms they will
soon arrive and breed and do mst of the work for you but you can give
everything a head start by single or double digging first. Manure is
cheaper than bought compost (but don't expect your OH to thank you if
you use her car to fetch it) but cheapest is to start your own compost
heap.

Digging before winter and leaving it exposed to frost will help to
break it up.

Gypsum is cheaper than proprietary clay breaker compounds and does the
same thing.

Any other suggestions

A lot of good ideas have been mentioned already. Allegedly lime at 1lb/sq.yd
will help break up the clay, probably best scattered on in autumn. Gypsum
apparently does the same job without raising the alkalinity of the soil.
As to breaking up lumps I found that, as another poster mentioned, the
weather has
to be right: too wet and it sticks together like s**t, too dry and the lumps
are like iron.
If you can't wait for the frost to break it down, I found that a rapid
up-and-down slicing
movement with a spade is more efective than whacking lumps with the back of
the
spade.
Otherwise lots and lots of organic matter. Apparently horticultural grit
needs to be
applied in rather large quantities to have any real effect, if you were
thinking of going
that route.

Andy.