Grass Treats for Cats

By Malcolm Weir, DVM, MSc, MPH; and Lynn Buzhardt, DVM

Why do cats eat grass?

There are a few theories about why cats eat grass. One theory relates to cats’ wild ancestry. Cats are meat-eaters, but their digestive systems are also adapted to process grass. In the wild, cats stalk and hunt for food. After consuming their prey (often small mammals or birds), they may nibble a little grass. Eating grass might make cats throw up the less digestible parts of their protein-rich meal (hair, bones, or feathers).

Another theory is that eating grass has health benefits. Grass is a source of needed trace minerals, micronutrients, and vitamins A, B, and D. Grass also contains folic acid, which impacts the production of hemoglobin, an important part of blood oxygenation.

Grass also contains chlorophyll, which may aid minor medical problems. Chlorophyll may have helped cats deal with infection and pain before the advent of modern-day antibiotics and anti-inflammatory drugs.

Today, most cats are cared for by people who feed them a nutritionally balanced diet, so they lack nothing. Even so, cats like to graze on grass, and grass benefits even well-fed cats. Grass provides roughage that aids digestion and elimination. Cats that eat grass routinely may have more regular gastrointestinal tracts, fewer hair balls, and less constipation. Plus, the chlorophyll in grass helps keep a cat’s breath fresh. Finally, cats just like chewing on grass, so it provides entertainment.

How much grass is appropriate?

Moderation is key. Cats don’t have the necessary digestive enzymes to process large quantities of grass and overeating can result in excess vomiting. Conversely, if the cat doesn’t throw up, the insoluble fiber in grass can potentially build up and cause an intestinal blockage. A good rule is that treats of any kind, including grass, should comprise no more than 10% of a cat’s total caloric intake.

What kind of grass is the best?

Cat grass usually refers to grass that produces cereal grains, such as oat, wheat, barley, alfalfa, and rye. You can start with one variety or plant a couple of different grasses, then assess your cat’s preference. You can also consider which variety grows best in your home. Outdoor cats may graze on a variety of grasses, while indoor cats depend on their owners for grassy snacks. It is important to note that grass and catnip are not the same thing. Catnip is a member of the mint family.

How do you grow cat grass?

Even if you aren’t a master gardener, you can probably grow enough grass to keep your cat happy. Here are a few tips to help you with your indoor garden.

Choose a shallow container with drainage openings. Heavier containers are better because they are less likely to tip over when your cat paws at the grass or tries to walk on the “indoor lawn." Purchase regular potting soil. Look for grass seeds online or at a local nursery or pet store.

Plant seeds in shallow soil. Fill the container ¾ full of potting soil. Sprinkle seeds evenly on the surface, then cover the seeds with ¼-inch of potting soil and water with a spray bottle. Cover the container loosely with plastic wrap and keep it at room temperature, out of direct sunlight, until the seeds sprout. Green sprouts should emerge within 3 to 7 days.

Water seeds consistently. Some people advise soaking grass seeds before planting, but many gardeners plant seeds directly from the packet. Regardless of your preference prior to planting, it is important to keep newly planted seeds constantly damp for several days.

Move into the sun. Once seeds spout, remove the plastic wrap and move the container to a location that receives direct sunlight. Water sparingly to keep the soil damp but not wet. Too much water may cause mold to grow and ruin your garden. Place your finger on the soil and re-water when it feels dry to the touch. The grass should be ready to eat within 10 to 14 days or when it reaches a height of about 4 inches (10 cm). The crop of grass should last up to three weeks.

Pull out old shoots and plant more. When the grass wilts or turns yellow, pull out the dying shoots. You may plant more seeds in the same container or plant a whole new batch. If your cat really enjoys the grass, you may plant several pots about a week apart and rotate them to provide a constant source of fresh grass.

If you’d like to streamline your efforts, you may purchase a complete grass growing kit with everything you need, including detailed instructions.

Are there any dangers for a cat eating grass?

There are a few warnings to consider when giving your cat grass.

First, not all green things are good for your cat. Some plants are poisonous, and cats may not distinguish between safe and dangerous plants. If your cat is used to eating grass, she may assume that she can snack on anything green, such as the toxic rhododendron on the windowsill or the poisonous tiger lily on the sun porch. Keep dangerous plants out of reach in case your cat decides to expand her palate from grass to harmful plants.

Another possible danger posed by cat grass is the presence of mold. Ingestion of mold will challenge the digestive tract and can be toxic. If your grass begins to look sickly, remove the planter and cultivate a new batch.

If your cat eats grass indoors, he may also try to nibble the lawn outside. Eating outdoor grass can be harmful if it has been treated with pesticides. In addition, intestinal parasite eggs often survive in soil for long periods of time. Fortunately, most cats just nibble the top of the grass, but if your cat grazes down to the roots and consumes a little dirt along with her greens, she can become infected with intestinal parasites.

Does my cat need grass?

Your cat does not need to eat grass. If you have questions about feeding your cat grass, talk to your veterinarian. With your cat’s overall medical status in mind, your veterinarian can give you sound advice on the advantages and disadvantages of adding grass to your cat’s diet.

© Copyright 2025 LifeLearn Inc. Used and/or modified with permission under license.

Related Articles