Garden ruined thanks to weedkiller

some family idiot has ruined our lawn - Bloody put weedkiller everywhere, and we're left with brown dead patches, as well as weedkiller on the lawn the bright spark also put it on the veg patch where we had wild garlic, mint and coriander

Oh and on the other side we had a plum tree and raspberry tree

Now that the soil is poisoned how long do we need to wait until the ground is "flushed" and we can re grow/eat anything from the garden

Also whats the best way to get the lawn green again