I looked up more on Roundup Plus - I didn't realixe there are so many different formulations. Maybe what jBaker used was "Roundup Concentrate Plus" which adds 0.73% diquat dibromide to cause faster burn down or the weed. Based on the following, I personally wouldn't worry about it. It bonds so strongly to soil that plants don't absorb it and it will not wash away or breakdown. Those passionate about organics will read this differently, but you wouldn't have bought the product if you were passionately organic. I expect those who view all non-organics as poisons would want to scrape off the top inch of soil that might be contaminated and throw it away, as it will never go away otherwise. Here's some info on diquat dibromide: ENVIRONMENTAL FATE Breakdown of Chemical in Soil and Groundwater When diquat dibromide comes in contact with soil, it becomes strongly adsorbed to clay particles or organic matter in the soil for long periods of time (Koc - 100,000 g/ml). The strong chemical bonds formed by diquat adsorption to soil particles make the herbicide biologically and chemically inactive. That is, in certain soils it is unlikely to be: carried away, or leached, by water seeping through the soil; taken up by plants; broken down by microbes in the soil in a process called microbial degradation; or broken down by sunlight (photochemical degradation). Traces, or residues, of diquat have been found to persist in soil for many years with very little degradation (8, 21, 32, 36, 40). Soil capacity for adsorption of diquat is so high in comparison to the rates at which it is applied that there is little possibility that leaching or groundwater contamination will occur. Field and laboratory tests show that diquat usually remains in the top inch of soil for long periods of time after it is applied (31, 32). However, there is also evidence that diquat has the ability to eventually use up, or saturate, all the available adsorption sites on soil clay particles. Groundwater quality can be affected if soil adsorption sites become totally saturated because water moving down through the soil can carry any non adsorbed herbicide into the groundwater. More research is needed for a better understanding of the potential effects on groundwater of long- term, repeated use of diquat. Studies on the erosion of diquat-treated soils near bodies of water indicate that diquat stays bonded to soil particles, remaining biologically inactive in surface waters, such as lakes, rivers and ponds Here is a link that might be useful: Cornell - Extension Toxicology Network

what they all said ... good work on using the phone ... etc ... but i dont know if your comment about them 'soaking it up' is realistic .... would welcome a discussion on such ... regardless.. i suspect you are never going to get over this .. lol .. so may as well chuck it all in.. just for piece of mind ... its not the first time a farmer lost a crop ... ken ps: sos must have GIANT slugs .. lol ... there must be an attractant in such.. so something was attracted ... wouldnt surprise me if it isnt some beer byproduct ... maybe used yeast??? .. who knows ...

I have no business here, since I was just searching the forums for threads on lasagne gardening, but I just have to interject a comment!! Catnip, you are SOOOO lucky your boyfriend shares your love of gardening!!! My boyfriend (who I love dearly) doesn't. He isn't against it, but isn't overjoyed at the thought of spending time on his knees in the yard up to his elbows in soil with his butt sticking up in the air, as I am. He drops me off at the Nursery to browse and comes back for me later to help me haul my purchases home. I'm not complaining, mind you, but I would love it if he wanted to help me build a compost pile or had something he really, really wanted to try growing this year. Even if he got interested all of a sudden and started telling me I was doing it all wrong, I'd just laugh at him and hand him a trowel. So count your blessings, young lady!! :-)

If you want to do a soil test at home, there are kits available. It's not as accurate as those run in a lab, but results are usually in the ballpark. If you don't see kits in any of your local garden centers, then order one online. It certainly is a mysterious problem, and I hope you will follow up with how your next planting fares ... and the cause, if it ever is discovered.