Ingredients for new raised beds

[Michele]

I’m just creating a new vegetable garden on heavy clay soil. I’ve previously had an allotment for 15 years on a lovely light but rich loam (Fen soil) and tried no dig for the last 2 years. In my new raised beds I won’t be able to add much top soil from paths or elsewhere in the garden, due to the heavy clay. So I’m planning on using the following mix of composts/manures:

– Spent mushroom compost
– Well rotted horse manure (from horse owners next to my garden)
– Mature leaf mould

I am contemplating whether to order any top soil in addition to the mix above. I was looking at two products available locally:

Denise’s Delight

I see elsewhere Charles advises not to use wood chippings/shavings as they take a long time to decompose. But it looks as it this mix is quite well decomposed already.

or

Dark Fen Soil

Any suggestions on which I should go for? Should I aim to add some top soil to my compost/manure mix?

[Sandra]

Ooh, I don’t know what Charles and the others think but I would tend not to buy in the top soil. I would think the well rotted horse manure, mushroom compost and leaf mould would do fine surely as long as you can get enough of it to build up the depth that you need? I am no expert though, see what the others think.

[Michele]

Thanks Sandra! I need about 3.5m2 of material to fill 8 beds which are 2.4m x 1.2m, to a depth of 15cm. I am making the beds directly on lawn. There are no very woody weeds to get rid of. I was planning to use cardboard, then the compost materials. I think between the mushroom compost (1 cubic m), a very large pile of leaf mould (possibly 2 cubic m, but not all of it decomposed yet) and as much horse manure as I am willing to transport in a wheelbarrow back and forth, I should have enough to fill my beds. I just thought maybe some top soil was needed, as our clay is very grey/blue. See attached photo of a trench in front of our house, dug by the water company!

[charles]

Michele I agree with Sandra, no need for soil.
Compost is much better value too, compared to bought soil which is often very low in microbes, however good its nutrient profile may be.
Your clay will improve over time as worms take the compost down into it, bit by bit.

[Michele]

Thanks Charles that’s very helpful!

[Sandra]

Oh, goodness me, I am glad that I got it right Charles!

[Author]

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