On 9/25/2017 11:30 AM, mattyvx wrote:
Hi all been working on a new garden project, new garden is clay and
wet!

I rotavated and amended the lawn area several weeks ago and turf is
growing and rooting great however I decided to dig over the beds with a
view to remove the substantial builders rubble and heaviest clay lumps

Bed is around 1.5mx9m by around 300/350mm deep

After some rain last night I came down to find the empty end of bed FULL
of water like a bathtub the full 350mm deep 24hrs after raining, must be
seeping in from other parts given it's now the lowest part.

What should I do? The worst bit is the empty part so as there is no
resistance there water is flooding im but what if i follow my original
plan to level out the remaining clay soil and mix it back into the bed
with 1-2 tonne compost?

Or...

Am I doomed here now and need drainage solution to reroute which is not
ideal


Apply a generous amount of gypsum (calcium sulfate) over your entire
garden. A layer 1-2 cm would be about correct for a start. Lightly wet
it down so that the wind does not disperse it. If you get some rain,
that would be good because it needs to be dissolved and rinsed into the
soil. Without rain, you need to lightly water it about once every three
days until you do not see it. Repeat this treatment once over your
entire garden. Then repeat it at least two more times in the areas that
tend to have the worst drainage.

Gypsum reacts chemically with clay, making it granular and porous. That
improves drainage. Unfortunately, you might have to give another
treatment at least annually.

Another thing to consider is adding peat moss when you "rotavate" (which
we call "rototill" in the U.S.). Unlike many other organic amendments,
peat moss decomposes very slowly. For your worst soil, try tilling
about a 15 cm layer of peat moss to a depth of 30 cm.

DO NOT add sand to your clay. Adding sand to clay is equivalent to
adding gravel to cement to make concrete.

In the end, you might have to make a dry well at the lowest end of your
garden.

--
David E. Ross
Climate: California Mediterranean, see
http://www.rossde.com/garden/climate.html
Gardening diary at http://www.rossde.com/garden/diary