Soil!

[SchrodingersHat]

We moved house last year into a newish build that is about 6 years old. I'm now looking forward to starting work on the garden (only grass there at the moment) however the soil is terrible quality so I need to improve it before getting to the fun part where I can buy plants.

From what I've seen the topsoil is only 3-4 inches deep in places, the soil itself seems to contain quite a lot of clay plus loads of stones, building rubble, etc.

What's the best way to improve it? Dig out the topsoil and remove a layer of subsoil and all the stones, then replace with more topsoil/compost? If so how deep should the topsoil be? Or can I get away with just digging lots of compost into the subsoil? What type of compost? Any other hints and tips?

Thanks in advance

[ComeIntoTheGardenMaud]

If you have got the time and strength it would certainly be a good idea to get rid of all the builders' rubble. It is possible that the building work has brought the clay subsoil closer to the surface. If you can pick out the biggest lumps of clay and dispose of them, it'll help. If you haven't got the appetite for lots of digging, you might get away with just adding a very thick layer of organic material (manure compost, spent mushroom compost etc) and letting the worms do the work of taking it down into the soil.

If you're removing turf, you can stack it grass side down and let it rot - it makes an excellent soil improver.

[SchrodingersHat]

Thanks, the garden is raised above the house (same as all the other houses on the close) so I suspect the builders dumped a lot of soil/rubble there when they dug the foundations for the house.

I'll make a start on getting rid of the clay/rubble. It will take a ling time but it will be worth it in the long run I'm sure - and much easier before we put any plants in. I've already started flipping the turf that I've taken up.

When you say a thick layer of compost, etc. how thick do you mean? I'm just trying to work out how much I will need to buy.

[ComeIntoTheGardenMaud]

Well, I'm often a bit stingy with mulching because I can only fit so many sacks in the car, but I think the advice is usually to add about four inches. If you watch last week's Gardeners World on iPlayer, the very last bit is the divine Monty mulching part of his garden. Very instructive.

[CraftyBec]

I live in a newish-build house too (about 5 years old). The soil in the garden isn't too bad, quite heavy clay but clay is quite good for nutrients I believe. My garden is also slightly raised at the back of the house, and it has settled over time so the lawn is not very level. It should have been terraced really.

I had some of the lawn dug up to put in a border, and did exactly as Maud says - put the turf on the border grass-side down, and allowed it to rot down. Think I added a bit of manure as well, you need to deprive the grass of light or it won't die. Now plants seem to be growing fine - as much as they can in a small north-facing garden with high walls .