SLC
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How High Should A Rasied Garden Be On "Marsh Land?"

So after last year's garden was pretty much a disaster because all it did was rain, and then on top of that, I discovered our house is built on marsh lands, so my garden was a swamp. It would not drain and it was ankle high in water.

So I think I need a raised garden to help with that. My question is how high should I make it.....on top of the "swamp?" What is enough to drain?

Any advice is welcome!

cynthia_h
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Are you trying to raise your ground level, or are you thinking of building raised beds? One is an engineering problem; the other is a straight-forward gardening situation.

Cynthia H.
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SLC
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If I am understanding your question correctly, I am trying to put a raised bed above the ground. I bought retaining wall blocks and we are going to put them around the garden I had last year and then fill it with top soil, which HAS to be better than what we have now for dirt. I am hoping it will actually drain. But how high should I raise it up? Like, how many inches of top soil should I add so it will drain?

Do you know what I mean? I might not be explaining myself correctly.

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rainbowgardener
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Yes, I get it. We often recommend raised beds for dealing with a variety of soil problems. I would think you want them deeper than typical. I have raised beds sitting on my concrete patio (ultimate soil problem - none!) and they are 18" deep. I grow tomatoes and anything I want in them. That would be my suggestion for you.
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applestar
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I was going to say 18" for soil depth as well. This may mean building a raised bed that is at least 20" or more.

SLC
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Oh good, I am so glad I asked, because I was only thinking of doing 12 inches because I still need to step up into the garden and I was thinking anything higher might be difficult. So now that I know, I will have to work on making some kind of steps or something into it. It is going to be a permanent fixutre in the backyard, and the bricks and soil are going to cost me a lot of $$$ so I want to do it right the first time!

The only thing is, the blocks are 4 inches high, with 2 inches going into the ground and a cap which is 2 inches high, so that would only bring it up to 16 inches high. Is that okay or does it have to be the full 18 inches?

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applestar
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Although this would mean more blocks, I think you are better off building series of 3-4' wide raised beds which you would reach into and tend from the ground level rather than stepping up and into the beds, compacting down the soil. The width will depend on how long your arms are. I built 4' wide beds and am finding that I'm a tad too short to reach the middle from either side. :roll:

I think 16" high beds will only have 14" or less soil depth to the flooded ground level....

You could also consider building the sides of the raised beds out of lumber or timber and using the blocks for more decorative element -- or maybe just for the bottom courses. Rainbowgardener's raised beds are really nice.

SLC
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Thank you for your input. The problem is, this is my boyfriend's house, and I am lucky he is even letting me have a garden at all, so I can only have what he is willing to give me. I would love, love, love to have 2 thin, long beds, and I even asked him to do that, but he won't do it. So I have to take what he'll give me, which is why it is wide; therefore, I have to step into it. And he wants it to look as nice as possible, hence the retaining wall blocks. So, I'll make it work.

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