Why do cats eat grass? Many cat owners wonder about this, and scientists still don’t have a definitive answer. One thing is clear: it’s natural behavior for both pet cats and wild cats, and growing your own cat grass is a safe, easy way to satisfy it.
Why Do Cats Eat Grass?
Read also: Plants that are poisonous to cats
Here are the main theories:
- Instinct. A study by researchers at the University of California, Davis, found that grass eating is very common in cats and that most cats eat grass without vomiting afterward or showing signs of illness. One theory is that it’s an inherited behavior from wild ancestors: eating plant material may have helped wild cats move intestinal parasites through the gut.
- Moving things along. Grass contains fiber that may help move food and hair through the digestive tract. It may have a mild laxative effect in some cats.
- Hairballs. Cats swallow a lot of hair while grooming. Some cats vomit after eating grass, which may help them bring up hairballs or other things that are bothering their stomach. That said, most cats that eat grass don’t vomit.
- Nutrients. Grass contains small amounts of folic acid (vitamin B9) and other nutrients. However, a cat eating a complete and balanced diet gets everything it needs from its food, so a lack of nutrients isn’t likely to be the main reason.
- Taste and texture. Some cats don’t really swallow much grass at all: they just chew the juicy green blades because they like the taste and texture.
What Grass Should You Grow for Your Cat?
Remember that cats sometimes chew on plants that are dangerous to them. So when choosing seeds to grow, pick safe grasses that cats love:
- wheat grass;
- barley grass;
- oat grass;
- rye grass.
If you’re not sure which one your cat will like, try a mix. Many pet stores sell “cat grass” seed mixes and kits. Catnip and cat thyme are other safe plants that many cats enjoy.
Despite its name, “cat grass” isn’t a specific plant. Make sure the kit you buy contains cereal grasses like wheat, oats or barley, and never confuse grasses with lilies or other toxic plants.
How to Grow Cat Grass
Don’t bring grass in from outside for your cat. Outdoor grass may be treated with fertilizers, weed killers or pesticides, contaminated by dog urine or car exhaust, or carry parasites. It’s much safer to grow cat grass at home, or to buy a ready-grown pot from a pet store or garden center. When you grow it yourself, you know it’s safe and healthy for your cat.
To grow cat grass at home, you’ll need:
- seeds (buy a packet from a pet store or garden center);
- a growing medium: organic potting soil without added fertilizers, or vermiculite (a light mineral sold in garden centers and in many cat grass kits), or even just damp paper towels or cheesecloth for a quick crop;
- a container: a shallow pot, a tray or a sturdy, heavy bowl that your cat can’t easily knock over, ideally with drainage holes;
- plastic wrap or a clear bag to create a mini greenhouse.
- Prepare the seeds. Rinse the seeds and soak them in cool water for a few hours or overnight.
- Plant. If you’re using soil, fill the container, leaving a little space at the top. Scatter the seeds evenly on the surface, then cover them with a thin layer of soil, about 1/4 inch (5 mm). If you’re using vermiculite, soak it along with the seeds, drain the water and spread the mixture in the container. If you’re using cheesecloth, place it on the bottom of the container, spread the seeds over it and cover them with another layer.
- Water. Water the soil gently, or mist the vermiculite or cheesecloth so it’s damp but not soggy.
- Cover. Cover the container with plastic wrap or a clear bag to create a greenhouse effect.
- Keep it warm. Place your mini garden in a warm, bright spot, but out of direct heat, such as a radiator or heater, which can dry it out. The seeds usually sprout in 2 to 3 days. Remove the cover once the shoots appear, after about 3 to 4 days.
- Serve. After about 7 to 10 days, when the grass is 3 to 4 inches (8–10 cm) tall, you can offer it to your cat.
Keep the grass in a bright spot and water it when the soil feels dry, without overwatering, which can cause mold. Trim off any yellow or brown blades. Cat grass usually lasts two to three weeks before it starts to wilt, so many owners plant a new batch every week or two to always have fresh grass on hand. Throw it out if it becomes moldy.
What If Your Cat Won’t Eat Grass, or Eats Too Much?
Not all cats are interested in plants, including cat grass. There’s no need to force your cat to eat grass or to mix chopped grass into its food: if your cat isn’t interested, that’s perfectly fine.
On the other hand, if your cat suddenly starts eating a lot of grass or plants, vomits frequently, has diarrhea, loses weight or seems unwell, talk to your vet. It could be a sign of a digestive problem, an upset stomach or another health issue. Read more about brushing your cat to help reduce hairballs, and our tips on caring for a kitten.
How Much Does Cat Grass Cost?
- Seed packets: about $3–8 / £2–5.
- Grow kits with seeds and growing medium: about $5–15 / £4–12.
- Ready-grown pots: about $5–12 / £3–8.
Buy seeds from reputable pet stores or garden centers, and avoid seeds of unknown origin, which may be poor quality or treated with chemicals that are harmful to cats.
