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Heavy clay soils
chicken chaser
Posts: 147
I'm currently digging out what could be described as an island bed. Its flat with the lawn and I've removed the turf from the top however, about 3 inches below this particular area, the soil is heavy clay and a completely blue clay to a double spades depth.
I've set aside the topsoil and would like to remove some of the subsoil before replacing it with compost, manure and graded topsoil to increase the topsoil depth before planting.
It may be a daft question but I seem to read everywhere that it just needs organic matter to it. Nowhere does it say remove any, but I don't want to add a load of muck and compost and increase the amount of matter inside of the bed. Is it OK to remove the subsoil to allow space for the good stuff?
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Hi Chicken chaser, We did a similar thing in our garden a few years back. We have heavy clay soil too. After taking up the turf we roughly dug the soil to loosen it and then added roughly a big bag of rotted horse manure and some leaf mold to each sq mtr of soil. You can either dig this in or let the worms do the hard work in taking it down into the soil,therefore improving the condition of it. The bed may look high to start with but it will soon sink down.
However much compost I put on my clay soil, it disappears and the level soon sinks again. I think it's doing the earth good though.
Some years ago a friend who had a farm in the fen country told me to lighten & improve clay soil use horse manure with plenty of straw. To improve light sandy soil use com manure. Also my brother in law had a back garden that was a blue marl clay and virtually unworkable when he moved in. Through sheer hard work, digging, re-digging and adding coarse sand and sewage sludge he managed to turn the clay into a very acceptable soil that produced good crops of vegetables.
Most of the gardens I look after are on clay. Get as much well rotted manure as you can get your hands on, I'm lucky I have access to literally tons of the stuff for free, and lay it on thick as you can. A bag a square metre as said previously is ok although I lay it on even heavier in some gardens. Right now is fine, although I do it twice, once in October/November and again right about now. It takes a year or two to get a reasonable soil, but by the time you've done it you'll have lovely soil to work in.
If the clay is really heavy, break up the surface and add grit as well.
I have a source of manure which is free but its a pain to access and its probably full of weed seeds! Its well rotted but the top of it was growing weeds. I took the stuff from the bottom of the pile which was as black as tar.
I've bought 4 large bags of manure and 4 bags of compost to start it off. The space is 8ftx8ft square.
I have begun digging some of the solid blue clay out of the bed, purely because I have spare screened topsoil which is going to waste at the moment so rather lose good soil (some with turves) I'd rather move some of the clay. I'm planning on planting in the space in April/May time so would like to get it fairly workable.
Wouldn't worry about weed seeds, you'll be burying them on top of the clay with the decent soil on top. If you are digging out the clay, double the amount of manure your'e putting in. The top soil you can put on top, it'll speed up the break down.
I'll leave it for about 6 weeks now before I look to plant into it. There were plenty of worms ready to get to work on it all!