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Replacing old soil in borders

Hi everyone.

I've lived in this current house for a couple of years and the soil is really, really bad. It's very heavy clay, which waterlogs in the winter and cracks and sets like concrete in the summer. It is nutrient deficient, even bulbs come out tiny and stunted and look pathetic.

I've tried numerous ways of fixing this with mixed results, but I've decided the best course of action will be to get rid of all the existing soil in the border to the depth of around a foot.

I was thinking of bulk-buying some well rotten manure, topsoil and sand and sort of mixing it all together in a wheelbarrow and starting completely from fresh.

Does this sound like a good idea? I'm trying to stay away from just adding and adding and adding more material as I've been doing that for two years and it's not getting into the clay below and I'd like at least a couple of beds I'll be able to grow something in this year.

If anyone has any other suggestions or ideas to make my life easier, I'm all ears!


  • LoxleyLoxley Posts: 4,453
    Before we start, what have you done so far that hasn't succeeded?
  • archerm1archerm1 Posts: 13
    I've tried digging in leaf litter and manure, with added sand. I had to take out the clay in chunks and smash it all up, mix it together and put it back in.

    I had some success but the depth of workable soil was quite shallow and it was back-breaking. Even in the one border where this worked, there are still errant lumps of clay I've missed. Garden is quite big (for me) so it would take years to get the whole thing workable using that method alone
  • ObelixxObelixx Vendée, Western FrancePosts: 27,600
    Clay soil is usually fertile - full of minerals - but sometimes so solid many plants can't get them and, as you say, water-logged in winter then bakes like bricks in summer.

    The best treatment for clay is to pile on thick layers of well-rotted manure every autumn and leave it over winter for the worms and other soil organisms to work in.  Make the layers several inches thick and add any fallen leaves you  can gather and any well-totted garden compost.

    It won't be a quick fix but it will be worth it and you'll end up with the best soil.   You can start now in areas where you have no plants or plants that can be lifted and re-planted after the mulch has been laid but keep the mulch away from direct contact with the trunks of any trees and shrubs as it can make them rot if piled up too close.   Their roots will love it tho.
    "We don't stop playing because we grow old; we grow old because we stop playing." - George Bernard Shaw
  • archerm1archerm1 Posts: 13
    Ah I forgot to mention the whole place was lined with conifers which I think removed all the nutrients!

    Because I'd heard that about the clay soil before. I smashed up a few feet of it almost to sand and it was pretty poor in terms of what grew
  • LoxleyLoxley Posts: 4,453
    I agree with Obelixx, clay soil is usually fertile; it's the soil structure that is the problem. Also agree with the idea of piling on thick mulches over successive years. As a quick fix now though, you could add a layer of topsoil and compost, say 150mm, on top of the clay soil (after you have gone over it again to break down any large clumps). 150mm depth is going to be OK to get plants roots started, will be better drained than the underlying clay soil, and of course plants will still be able to root down into the underlying clay as well. 
  • Allotment BoyAllotment Boy North London Posts: 5,004
    I agree with @Obelixx, the best method for you would be a no dig approach.  Look up Charles Dowding,  although he is a market gardener and mostly grows veg and salad crops his methods  will work for ornamental plants too. Thick layers of compost 5-10cms every Autumn and plant direct into it. The worms will work it in . It will take time, maybe grow annuals and herbaceous plants only for the first couple of years. I know you would normally start with shrubs etc for structure but it will be hard to get them in with the soil you describe. 
    AB Still learning

  • archerm1archerm1 Posts: 13
    Thanks for the advice.

    I'll add some topsoil and manure and see what it's like over the course of the year.
    Any ideas for what to start with? Quite a sunny garden, although NE England so take that with a pinch of salt.

    Have some QE hedge roses which are not flourishing, hoping to widen the borders at some point and plant a laurel hedge, but some simple ideas for this year would be nice.

  • TheGreenManTheGreenMan Tyne & Wear Green Belt Posts: 1,550
    It depends what you’re looking for while you wait for the soil structure to improve. 

    I’ve moved into a house recently (also NE and clay soil) and the back garden is mainly gravel so the clay has been compacted and covered for many years. 

    I’ve started making beds and filling them with manure, compost, leaf litter etc. I started one patch last summer and the soil is now good enough to plant some things in it. I did dig. A lot. Turned it over, broke it up, mixed in composted manure, compost, old spent potting compost then laid a thick layer of manure on top. 

    I posted the other day about a lupin I’d thrown into the ground in another part of the garden which I haven’t started conditioning yet and it’s thriving. 

    Lots of online plant sellers let you filter my soil type and sun level. Have a look and start a list. Even if you’ve just got a foot of better soil on the top you can still have some things growing while you wait for the critters to do their thing and start to take the goodness further down. Just don’t buy anything expensive in case it doesn’t survive. You could always take out anything that looks iffy and pot it up. 

    The one thing I’ve learned in the last year is that patience is key. Patience and lots of organic matter. 👍🏼
  • FairygirlFairygirl west central ScotlandPosts: 46,325
    I'd echo what has been said re adding manure. Conifers do take out a lot of the main benefits from soil, but it isn't forever. If you can add loads of manure, it will soon improve. That's the most beneficial product to add.
    The amount of conifers that were there, and the size of the borders are factors, so it's impossible to advise re any planting without knowing the kind of area you have to work with, and the aspect. Some photos will help too  :)

    Forget sand - that can cause more problems than it ever solves if it's the wrong type. 
    It's a place where beautiful isn't enough of a word....

  • PosyPosy Isle of Wight.Posts: 3,219
    My soil was just like that and I very respectfully disagree with @Obelixx and many of the above contributors. That sort of clay is not full of nutrients waiting to be released by piling on manure. It is solid and lifeless and probably doesn't have worms to process all the muck. No dig methods will work but only over thirty to forty years.

    So what should you do? First, check the water table and drainage. Dig a hole bout 18" deep. Does it fill up with water? If it doesn't, pour in a bucket. How long before it all drains away? If the drainage is poor, replacing the soil will only create a place into which the wet drains and your plants will drown. I believe it's called a sump. In this case you need to build up the level of the borders to allow plants to grow with their feet in draining soil. Some people make raised beds but you don't have to go that far unless you want to.

    If the drainage isn't bad you can improve the soil by adding muck and possibly coarse grit - NOT sand of any type - but if you want to improve things in your lifetime, dig it in, break up the clay and mix it all well. Mulch as often as you can in following years.

    It is back-breaking, so do a section at a time and think of it as a workout. It takes time to do a job properly, but it's worth it in the long run.

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