Choosing the right seed and tray
Cat grass is not one plant but a group of young cereal grasses — oats, wheat, and barley are the usual choices, with oat grass often the softest and sweetest for picky cats. Buy seed sold for sprouting or labelled for pets, and avoid lawn seed, which may be treated and is grown for toughness rather than nibbling. If your cat has ignored grass before, try oats first before deciding she is simply not a grazer.
The container matters more than it looks. A shallow, wide tray gives the roots an even mat and is harder for a cat to tip than a tall narrow pot, especially once she starts pulling at blades with her teeth. Choose something heavy or place the tray inside a heavier outer dish, and expect a determined cat to drag grass across the floor at least once while she learns it is a buffet, not a toy.
Sowing, watering, and getting the light right
Fill the tray with plain, untreated compost or potting mix, firm it gently, and scatter the seed thickly in a single layer — sparse sowing gives a thin, disappointing tray that is grazed out in a day. Press the seed into the surface, cover it with a thin dusting of compost, and water with a spray or a gentle pour until the mix is evenly damp but not swimming. Keep the tray somewhere warm, and cover it loosely for the first days to hold moisture while the seed swells and splits.
Once green shoots appear, move the tray into the brightest spot you have that is not scorching direct sun through glass. A windowsill suits most flats, and turning the tray a little each day stops the grass leaning into one pale direction. Water little and often from then on; the roots sit shallow, so the surface dries fast, but a tray left standing in water quickly smells sour and grows mould at the base, which means starting that tray again rather than offering it.
Offering it so grazing helps rather than makes a mess
Wait until the blades are a good hand's height and sturdy before the first offering, because tiny shoots pulled by an eager cat come up roots and all. Put the tray down for defined grazing sessions at first, perhaps after a meal, and lift it away afterwards; constant access to a young tray usually ends with the whole crop flattened, dug in, or used as an alternative litter surface by one inventive cat in every neighbourhood.
A little grass chewing is normal cat behaviour and many cats enjoy the taste, the fibre, and the occupation. Some cats bring a small amount back up along with swallowed hair, which is common, but repeated vomiting, grass gorging as if she cannot stop, or grazing alongside appetite loss is a reason to mention it to your vet rather than simply growing more. Keep the tray away from houseplants she should not chew, because a cat taught that indoor greenery is food may generalise the lesson.
The two-tray rotation that keeps supply steady
One tray runs out fast: blades yellow, growth slows, and the mat becomes tough within a couple of weeks of good grazing. Run two trays a week or so apart instead. While tray one is being grazed, tray two is sprouting on the windowsill, and when tray one looks tired you compost it, reseed it the same day, and promote tray two. Fresh seed each cycle gives a far better result than trying to coax a cut tray back to life.
In a shared home the rotation fails when everyone assumes someone else watered the seed, so put the small jobs in writing: who sprays the sprouting tray each morning, who resows on rotation day, and who checks for mould before offering. Recording those little recurring duties in KinsLe's Care Teams, where each finished watering or sowing is marked with a timestamp, keeps the grass cycle turning smoothly without a single soggy or forgotten tray.