Hi, we have an above-ground vegetable garden built by the previous owners. When we bought the house 1 year ago, the vegetables were growing well. We tried running greywater but my wife forgot and stain remover ended up in the soil, which killed some of the plants. Since then, plants haven't grown very well at all - although I tested the pH a while back, and it seemed fine. We now want to dismantle the garden bed and relocate the soil, but we're not sure if it is any good. As I've been digging down through it (the bed is almost 1 metre deep) its clear that there have ben many generations of gardens there, with different soils added. Also many roots coming up, we suspect from a nearby Celtis tree. The borders of the garden bed are lined with weed mat which lets some water through, but around the edges the soil has a white substance caking it - which I think maybe greywater contamination. Long story short - what tests can we do to see if this soil is good for using elsewhere (for shrubs etc). Is there a danger that the soil will 'poison' whereever we put it? I am new to gardening and know very little about soil contamination.