In the garden should be fine, as long as you spread it around well. May be too concentrated and alkaline for pots.

Depends on the fuel you're using - if its wood, then you can sprinkle it about, if its from coals, you can't.

I'm possibly ignorant, because we hardly ever see coal here, but:

BARBEQUEING ON COAL!!?? AACCKK! PHHHPPTT! BLECH!!

I sort of agree, Tubrethil, but we do use coals a lot here and, much, much worse I think, barbecue lighter fuel, eugh, taints the food...

Too much like one of my neighbors. After a six-pack or two, he decides to have a barbeque, then nearly immolates himself with 2 l of charcoal, and 4 l of lighter fluid! KaWHUMPH!! YAHEEOW!!! At least he doesn't have to worry about people inviting themselves over. : D