Grass not growing back in unroofed zone?

[Anrui]

I made an unroofed pen (with wooden walls) for my tamed, non-trained animals like muffalo and alpaca and at one point when I just had 2 muffalo there was a period where my cooks weren't making kibble and they ran out of food and ate all of the grass in their area. It's been nearly a year now and no grass has grown back. Since that blunder, I've been sure to keep their kibble feed well stocked but no grass has grown back yet.

It might be because of the walls, I am not sure if the grass seeds can pass through walls or not (when there is soil and the zone is unroofed). I'm reporting this just in case it really is a bug though. Let me know otherwise though. Thanks.

[Chibiabos]

My guess would be its because of the walls.  I cringe hard when there's Toxic Fallout -- I'm pretty good at housing my colonists safely, but it kills every last animal and plant on the map.  The animals come back from the edge, but the grass and other plants (including trees) never fully repopulate the map, and mostly just at the extreme border of the map, so there's no grass or anysuch on most of the map.  I wish you could do some kind of native grass replanting that will spread seed in the surrounding un-zoned wild terrain.

[Anrui]

Maybe instead of adding new grass that might not have any uses beyond repopulating the map, what if hay could spread grass seeds? I feel like if some sort of way to plant grass was an option there would need to be more to it than simply repopulating the map. I was thinking there could be a way to turn it into fertilizer but that could get a little OP I feel.

[Tynan]

For now, it's by design, since grass on spreads by direct seed shots. It doesn't magically reappear map-wide. So, maybe something to redesign, but not a bug.