No recent updates because for the last two days I've literally been watching grass grow.
Also, I'm pretty sure everyone's off the internet by now because of HSC.
I'll try and keep this short:
Grass grows on dirt when grass is next to it.
Grass is not transportable.
So basically, if you want grass in the sky, you're going to have to connect it to the ground somehow.
Grass also requires sunlight to grow. Each 24 hour cycle in game is about 20 minutes.
Grass grows upwards, diagonally at 2 blocks a day, if you're LUCKY.
My fortress is about 30 blocks up from the ground.
Every 1 hour, I get 6 blocks of grass maximum. (Occasionally, it just doesn't grow at all).
In short, I had to keep the game open for 5-6 hours for grass to climb a staircase.
Additionally, I'm waiting for the grass to cover the lawn. (Isn't as slow, but it'll surely take about an hour.)