Preparing ground for turf laying
After poisoning a 5 x 4 metre patch of bananas to eradicate, with Round Up, Blackberry Tree Killer and a couple of months later, kerosene, how do I now make the soil o.k. to lay turf to make a nice lawn?
If you used the kerosene to burn the foliage and you think it all burned off, then it is probably mostly gone. If a significant amount of kerosene got on the soil and didn't burn off, though, your soil is now kerosene-contaminated and you will likely have difficulty growing anything on it for years. I don't lnow any way to reverse this other than replacing the soil. This depends on the concentration of kerosene, so you could try planting some grass anyway and see if it grows.
I am not sure what the active ingredient in the blackberry tree killer is, but Roundup should break down in soil over a few months, so by now the Roundup shouldn't be a problem.