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I have a brand new house and garden plot; it is currently sod so I have to dig it this first year and amend the soil. I have run into a section that seems like it used to be a rock path or drive way, just smallish 1"d river rock about five inches down and up to one foot deep, some are big fist sized guys.

I know that "sometimes the problem is the solution," so I am wondering if I really need to pull all of these out and sift the soil? If I don't will they add to my drainage and water storage under the garden? What if they are all mixed into the soil? How deep should they be under the growing strata?

J. Musser
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user3147
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    what do you want to grow where the rocks are? – kevinskio Feb 20 '14 at 15:56
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    you might have found a drain field for a french drain. If so, you want to avoid disturbing it if you can. Ideally, you'd put some weed-block fabric at the top so the soil doesn't wash down into the rocks,. – Joe Feb 21 '14 at 22:29

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There was one time, when I was working in a very good, rich perennial bed, which I had been hired on for three years. The plants loved the organic soil, and showed exceptional pest and drought tolerance. The one day, While I was digging out some peonies, I found a hard, lumpy surface. I dug around a little, and to my astonishment, the majority of the bed, plus quite a bit of lawn, was growing in about 1 1/2' of soil, on top of an extensively cracked, old concrete bed.

I'm not sure what the original purpose of the concrete was, possibly a small parking lot, but I was astonished by how productive the soil was. Of course, I made no effort to remove it.

In your case, I'm thinking it would be wise to leave it in place, and put at least a foot of good topsoil over it. If you want, you could also dig out the rock, but you will be surprised how long and hard that will be. Another option is to hire someone with a dump truck and excavator, to dig it for you.

If the rock is part of a drain system, you don't want to mess with it. If the house is 'brand new', it may be possible to contact the folks who shaped your yard, and ask them.

J. Musser
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Step one is determine the purpose of the stone that is there. As others have mentioned, it could be for a number of reasons. It could be there for no particular reason at all or left over from some previous owner's purpose. It was unclear to me if this was a new house or new to you. It very well might be part of a drainage system - sometimes drainage around a house is pretty challenging if there's not much of a slope to be had - and so digging out the stone would be a big mistake.

That said, depending upon what you're going to grow there, it might not matter much if you leave the rock there. Many plants are quite capable of pushing their roots around/between rocks. You stated that the rock is 5" down or so. If I were planting carrots directly in that soil, particularly long carrot varieties, I'd be more concerned about the rocks than if I were planting, say, strawberries or lettuce or flowers.

Personally, removing rock is a pain and when I can avoid it, I do. Where I'll be digging often, I'm likely to sift would the stone more. But over where my grapes are, I don't bother at all. They won't be affected by the stones in the ground.

I'd deal with the existing sod, add soil - personally I'd add a compost/soil mix - atop the existing soil and opt for a raised bed of some type, assuming you'll be growing annuals or a veggie garden. A good soil/compost mix will cost a bit, assuming you don't have it handy, but save you a lot of headache dealing with that stone. I've found that shoveling soil is way easier than removing rock.

Again, step one is to make sure you understand why the rock is there.

itsmatt
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