On 03/12/2016 16:36, rick wrote:

On 03/12/2016 13:37, The Natural Philosopher wrote:
On 03/12/16 13:20, rick wrote:

IN places on site I have dug down about 1.5m installed drainage crates

They help ... but as ground does not drain, not perfect.
Just doing this job now to improve SWMBO flowerbeds.

Just put a dozen holes in about 2' deep and filled with sharp sand
....... while this may not be perfect it may help.

Main thing is improving soil condition ... ground is built up at least
20' ....so no way to dig down to good soil.

Assuming your garden is large enough to have a decent sized compost heap
mulch the beds with 4-6" of compost just before winter and leave the
worms to do all the work digging it in. Failing that spent mushroom
compost isn't a bad alternative (or spent compost from a garden centre).

Your best bet is to make a pond in the most waterlogged part or grow
plants more appropriate to the tricky local conditions. My own soil is a
very heavy clay - the bricks for the house were made from local clay!

Worth asking in uk.rec.gardening for other suggestions of plants and
strategies. Punching through the clay might be one approach if you can
be sure there is a porous layer underneath. The watertable is only a
foot or so below the surface in parts of my garden. My garage pit has to
be drained of water before it is usable.

Clay is very fertile but inclined to waterlog (I have a gradient to
allow the water to drain away). A spring breaks out at the bottom of my
garden after heavy rain. I have ferns and bog plants there now - grass
just wouldn't grow! (I did try improving drainage for a while first)

Although you can buy soil improvers supposed to break down clay by
making it flocculate I have never had much luck with them. Bulky organic
material works but takes time to apply and get results.

--
Regards,
Martin Brown