Question: Why does my dog keep eating grass?
Answer: Some dogs will just graze because they like the taste, but if your puppies are doing it continually and bringing it up after, you should check their diet and be sure you are feeding a nutritionally balanced dog food.
The other thing to watch out for ...
Keep an eye on them, dogs have a tendency to eat grass when something is upsetting their stomaches, as it will bind the item that bothers them, and help them to bring it up after.
Check your plants, this is a common cause.