Mix me some soil..

[Temp]

I have a flower bed in clay soil but it's had a lot of mature and compost over a decade. I'd like to plant a small  Japanese maple in it so today I dug out a barrel load of soil and filled it with a mix of lawn topsoil, soil improver and composed bark. I thought that would make a reasonably free draining soil but it seems not. I dug a hole in prep for planting but when I put a few inches of water in it the water just sat there so clearly not free draining.

 

Im happy to dig it all out again but are there any experts out there that could recommend a mixture of brand name bagged product I could use to make a free draining mix? 

 

 

[ProDave]

Surely if you are on clay, that is the issue.  You have effectively dug a hole in a watertight sub soil, and put some better soil in, but it does not drain, just as if you had put your good soil in a bucket.

[JohnMo]

We had a clay soil garden and had loads of issues in the end we rotovated tonnes of pea gravel and organic matter. But we also had perforated ducts below the conditioned soil, to take away excess water.

[Radian]

  On 03/07/2023 at 16:54, ProDave said:

Surely if you are on clay, that is the issue.  You have effectively dug a hole in a watertight sub soil, and put some better soil in, but it does not drain, just as if you had put your good soil in a bucket.

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But wouldn't the small test hole that filled with water dissipate into the larger hole and disappear? Sharp sand (grit sand, rendering sand) mixes quite well with soils and improves drainage. But I agree that if all this is contained in clay, it will saturate eventually without some escape route.

[Temp]

  On 03/07/2023 at 16:54, ProDave said:

Surely if you are on clay, that is the issue.  You have effectively dug a hole in a watertight sub soil, and put some better soil in, but it does not drain, just as if you had put your good soil in a bucket.

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Several feet down there is loose hardcore surrounding a drain pipe so if I dig all the way down to that the water dissapears so I don't think I made a sump. I dug out a lot refilled and tested quite a small hole. I think the lawn topsoil I used must have had too much clay in it?

 

Think I'm going try digging out again and trying a mix of sand and ericacous compost. If it becomes too free draining I can always add some of the existing mix back.  

[saveasteading]

A big impermeable hole will hold more water than a small one. The water also has more surface area to shake into, however slowly, especially sideways into the strata.

In time your tree roots will break through to a greater depth and loosen the clay. Or if the first tree drowns  the second one will finish the job.

I freak from experience. Our garden clay is like brick in summer, almost impossible to dig. But it is like plasticine in winter.