So i have 2 indoor cats. This model is meant to keep the grass seeds inside, so they can't pull it out when eating the grass.

I printed this in white ASA, it can also be printed in PETG. To prepare the grass, you should get the seeds (usually it comes with vermiculite or something similar), put some cotton balls inside the planter, spray it with water so it's damp. On top, put the mix of seeds and vermiculite, or just seeds. Spray with water, cover with the printed lid and then cover everything with damp paper towel for few days. Keep the towel damp. Soon, the grass will grow through holes.

EDIT: Reuploaded the lid file, because i messed up the files when uploading. Should be fine now. I deeply apologize to anyone that printed the file and it didn't fit.