As soon as possible. If your dog was old enough to be adopted, they’re old enough to get started with bathing, brushing, and nail trimming as needed. When puppies get used to being in water or having their paws handled at a young age, they find these activities less stressful as they get older. We always start slowly with puppies and give them lots of treats, so we can help them form a positive association with grooming from a young age.