Replacing clay soil

[jobe1972]

Hi I am in the process of removing around a 1ft depth of clay from my front gardens currently they have been covered in stone for years as the ground was always way to water logged to do anything so this year I been removing it . I intend to replace with top soil, sharp sand and compost just need to know what ratio of each before I start filling .. I was going for 1/1/1 ratio but thought would check first

 

[Meadowlark]

Welcome @jobe1972. That's a lot of work/expense depending on the size of the area.

If I was doing it, I would lay about 4 inches of sharp sand (same as shar?) and then fill the remaining space with 1/2 top soil & 1/2 compost mixed.

An alternative approach would be to work with the clay in situ. Remove all rocks, apply liberal amounts of compost, and do that season after season while also turning green manure into the clay. It will become workable and a very good garden soil over time.

 

[redback]

the ground was always way to water logged to do anything so this year I been removing it .

Clay can be good fertile soil. I would make sure it drains to a low point - maybe dig a small pond and ensure there are drainage paths sloping down to that point. You can then spread sand (2" or 50mm thick) evenly across the sloping site and, leaving only paths as sand, top dress the beds with manure or compost (2" thick ). It is probably wise to dig trenches connecting the top dressing to the new sand underlay and plant these trenches out with seed of multiple types. If the seed grow well, you are underway. If the results are poor you need to keep top dressing and planting until the soil becomes fertile and aerated.

 

[Oliver Buckle]

I'm on heavy clay, the garden wasn't cultivated for about 14 years before I came here, but was before that, and the water table is high in wet weather. Dig a large hole and you create a pond, fillit with earth and it becomes a mud wallow, great if you are keeping hippopotamus. It needs to drain. I found one place where someone had put down a lot of shingle, presumably to create drainage, it had sunk and buried itself in the clay underneath, my impression is that sand does the same, silicone is pretty dense.
My solution has been to remove anything resembling top soil, then dig a hole in the clay and fill it with wood, then add compost to the top soil and put it back on top. That creates a bed raised about eight or nine inches and I have been using the clay dug out to make a bank around the edge. There is still a lot of clay in there and as I hoe it creates balls of clay which I hoe to one corner, gather in a bucket, and put in the greenhouse to dry. When I have a bonfire I make sure it can burn good and hot and then add a couple of buckets of clay. It burns to a sort of coarse terracotta that breaks up fairly easily and is much lighter than sand, and mixed with the ash makes a good additive.
The raised beds drain well, and the sodden wood underneath kept them much damper during last year's drought, after five years here I am gradually getting some good quality vegetable beds and a very nice flower bed, I am old enough that I don't go at it hard, little and often, but I am gradually finding other things that help.
For example, there is a 'lady who rides' who lets me collect from her manure heap, I have been collecting manure and chopping it up with poor top soil and am using it to grow potatoes in old compost bags with wood and leaves in the bottom few inches. Having a block of bags stood on it for a few months clears a piece of ground and I have something good to add when I empty them.
Basically I would say, firstly, don't go for a huge amount of work all at once, if it doesn't work it is very discouraging, secondly, having some clay mixed in is a good thing, it hold moisture and nutrients in the small balls of water that collect around the particles, it's having only clay that is a pain.

 

[cpp gardener]

You will be creating a very large bathtub in your front garden. Any change in texture, either coarse to fine or fine to coarse, will impede drainage. The upper layer has to be saturated before water moves into the next layer. It's better to work with what you have.

 

[redback]

Can you tell us @jobe1972 -
1. what is the size of the proposed garden?
2. is there an existing slope on the land?
3. is there a high water table in winter?

 

[Jana]

Hi I am in the process of removing around a 1ft depth of clay from my front gardens currently they have been covered in stone for years as the ground was always way to water logged to do anything so this year I been removing it . I intend to replace with top soil, sharp sand and compost just need to know what ratio of each before I start filling .. I was going for 1/1/1 ratio but thought would check first

I do know that working in lime with the clay soil will help break it down.

 

[cpp gardener]

Nothing will “break down” clay. It is as broken down as it can get. You are MUCH better off working with the clay than trying to remove it or “break it down”.

 

[Jana]

Nothing will “break down” clay. It is as broken down as it can get. You are MUCH better off working with the clay than trying to remove it or “break it down”.

Well, I guess I stand corrected. I got the information from a gardening show on tv.

 

[oneeye]

If you want to dig and move soil, go ahead; however, you don't have to do that. Moving and replacing soil is an extreme labor and a intense project. Your soil is high in sodium if you apply gypsum at a rate of 1 kilo per square meter multiple times a year, you will increase the drainage. Adding gypsum will replace the sodium with calcium and allow the soil aggregates to enlarge for drainage. The best thing when using gypsum the soil ph is unaffected. Post some photos and keep us posted.

 

[Meadowlark]

Well, I guess I stand corrected. I got the information from a gardening show on tv.

You were correct...in context breakdown = to make friable.

 

[cpp gardener]

I suppose it depends on the pH of your soil. We have soil with a high pH and lime would only make that worse, so we add gypsum (thank you Oneeye). If your soil is acidic, it would make sense to add lime to break up the clay.

 

[John miles]

You're absolutely right the pH of the soil is a major factor in deciding whether to use lime or gypsum. Lime does help break up clay, but only if the soil is acidic. In alkaline soils, like you mentioned, adding lime would just raise the pH further and could harm plants. Gypsum is a great alternative in that case since it improves soil structure without affecting pH. It helps with compacted soils too by loosening clay particles and improving drainage. Always good to test the soil first before adding anything

 

[nao57]

One thing you can do... you don't have to haul all that away a foot deep. That could get really expensive. Instead just a couple inches of compost, aged steer fertilizer, wood chips etc. And just every year add a mix of that. That's more affordable. You'll still get results in growing.

You can use trenches and drain areas to keep it from getting swampy.

And I agree with the others that you can get stuff to grow in clay. You just have to cut the clay a bit. The sand idea is also a trick people use when they have clay though they don't only do sand.

 

[Oliver Buckle]

Gypsum is a great alternative

Plasterboard is made of gypsum with a layer of paper either side, give it a good hammering and the gypsum all falls out in little bits. You can find a bit of plasterboard in just about any skip you look in, either the old ones they ripped out or the offcuts from rebuilding. I do like getting stuff for nothing.