Revamping soggy area of garden

edited 30 November -1 at 1:00AM in Greenfingered MoneySaving
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moneyistooshorttomentionmoneyistooshorttomention
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edited 30 November -1 at 1:00AM in Greenfingered MoneySaving
With the heavy clay soil here creating a drainage problem in an area of my garden I have decided to grow food in, it looks as if my best bet is:

- to have the top layer of soil and clay underneath it removed

- put in a layer for drainage (gravel? shale?)

- put back some new topsoil in a thick enough layer to grow my food in

So my questions are:

1. How deep does this new layer of topsoil on top of the drainage layer (of gravel? shale?) need to be in order to have sufficient depth to it to grow whatever fruit or vegetables I please? I am going to be growing things like grapevines, fruit bushes, etc, on this land and am unsure how much depth of soil these will need for their roots. Would 12" depth be enough?

2. What would be the best thing to use for the "drainage" layer? I'm rather picturing ordinary garden gravel, or do I need something else and, if so, what?

3. Is there anything else I need to take into account in order to be able to just use this bit of my garden exactly as I have decided?
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  • I_have_spokenI_have_spoken
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    Simplest is probably a raised bed, if you dig down into clay soil it'll create a 'sump' which'll fill with water unless you lay in drains to actually carry the water away.
  • DavesnaveDavesnave Forumite
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    I think we visited this matter before with another poster, and my answer remains the same, which is that you cannot drain an area without having a route for the water to get away.

    All you will do is make the water sink more quickly to the base of the layer you have excavated, and there it will sit, unless it has an escape route.

    The area mentioned hasn't been quantified, so it's difficult to be sure what action you might take, but if it's relatively compact, a partial answer might be to go upwards and construct raised beds. They at least could be made to drain, if above the level of surrounding garden.
    People who don't stand for something will fall for anything.
  • edited 2 December 2014 at 9:28PM
    moneyistooshorttomentionmoneyistooshorttomention
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    edited 2 December 2014 at 9:28PM
    I've done some reading-up on the question of raised beds and I don't think its possible to raise the earth up at that point. It could be done one side of the area in question (ie because there is a wall to contain the earth).

    However, at the other side of this bit lies one of my garden paths and any raised earth would come noticeably higher than that level.

    The hard landscaping of my garden I intend to do at some point will be a "one fell swoop" thing of ripping out all existing paths/paving/etc and replacing with something rather nicer-looking and some re-arrangement of the garden and it won't be cheap:(.

    Hence, it wont be peanuts to alter this particular section of my garden (at a very quick guesstimate, without measuring, some 100 square feet or so and its width back to wall is about 5') - but way cheaper than the total garden revamp due at some point.

    Hence, my topsoil on that seems to be only about 3" in depth:eek: and then down to very heavy clay. Hence me planning on just getting a mini-digger in to scoop out down enough depth to just put down a "drainage" layer and then top up with a decent depth of topsoil in line with that garden path (NB: When I do that expensive rearrangement of garden in time to come I will still have a garden path at that point, because it's along one of the exterior walls of my house, so I have to have a path there).

    Its quite a narrow-ish stretch of land and has a land drain along by the wall leading off my plot, so I guess I'm okay for enough drainage between that and a "drainage" layer put down?
  • DavesnaveDavesnave Forumite
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    If you can take a drainage layer directly to a land drain, then that would be good.

    I can't see any reason why a deep bed shouldn't run beside a path, mainly because mine always have! Of course a method of containment is needed, whether it's gravel boards, a concrete block or brick wall, railway sleepers, or whatever. The cheapest, which I've done here, is half round horse rails screwed or nailed to 3" square uprights. Looks better than it sounds.

    I think you'll need more than 12" of soil if it's directly above gravel. Personally, I'd go for 16"- 18", but grapes won't mind if it's shallower than that.
    People who don't stand for something will fall for anything.
  • Well, I guess that's a Plan B sorted then in worst case analysis set-up (ie Plan A doesn't work or costs so much that I'm wincing too heavily to write out a cheque for it).

    Plan C (ie worst case analysis plan) is to think in terms of things like a gunnera manicata plant for instance and an aronia berries plant (as these both like swampy conditions but have an edibility factor).

    One way to look at it is at least a huge type gunnera plant would pretty rapidly make this house/garden look less "conventional" than they currently do and that's a plus in my book, as both house and garden currently look way more conventional than I am personally from the outside and I'm wincing at that...(anyone would think I'm a little old pensioner looking at them outside at the moment....well...I may be little and I may be on a (half) pension but that image is so far from reality that a bit of "shift the picture" would help).

    Crosses fingers and hopes to goodness that gunnera M-- isn't going to become one of those things "everyone and their spouse and dog" has and looking thoroughly conventional by the end of it...as I do like gardens being a bit "wild" and "personal" (part of why I go for permaculture LOL).
  • RASRAS Forumite
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    The other really important thing to work out is "where is this water coming from?"

    It may be that renovating a ditch higher up the hill will remove all the water before it affects this area? Or that you can divert the water as it arrives on your land?

    Or is this coming off a roof?
    The person who has not made a mistake, has made nothing
  • edited 3 December 2014 at 8:39PM
    moneyistooshorttomentionmoneyistooshorttomention
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    edited 3 December 2014 at 8:39PM
    Part of the source of the problem is "Its Wales you know...and rain is one thing there is plenty of here":(

    The drainage that should be there in the hard landscaping is currently missing (no...I don't know why either...considering the house has had several previous owners before me:mad::( and you would have thought one of them would have dealt with it:mad:).

    That is part of the expensive hard landscaping work I will be doing when I have the money for it...ie making sure rain that lands on paths/etc around the house has drains to go down okay, rather than running into my earth.

    The other aspect of the problem though is what the earth itself is like....ie that clay, with downright hard clay not very far at all beneath the surface.

    I have noticed that a lot of gardens in my immediate vicinity have "loads" of hard landscaping, rather than being proper "garden" set-up and am guessing that the clay soil is part of it and possibly another part of it is the Japanese Knotweed that I never even came across before I moved here...but have learnt to recognise a mile off since coming here. Hence part of the reason for lots of cheapie/bog-standard boring paving in many gardens round here I guess, rather than something "nice" and "garden-like".

    I'm sticking to its going to have to be "nice" and "garden-like" personally...hence a very sorry-looking bank account making it be what I personally recognise as being a garden:(.

    The water coming off the roof of my own house is (should be!) getting caught in my waterbutts, but the thing is there is still one heck of a lot of rain going on here that needs somewhere to go at present.

    The neighbourhood norm of cheap paving stones/gravel/tarmac for the "high priority here parking of cars"/soggy mossy grass is not an option for me personally, as I'm quite homesick enough without the proper garden that is part of what I moved for. Hauls out chequebook again/examines bank statement/sighs and gets on with it...:cool:. That's the thing for me personally....it has GOT to be a "Home Area" style garden....
  • I_have_spokenI_have_spoken
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    There's no shortcuts when dealing with clay soil in an area of high rainfall, just get digging and lay in the field drains...

    d155b9d9a849be586fadbcfe75be9dec_zpsedb85d7f.jpg
  • Hi,
    Have read the forums for a while, only posting here because we had a similar issue when I was a child. The day we had moved into our house the garden was literally a lake, but after some pits were dug, the water drained back into the earth.


    My mum (with help of friends) dug three deep pits in the garden, about 4ft-5ft wide and about 5ft-6ft deep, they dug until past the clay layer, then the pits were filled with hard core. By breaking through the clay layer, the water was able drain away.


    I remember that they also built up the height of the garden a bit too with topsoil by a couple of inches, before laying new lawn. The number of pits depends on the size of your garden. Ours was about 25ft x 50ft (I think).
  • DavesnaveDavesnave Forumite
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    I think the heavy use of hard landscaping in West Wales is more down to tradition, since it was even more prevalent in my relatives' area than yours, and they had no great problem with clay.

    As Magic Cat says, a hard pan beneath clay can sometimes be broken through, but it depends how deep the clay goes. I've had a couple of 8' deep pits dug recently in my field, looking for a rock seam, and in one, the clay layer bottomed-out into rock at around 7'. Good luck if it's like that!

    There's two ways to look at an area of difficult garden. One is to throw money at it, and the other is to concentrate scarce energy and £ on areas which are more productive, making them even more so. I wouldn't necessarily abandon your wet area, but I'd get on with the rest first.
    People who don't stand for something will fall for anything.
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