Re: Raised beds

Careful, careful.  There are many types of clay with numerous 
compositions.  Sand makes my clay more like concrete.  Soil is, 
in large part, ground rock, i.e., sand.  I agree that once clay 
soil is amended with lots of organic material, it becomes great 
stuff. 
 
When I moved here 3 years ago there was overly compacted, 
terribly leached out topsoil no more than 3" deep; home to 
assorted grasses and weeds.  I began to remove the grass almost 
immediately to get the perennial border started.  That's when 
I discovered this property, indeed this entire valley, is 
ancient river bottom.  How did I discover that?  Well, aside 
from research, I couldn't even get into it with the 
heaviest-duty spading fork I've ever seen.  10 HP tiller 
couldn't bite into it.  50 lb. Digging bar, mattock worked 
..sort of.  What I have is a river rock field bound by clay.  
Not an earthworm in sight.  Nary a speck of organic material 
beyond what the sod provided.

Sighing a real deep sigh, I resolved to deal with this.  I 
loosened and opened that entire perennial border with digging 
bar, mattock and spading fork.  I was able to work my way down 
through (what I discovered was) the better clay, about a foot.  
I removed close to 4,000 lbs or so of rock.  Then I called the 
county, bless their hearts.  For a nominal fee they brought the 
most magnificent leaf mold/tree shredded compost I've ever seen. 
I got 8 cubic yards of unbelievably black, rich stuff with 
perfect tilth.  First time through I lay approximately 4" 
and let it sit over the winter.  In the spring, there were all 
manner of earthworms and other good guys, but the soil was still 
way, way too dense and 12" is way too shallow for most 
perennials to be content.

Turns out I have put on about 1/2 again the cubic depth of the 
clay.  What I mean is for each cubic foot of clay, I have added 
1/2 a cubic foot of leaf mold.  What has happened is each time I 
dig to open up a new layer of rock and clay, the organic 
materials work their way down about 4" or so.  I have planted 
quite a bit, knowing that I would have to dig & replant just 
about everything in a while in order to double or triple dig, 
which is my preference for perennials.  But I will also say 
this:  this soil is as gorgeous as any Iowa soil I've seen.   
The clay adds body, minerals and other really good stuff to that 
compost.

Now, an acquaintance in Southern Maryland says that simply does 
not work in their clay.  Another person in the midwest said it 
did.  My best advice is pick an area to experiment in.  Start 
adding organic material only.  Forget peat, it's garbage for 
soil improvement.  Sand .. again I caution caution.  Also, learn 
your soil.  Spend lots of time with it.  dig it and handle it
when it's very wet, when it is terribly dry and everything in 
between.  The more you understand it, the better you will be 
able to deal with it.  Turns out mine is pretty much all finely 
ground ... you guessed it ... rock.  :)   That's why sand 
actually turned it into concrete.   Just add water!

Best of luck.
Jaime

> Hi Barb,
> 
> I agree with Ann B, in that you might consider adding more amendments 
> to your soil. If you have more sand and humus, you might not need as 
> much top soil. It usually doesn't take as much sand to help break up 
> the clay as it does top soil to amend it. Also, you might consider 
> adding gypsum to help. It does wonders to help break up the clay 
> particles, and though it is more expensive than sand, you don't need 
> as much. Clay is actually fairly rich in minerals normally and if it 
> can be kept loose in some way, it can actually be beneficial for 
> plants. I know how it can be compacting and dry with a hardpan crust 
> but compost, sand and gypsum can  greatly help those adverse 
> qualities.. (greensand can also help). 
> 
> Ann B. wrote:
> >I have never had much trouble with plants being close to treated 
> lumber.
> >At least with railroad ties that were treated with creosote. 
> 
> I added this quote just as a reference. While creosote can actually 
> be toxic to the plants, The CCA treated lumber will not really have 
> any affect on the plants. However, my concern would be that a build 
> up of Arsenic in the soil can have an affect on you and the soil life 
> over the long term, especially since it sounds like you will be using 
> alot of the treated lumber. Studies have shown that in playgrounds 
> where equipment built with CCA lumber have had levels of arsenic in 
> the soil around the playground equipment to be at such a level to 
> beable to cause nausea and other adverse conditions in the children 
> that play there frequently. Admittedly we are talking about smaller 
> bodies here but arsenic can build up in the body over a long period 
> of time. Maybe an alternative would be to buy large pine boards and 
> coat with a water seal or maybe using the cedar and somehow butting 
> the ends together firmly with extra support at the junctions. (Trying 
> to brainstorm here.....my brain doesn't seem to storm as much these 
> days though :-)  as I am not any kind of authority.... just a 
> concerned gardener that has tried to read as much as I can. ) 
> 
> I know some of this is environmental but I wondered if it would fit. 
> Hopefully this doesn't create a problem .
> 
> Hope this helps.
> 
> Sincerely,
> 
> Dale Neil
> Zone 5, Rock Island, Ill
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> 
jknoble@warwick.net
NW NJ, zone 6/5
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