Dog spot is caused by dogs urinating on the lawn and is usually worse with bitches because of their concentration of spray. The evidence of this is round dead brown spots on the lawn, quite often surrounded by areas of lush green growth.

Dog urine has a high concentration of ammonium nitrate, which can kill the grass. This is aggravated when synthetic fertilisers with high levels of nitrogen are combined with the high levels of ammonium nitrates. The grass cannot cope with this abnormal level, tipping it over the edge and killing it.

Using natural fertilisers with a more balanced level of nitrogen will help this problem
enormously, although the best course is not to let your dog urinate on the lawn or if it does to spot water the area.