My dog is urinating on my lawn and it is discolouring the grass, what can I do to stop this and how can I repair the damage?
The only true way to prevent this is to train the dog to urinate somewhere else. The chemicals in animal urine (dog, fox, badger) will change the appearance of a lawn. If the event is witnessed then the area concerned can be washed down with plenty of plain water; diluting the chemicals to prevent any major damage.
A poorly fed lawn will show urination spots as lush, dark green, quick growing patches. In a well fed lawn the animal urine will cause brown patches where the turf looks dead and perhaps a dark green surrounding edge. If you have lush, dark green patches these need to be systematically mown down to the height of the rest of the lawn; and the lawn needs to be given a high quality feed. Brown patches need to be raked to remove dead fibres, then overseeded, using a 50/50 soil/lawn seed mix or alternatively scorched areas can be repaired by replacing the area with turf.