How do I get rid of sump oil that was put on garden to kill a banana plant? It is all through the soil and very thick.
It is extremely difficult to remove engine (sump) oil from soil. The website below explains what happens when oil is dumped into soil. If you want to continue use of your garden, you may have to remove the entire area and replace with new soil. This will require digging down into the soil to capture all areas that have been affected. You local garden center can help with specific instructions.