Contaminated soil question

I observed something strange in one of my newly built and spring planted wildflower boxes this year. An area of 2 feet x 2 feet was completely bare even though I kept reseeding and reseeding and reseeding till I finally gave up. Nothing would grow there even the most noxious invasive weeds which I saw start to sprout and then kind of whither away. It was very strange. I initially suspected that a couple of bags of dirt I bought from Menards was contaminated with a chemical like Round Up.
When cleaning the garage the other day I noticed a stain on the floor that had been caused by me leaving this Citrus cleaner in a coffee can. The cleaner is that orange liquid stuff that you can get at Home Depot and smells like oranges but the instructions demand that you wear gloves when using it so it must be pretty corrosive. It was corrosive enough to eat through the bottom of the coffee can, get onto the cement floor, and eat into the cement. I kind of forgot about the coffee can for a month last year until I discovered the mess so the chemicals had a long time to change their molecules. Anyway, right next to this little chemical spill were two extra bags of potting soil that I had stored and I think perhaps made contact with this chemical and might have absorbed a lot of it. When tracing back what happened, I think I remember grabbing those two bags to get rid of them not giving a second thought about the contamination. At that time, in the early spring when I installed these boxes, I was hauling a lot of soil. Each wildflower box takes 25 bags of dirt/compost/peat/whatever.
So this blighted area in the box most likely was my fault. My question to anyone who knows: Will this chemical eventually wash out of the box on its own? My boxes have very good drainage systems. In the fall I need to make a decision whether to extract all the dirt in that area and replace it or just hope the fall and winter precipitation will clean out the dirt. This box is located on my main rooftop making getting dirt up there a lot of effort but I'll do it if necessary.
Here's a pic of the box in question:
http://www.brandylion.com/gallery/Garden2005/121_2157
The bald spot is at the right end.
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It should wash out or at least dilute itself enough over time. How much time? Who knows...till it up regularly so it all gets wet.
But I bet if you used that as a mini compost bin/area that would speed things up. Would need a few handfuls of "real" dirt from downstairs if all you have used so far is bagged clean dirt. Mix in kitchen scraps and crumbled up dried leaves, maybe some grass clippings. Dig in a bowl of kitchen scraps every few days. Even buy a tub of red wigglers from Wal-Mart's sporting goods area (not night crawlers for composting, the small red ones...).
Our family business is building wetlands and all we do is break the soil up 18" getting air and microbes down all the way, flood and replant, and we turn some pretty nasty dirt into some of the best soil and beautiful marshes ever...and in less than a year.
Course a quick fix would be to dig that soil out, dump it someplace away from a stream or water source and replace the dirt but that would be heavier on the back :>)
hth John in Houston

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In article snipped-for-privacy@logontexas.com says...

Thanks for the info. This sounds like a simpler solution than digging out 1/4 of the dirt in that box and even then I might not get all the chemicals because they could have spread. I'll start composting that area today and I do normally water there heavily. This year we're in severe drought here in Chicago. We only got one good rain all year and that was 2 weeks ago and that lasted less than a day making it extremely difficult to keep up with watering. That may have exasperated the problem and I've been having problems with all my wildflower boxes. I feel like I've become a slave to my garden this year -- absolutely no days off! No amount of manual watering can match the power of a good sustained rain or the downpour from a thunderstorm.
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says...

Remember not to plant edibles in that soil, unless you like mysteries.
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In article snipped-for-privacy@hotmail.com says...

I considered moving my hot peppers into that box next year. Luckily I caught this and now that box will be wildflowers for the next few years at least. I'm starting to worry if perhaps some of that dirt made it into my tomato planters since a couple of my tomato plants look like shit this year even though they're producing healthy fruit.
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says...

Could be the chemical, or it could also be that the soil needs beefing up. Buy yourself a soil test kit - one that checks not just pH, but also nutrients. Even so, always assume that yard chemicals (or obviously, cleaning products) are UNsafe until proven otherwise. Since that's impossible to prove without testing them on humans, it's safe to assume that they're UNsafe. :-)
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