The grasses safe for cats are the same ones sold as “cat grass” at pet stores: wheat grass, oat grass, barley grass, and rye grass. These are all young cereal grains harvested as tender shoots, and none are toxic to cats. You can buy them pre-grown or easily grow them yourself on a windowsill.
The Four Standard Cat Grasses
Cat grass is a general term for a mix of oat, rye, barley, and wheat grasses. They’re all nutritionally similar and safe, but each has slight differences worth knowing about.
Oat grass is often considered the best single choice. It acts as a digestive aid that helps calm the intestinal tract, is relatively high in protein and soluble fiber, and contains iron, manganese, zinc, and B vitamins. Its blades tend to be soft and appealing to most cats.
Wheat grass is the variety you’ll find most often in stores. It grows quickly and produces dense, bright green shoots. Nutritionally it’s comparable to oat grass, with a good fiber content that can help move hairballs through the digestive system rather than letting them sit in the stomach.
Barley grass and rye grass round out the typical cat grass mix. They’re slightly hardier plants and a bit coarser in texture, but equally safe. Many commercial cat grass kits blend all four seeds together so your cat gets variety in one pot.
Alfalfa: A Less Common Option
Alfalfa isn’t technically a grass (it’s a legume), but some veterinarians specifically recommend it for cats. It has shown potential benefits for preventing and treating kidney disease, which makes it an interesting option for older cats or breeds prone to renal problems. Alfalfa sprouts are easy to grow at home using the same methods as cat grass.
Why Cats Eat Grass in the First Place
Cats are obligate carnivores, so grass isn’t a nutritional requirement. A well-balanced cat food covers all their dietary needs. Still, many cats actively seek out grass, and there are a few plausible reasons why.
The most widely accepted explanation is fiber. Insoluble fiber from grass blades can act as a mild laxative, helping hairballs pass through the intestinal tract instead of being vomited up. In some cats, grass triggers vomiting instead, which can expel hairballs or other indigestible material from the stomach. Both outcomes are normal. Grass also provides environmental enrichment, giving indoor cats something to investigate, chew on, and interact with throughout the day.
How Much Grass Is Too Much
You can leave cat grass freely available without worry. Most cats self-regulate and nibble small amounts. However, if your cat eats grass voraciously, almost compulsively, that’s worth paying attention to. It could signal that their regular diet isn’t meeting all their nutritional needs, or it may indicate a gastrointestinal issue. Occasional vomiting after eating grass is normal. Frequent vomiting, or vomiting that continues even without grass, is not.
Growing Cat Grass at Home
Cat grass is one of the easiest things you can grow indoors. Scatter seeds over a pot of organic potting soil, cover them lightly, and water well. Keep the pot in a dark spot for the first two to three days while the seeds germinate, then move it to a sunny windowsill. By day four, you’ll see pale green shoots turning deep green as they soak up light.
The grass reaches snacking height within about a week. Indoors, a pot typically lasts one to three weeks depending on how much light it gets and how enthusiastically your cat grazes. Pots that get strong natural light or live on a screened patio can last up to three weeks. Weak indoor light shortens the lifespan to closer to one week. A good strategy is planting a new pot every two weeks so you always have a fresh supply ready.
If you don’t have a sunny window, fluorescent plant lights work well. Position them three to four inches above the pot, run them for 16 hours a day, and raise them as the grass grows. Regular incandescent bulbs generate too much heat and won’t work.
Grasses and Plants to Avoid
The biggest risk isn’t the grass itself but what’s on it. Outdoor lawn grass is often treated with herbicides containing chemicals like glyphosate, 2,4-D, dicamba, and triclopyr. Cats that eat treated grass can develop vomiting, diarrhea, weakness, excessive drooling, and weight loss. Symptoms can appear within 30 minutes to two hours. Even if you don’t treat your own lawn, neighbors’ applications can drift. If you let your cat outdoors, don’t assume the grass is clean unless you’re certain no chemicals have been applied. At minimum, wait until any application has dried completely before allowing access.
Outdoor grass also carries the risk of intestinal parasites from other animals’ feces, which is another reason indoor-grown cat grass is the safer choice.
Several plants that look grass-like are genuinely dangerous to cats. Grass palm (sometimes called giant dracaena or palm lily) has long, blade-shaped leaves that resemble grass but is toxic. Lemongrass, listed by the ASPCA as toxic to cats, is a common garden herb that cats might encounter outdoors. While lemongrass essential oil has been studied as a feed additive and found safe for cats only at very low concentrations (33 mg per kilogram of feed), the plant itself can cause stomach upset, and concentrated lemongrass oil is an irritant to skin, eyes, and the respiratory system.
Lilies deserve special mention because some varieties grow in garden beds near grassy areas. All true lilies, including Easter lilies, Asiatic lilies, tiger lilies, and lily of the valley, are extremely toxic to cats. Even small exposures can cause kidney failure. Sago palms (cycads) are another outdoor plant that’s severely toxic. If your cat has access to a garden, check for these plants and remove them or fence them off.
Indoor Cat Grass vs. Outdoor Grass
Growing cat grass indoors gives you complete control. You know exactly what’s in the soil, there are no pesticide residues, and there’s no parasite risk. A simple pot of oat or wheat grass on the kitchen counter is the safest, easiest way to give your cat access to greens. The seeds are inexpensive (a few dollars for months’ worth), and the whole process from planting to snacking takes less than a week.