How to Grow Cat Grass Indoors: A Simple Step-by-Step Guide

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Cat grass is one of the easiest and most rewarding things you can grow indoors. It sprouts in days, gives your cat a safe outlet for their grass-chewing instinct, and — bonus — can save your prized houseplants from curious teeth. Here’s exactly how to grow it, and the vet-backed reasons it’s good for your cat.

What is cat grass?

“Cat grass” isn’t one specific plant — it’s a mix of cereal grasses grown from seed, usually oat, wheat, barley, or rye. It’s completely different from lawn grass (which may carry pesticides) and from toxic ornamental “grasses.” Grown in a little tray on your windowsill, it’s fresh, clean, and safe.

Why do cats eat grass?

It’s normal feline behavior, and there are a few solid theories. According to VCA Animal Hospitals, grass provides roughage that aids digestion and elimination, and cats that eat grass routinely may have more regular digestion, fewer hairballs, and less constipation. Grass is also a source of trace minerals and folic acid, which supports healthy blood.

The Cornell Feline Health Center notes that if your cat craves vegetable matter, safe alternatives like oat grass, catnip, and catmint are a great way to satisfy the urge — instead of letting them munch a potentially toxic houseplant. Growing your own cat grass is the simplest way to offer exactly that.

Kijani Paws pick

Organic Cat Grass Growing Kit

The no-fuss way to start: seed, soil, and a tray in one box. Just add water and light. It’s the easiest project on this whole site — sprouts in a few days and gives your cat a safe green to graze.

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How to grow cat grass, step by step

1. Fill a shallow container (2–3 inches deep) with pre-moistened potting mix, leaving about half an inch at the top. A wide, low tray works best so your cat can reach the whole thing.
2. Sprinkle the seeds generously and evenly across the surface — you want a dense, lawn-like carpet.
3. Cover lightly with about a quarter inch of soil and mist the top until evenly damp.
4. Create a mini greenhouse. Loosely cover with a clear lid or plastic wrap and keep it in a warm spot out of direct sun until sprouts appear — usually 2–4 days.
5. Uncover and give it light. Once seedlings pop up, remove the cover and move the tray to a bright windowsill or under a grow light.
6. Serve at 3–4 inches. In about 7–10 days the grass reaches snacking height. Set it where your cat hangs out and let them graze.

Keeping it fresh

Mist or lightly water the grass daily to keep the soil moist but never soggy. A tray typically stays lush and appealing for 1–3 weeks. When it starts to yellow or flop, simply start a fresh tray — many owners stagger two trays a week apart so there’s always a green one ready. Growing multiple small trays also keeps your cat interested and spreads out the harvest.

Is cat grass safe? (yes)

Cat grass grown from oat, wheat, barley, or rye seed is non-toxic and safe for cats to eat in normal amounts. It’s actually one of the best tools for protecting your other plants: a cat with its own grass buffet is far less tempted to chew a toxic houseplant. Keep the tray pesticide-free (that’s the whole point of growing your own), and don’t let a cat gorge to the point of repeated vomiting — occasional grass-related hairball vomiting is normal, but constant vomiting is worth a vet call.

FAQ

How long does cat grass take to grow?
Seeds sprout in 2–4 days and reach snacking height (3–4 inches) in about 7–10 days.

Do I need special seeds?
Just cereal grass seed — oat, wheat, barley, or rye. A pre-made kit bundles everything, which is the easiest start.

Is cat grass the same as catnip?
No. Cat grass is a cereal grass for grazing; catnip (and catmint) is an herb that triggers a behavioral “high.” Both are cat-safe and can be grown indoors.

My cat vomits after eating grass — is that bad?
Occasional vomiting after grass is normal and may help clear hairballs. Frequent or forceful vomiting is not normal — check with your vet.

The bottom line

Growing cat grass indoors takes a tray, some seed, water, and about a week. It satisfies a natural instinct, supports digestion, and quietly protects your houseplants from curious teeth. It’s the single easiest, most cat-pleasing thing you can grow.

Round out your pet-safe home with our best cat grass kits review and a look at how to keep cats away from your other plants.

Sources

• VCA Animal Hospitals — Grass Treats for Cats
• ASPCA — Toxic and Non-Toxic Plants database
• Pet Poison Helpline — Top Plants Poisonous to Pets

Written by Mo Ruman, a self-taught plant parent who cross-checks every plant against the ASPCA database. Not a vet — when in doubt, call yours. More about Kijani Paws · Ask me about a plant. As an Amazon Associate, Kijani Paws earns from qualifying purchases; this never affects our safety information.