How often to feed cat grass depends on the cat's specific situation and needs. Generally, if the cat is shedding, it's recommended to feed it cat grass every two to three days to help remove excess hairballs and prevent hairball syndrome. If the cat isn't shedding, feeding it cat grass once a week is usually sufficient. However, during peak shedding seasons like summer, it may be necessary to feed it cat grass daily or more frequently. But please note that under no circumstances should cat grass be given more than three times a week to avoid irritating the cat's gastrointestinal tract.

At the same time, the amount of cat grass fed should also be controlled. The amount of cat grass given each time should not be too much, about 5 grams is sufficient. The specific amount of cat grass can be adjusted appropriately according to the cat's weight, age, and health condition.
Please note that some cats may not be interested in or tolerate cat grass. In this case, you can try mixing cat grass into their cat food or treats, or choose alternatives such as hairball remedy to help your cat remove hairballs.