DIY - soil improvement project

I have very bad ground .... it was a selfbuild site that was land built up by over 20' back in 30's to become a railway sidings .... what they built it up with is steel works slag & subsoil from nearby A road they were digging through a hill. Disused since 60's it became a SelfBuild site.

For my main veg plots I built up high raised beds and imported soil ... and over a couple of years with loads of manure & sharp sand have got this to good condition and very fertile. But for borders and ground level beds ... although I dug out the 'sub soil' to a depth of 24' and put in imported soil it is very heavy - with high clay content, gets waterlogged.

Due to established plants SWMBO won't let me Rotavate it so mass addition of anything is not an option. I have come up with a plan B

I bought a hand operated 4" diameter Auger ... and have the idea that every 2' or so will bore put a 4" hole around 2' deep and fill it with sharp sand ... and top the last 2" with good loam. Physically tried it and it bores the holes easily. My thought being 2 fold ... vertical drainage will allow (by hydrostatic pressure) water to seep into the sand filled 'tubes' and help drain the ground. and secondly over time the sand will mix in with soil by worm action etc. ,,, and improve the soil.

Anybody see any issues with this ?. And maybe any improvement ?. maybe something other than just sharp sand into the holes ?

Reply to
rick
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This sort of works.

In my case where I had waterlogged clay, I added limestone road bed material, and the grass then grew on top, whilst the water flowed through it

The farm around me is done very very carefully, and features fixed porous land drains at serious subsoil depths, criss crossed by a mole ploughed herringbone pattern that is higher up, and is refreshed every few years.

That's how you REALLY mange waterloging.

So in principle, you need drainage channels of some sort to carry excess water away, and you need ways to get any surface water to those channels effectively. Just raising the surface of course works - the water will flow *under* the flowerbeds instead of through...

But if you want to really drain an area, you need to set up proper drainage of some sort. Wherever the water naturally drains TO, you need to build a system that will get it there faster, and that mains digging down into the subsoil and creating underground water channels, either of pipes or of porous material.

And that's why your vertical bores will only sort of work., They will act as sumps, they will carry surface water undergruund BUT unless they penetrate to an effective drain or aquifer, they wont ultimately get rid of the water.

What WILL works is a trench around the area you want to drain filled with a porous pipe bedded in pea shingle, and back filled. And that pipe must flow down to a soakaway elsewere or a ditch, or whatever is the local drainage system

I have used a pond for this. Bloody great hole, into which pipe flows.

But that was on sloping land.

Oh, a weeping willow will dry an area of soil about 2/3rds of its height, and they grow fast.

Reply to
The Natural Philosopher

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.
Reply to
rick

Soil condition is best built up by food scraps & plant trimmings.

NT

Reply to
tabbypurr

Keep pigs on it for a couple of seasons - works wonders !

Andrew

Reply to
Andrew Mawson

In my case I do not need to increase the fertility - it is fine, just the tilth .. or 'crumb'

Clay for example is usually very fertile plus it holds water - but poor soil condition. My soil is a mixture of clay & silt ... so fertile, but holds water and becomes heavy.

Good quality compost improves both fertility and soil condition, I do add plenty of that to raised beds but can't add to these flower beds due to established plants.

Reply to
rick

In message , rick writes

Re-cycle some plasterboard...

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Reply to
Tim Lamb

So recycling centres now charge for taking plasterboard, because they're not allowed to bury it along with organic matter, because it might release sulphur ... so they separate it then sell it to be used as a soil improver, where presumably it will meet organic matter anyway?

Reply to
Andy Burns

Yup. That sounds about right.

Reply to
The Natural Philosopher

Gypsum - breaks down clay without changing ph - unlike lime.

Reply to
bert

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.

Reply to
Martin Brown

At this time of year, gather up as many dead laves as you can and dig them in. Or better, compost them first. Lawnmower makes a good dead leaf gatherer.

Reply to
harry

You may find that the auger holes just act as sumps and fill with water no matter what you put in them, sand, gravel, whatever. If you drill them down through the clayey layer to something more porous below, then they may drain OK, but I'm not sure there is such a layer from your description.

The best thing to do with heavy soil is loads of organic matter, with some grit or sharp sand. Grit or sharp sand on its own isn't sufficient. Old gardeners' saying: "clay on sand makes land; sand on clay is thrown away". Lime and/or plaster or even chalk will also help to flocculate the clay particles (make them stick together), and give a better-draining crumb structure to the soil. It's basically what's in those 'claybreaker' products you get from garden centres. Oh, and did I mention loads of organic matter? If you spread it around now, several inches thick, worms will take it down over the winter and save you attempting to dig it in and damaging the shrub roots.

Spent mushroom compost is usually treated with chalk or limestone, and will also provide organic matter.

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. Often available in bulk.
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As a bonus you'll probably also get a crop of mushrooms!

But if you've got rhododendrons, azaleas, camellias or summer heathers in the beds, don't use lime/plaster/chalk as it will make the soil alkaline and those plants won't like that.

Reply to
Chris Hogg

I've always wondered - how thick is a the clay layer likely to be (feet, meters, 10's metres?)

Reply to
Tim Watts

Where are you? Some parts of the country, especially in the east, the clay can be many hundreds of feet thick, although around Cambridge the soil can be quite sandy, I believe.

Reply to
Chris Hogg

Found this map:

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The white area running from Norfolk to the Isle of Wight is chalk, the coloured bits are clay of one sort or another.

Reply to
Chris Hogg

Kent/East Sussex border...

Reply to
Tim Watts

Cool - thanks!

In that case I'm probably on the Weald Clay Formation.

Reply to
Tim Watts

There are detailed geological maps online a BGS

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Reply to
DJC

Sounds like The North Downs and The Weald. Quite a mixture depending exactly where you are. Chalk is extensive, but there's also clay (Wealden clay and Wadhurst clay) and sand. Stuff here

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and this
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and the NE edge of this map
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and this
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Wealden clay can be up to 450 metres thick
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. Wadhurst clay isn't so thick
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but you wouldn't be hand-augering through it!

Reply to
Chris Hogg

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