I've recently took over an allotment where the previous owner had not been growing organically. I don't think he used any weed killer just non-organic compost and maybe non-organic manure. He's left a big compost pile which is ready to use but I am not sure whether to use or not as I wish to grow organically. Obviously there may be non-organic fertiliser still in the soil from what he added last spring - but it will breakdown eventually. How long will that take, by the way? I will only be adding organic manure and fish, blood and bone from now on.
Thanks!