Grass wont grow on res?

I bought some grass blocks from the Empire shop and duly stuck them down on my roof which I'm in the process of landscaping. I left them alone for a few days of RL time and have come back to find....... nothing's happened.

Anyone know why the grass isn't spreading across the other dirt blocks in my res?

They have light from the sun, they're on the roof.

Do you have fire spread flag turned off in your res? (if you do you would know that you set it)

Aaaah. Okay, so that affects grass growth? Right. Need to go and fireproof my building then as the last time I did /res default I turned around five minutes later to see three floors on fire. Massively on fire.

Well would you look at that.

Many thanks!

Yeah I need to fix that, its just the "spread" event in the server code also effects grass spreading but I think I can find a way around it

Not a problem. If you'd kept schtum on it I would've ended up spending a fortune in the Empire shop buying grass blocks instead!