Question
Hi,
I recently moved to a house in Oakland, CA that has a yard.  The house itself was redone in the past year but the yard wasn't touched.  It's very warm in this part of Oakland, and INCREDIBLY dry.  When I moved in, the yard consisted mostly of tall, dry grass and then chunks of concrete.  The concrete and the grass have since been removed and all that remains is very dry, dirty soil.  And when I say dirty, I mean there is a lot of litter and trash in the soil.  I would really like to turn this dustbowl into a yard/garden of some sort, and I wanted to know a few things about how I should proceed from here.  First, how much of this dirt (that would certainly kill 95% of any plants rooted in it) should I remove before putting new soil down so I can plant?  And how much new soil should I put down?  Second, I had thought about planting an herb garden and maybe a fruit tree and/or some tomato plants.  Where I live, though, is near many old (no longer in use), but large industrial plants.  Also, I know very little about the history of the house, but I have other concerns re environmental polution in the soil, such as lead paint etc.  Is there any way to salvage or repair the soil so that I could plant herbs or vegetables that are edible?

I appreciate any advice you have!

Answer
Hi Elizabeth, Only a comprehensive soil analysis would reveal any toxins in the soil.  It would be a costly test since you don't really know what to look for, you're just looking.  Since you are concerned, this is what I would do.
First, fix the soil you have where you want to plant ornamentals.  Add leaves, grass clippings, finely ground bark, any organic matter, 2-3" deep and then till it in to a depth of 10-12".  Do not remove soil, just loosen and improve what you have. Rake out any trash.  With a little water, you should be able to grow a nice flower garden and most shrubs.  You may need to dig a little deeper for trees.
For herbs and veggies, build raise beds 8-12" deep and bring in all new soil. No worry about toxins with new soil.
There are many plants (cacti, etc.) that like very dry locations and most of them tolerate very poor soil.  They just need good drainage.  Visit a couple of local independent garden centers.  They are the experts on plants for your area.  They can help design a garden that is very low maintenance, if that's what you want or turn your yard into a tropical paradise...a little more work.
Also talk to your neighbors that have been there a while.  See if they share your concerns over toxins and they may know something about the history of you new place.
The fact that you had dead grass is encouraging.  It probably died from drought, but we know something was growing there.  Jim