Hardcore under flower bed - options
Discussion
Hi,
our new house seems to have a layer of hard core under at least part of a large flower bed. There is about 3 or 4 inches of topsoil and then hard core. Its a big bed and I haven't investigated the whole thing but, looking at old photos suggests that the drive once went over where the bed now is. I'm keen to get a cottage garden style planting going on as it is currently a big empty patch of soil but also eventually want some structure which will mean small trees and bushes.
I could hire a digger, dig up the whole thing and then remove the hard core and fill the hole with a lot of bought earth but this sounds hard and expensive. Alternatively I could buy enough earth and some compost to make it about 8 inches deep and hope that's enough. This sounds easier but pointless if everything will die.
Would tree roots find a way through the hard core? They can mess up roads and houses! Would 8 inches be enough for everything else?
Thanks
our new house seems to have a layer of hard core under at least part of a large flower bed. There is about 3 or 4 inches of topsoil and then hard core. Its a big bed and I haven't investigated the whole thing but, looking at old photos suggests that the drive once went over where the bed now is. I'm keen to get a cottage garden style planting going on as it is currently a big empty patch of soil but also eventually want some structure which will mean small trees and bushes.
I could hire a digger, dig up the whole thing and then remove the hard core and fill the hole with a lot of bought earth but this sounds hard and expensive. Alternatively I could buy enough earth and some compost to make it about 8 inches deep and hope that's enough. This sounds easier but pointless if everything will die.
Would tree roots find a way through the hard core? They can mess up roads and houses! Would 8 inches be enough for everything else?
Thanks
As long as it isn't a soakaway, in ye olde days, they were just a hole full of rubbish.
Loads of plants thrive in a few inches of dirt over rock/stone/rubble, just case of picking the right ones that like good drainage.
MontyDong (or whoever) actually dug in a load of hardcore under a few inches of soil for his Mediterranean herb bed.
Loads of plants thrive in a few inches of dirt over rock/stone/rubble, just case of picking the right ones that like good drainage.
MontyDong (or whoever) actually dug in a load of hardcore under a few inches of soil for his Mediterranean herb bed.
How "hard" is your hardcore? Can you dig though it with a spade? I have a area over an old driveway 2ft deep. At the moment it's only grass and a small Acer, which I expect to root out either side as it gets bigger. I'm not sure I would be comfortable with less than a foot of soil over a large area, but it is difficult to say.
Big things will find their way past it (probably around) and into better ground, but it will limit your options for smaller plants (and those getting established) if it is either particularly dry or poorly drained as a result. Preparing it with more topsoil may well work, but it's hard to say. How much height can you put over it before it is too high?
Seeing as you have a blank slate it is probably worth going the whole way, as a few years of struggling and then having to start over will be even more work.
Otherwise you could go for the Mediterranean cottage garden
Big things will find their way past it (probably around) and into better ground, but it will limit your options for smaller plants (and those getting established) if it is either particularly dry or poorly drained as a result. Preparing it with more topsoil may well work, but it's hard to say. How much height can you put over it before it is too high?
Seeing as you have a blank slate it is probably worth going the whole way, as a few years of struggling and then having to start over will be even more work.
Otherwise you could go for the Mediterranean cottage garden
How big is the flower bed, and how deep does the hardcore go before you reach subsoil?
But to me there's one thing you said that clinches it: you could hire a digger.
Let's just think about that for a moment: you could hire a digger!!
You've got a valid excuse to hire a digger and play with it - why are you even hesitating? You wouldn't even have to make "brumm brummm!" noises - the digger would do that for real!
But to me there's one thing you said that clinches it: you could hire a digger.
Let's just think about that for a moment: you could hire a digger!!
You've got a valid excuse to hire a digger and play with it - why are you even hesitating? You wouldn't even have to make "brumm brummm!" noises - the digger would do that for real!
Mr GrimNasty said:
MontyDong
Edited by Dr Mike Oxgreen on Wednesday 4th March 08:14
Thanks for all the replies. The hard core is pretty firm - you have to dig at it with a fork first. I don't know how thick the layer is - I dug about 6 inches which was enough to plant what I was planting and was still in hard core at that point. I don't think it has very good drainage - it seems pretty impermeable - puddles form fairly easily.
Bed is about 20 m2 but I don't know if it all has hard core under it.
How much depth of soil does grass need?
It looks like I could hire a digger and driver for about £180 or a digger for £100. Plus skip and new top soil so probably get it all done for £500.
Bed is about 20 m2 but I don't know if it all has hard core under it.
How much depth of soil does grass need?
It looks like I could hire a digger and driver for about £180 or a digger for £100. Plus skip and new top soil so probably get it all done for £500.
If water is pooling then I think you've got to get rid of the hardcore. A lawn wants at least 8-10 inches of soil, but your main problem is drainage.
You have two choices to break through the hardcore:
1) Buy a mattock (like a pick-axe but with a chisel-like end - sometimes you get a 2-in-1 tool with a mattock and pick at each end of the blade). This will break up the hardcore, but boy is it going to be hard work!
2) When you hire your digger, get one of those pneumatic stabby attachments (stop me if I get too technical). That will be serious fun!
Forget about a driver. Why pay £80 extra and not get the chance to drive? Sure, a driver will probably do the job in a day whereas it'll probably take you all weekend if you're crap at it, but... digger!!!
Edited to add: If/when you hire a digger, it goes without saying that we need action pictures! Perhaps attach a Go-Pro to the end of the digger's arm and get some video footage.
You have two choices to break through the hardcore:
1) Buy a mattock (like a pick-axe but with a chisel-like end - sometimes you get a 2-in-1 tool with a mattock and pick at each end of the blade). This will break up the hardcore, but boy is it going to be hard work!
2) When you hire your digger, get one of those pneumatic stabby attachments (stop me if I get too technical). That will be serious fun!
Forget about a driver. Why pay £80 extra and not get the chance to drive? Sure, a driver will probably do the job in a day whereas it'll probably take you all weekend if you're crap at it, but... digger!!!
Edited to add: If/when you hire a digger, it goes without saying that we need action pictures! Perhaps attach a Go-Pro to the end of the digger's arm and get some video footage.
Edited by Dr Mike Oxgreen on Wednesday 4th March 10:09
Very busy but want to enjoy digger so will postpone. Think I'm going to scatter seeds on it and see what happens! Maybe use the tool mentioned above to bash any surface pooling and make holes if I transplant anything into the bed but not going to buy expensive anythings 'till I see what happens.
Double digging puts you about 40cm deep so 60cm deep seems excessive. Sounds like you've got clay soil from pooling so I'd dig the hardcore up, and fork in loads of grit manure and compost into the bed to get the clay to break up. You could add some topsoil to it but if you don't add organic matter to the bed, then I'll still be waterlogged.
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